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VOL. XXXV JUNE, 1934 No. 414 JOURNAL OF THE NEW YORK BOTANICAL GARDEN HARDINESS IN PLANTS HENRY TEUSCHER NEW ROSES FROM PERSIA REPORT OF THE SOUTHERN APPALACHIAN EXPEDITION— II EDWARD J. ALEXANDER HYBRIDS BETWEEN THE NECKLACE COTTONWOOD AND THE LARGE- LEAVED ASPEN A. B. STOUT TWO IMPORTANT NEW BOOKS FOR GARDENERS CAROL H. WOODWARD PUBLISHED FOR THE GARDEN AT LIME AND GREEN STREETS, LANCASTER, PA. THE SCIENCE PRESS PRINTING COMPANY Entered at the post- office in Lancaster, Pa., as second- class matter. Animal subscription $ 1,00 Single copies 10 cents Free to members of the Garden THE NEW YORK BOTANICAL GARDEN BOARD O F MANAGERS I. ELECTIVE MANAGERS Until 1935: L. H. BAILEY, THOMAS J. DOLEN, MARSHALL FIELD, MRS. ELON HUNTINGTON HOOKER, KENNETH K. MACKENZIE, JOHN L. MERRILL ( Vice- president and Treasurer), and H. HOBART PORTER. Until 1936: ARTHUR M. ANDERSON, N. L. BRITTON, HENRY W. DE FOREST ( President), CLARENCE LEWIS, E. D. MERRILL ( Director and Secretary), HENRY DE LA MONTAGNE, JR. ( Assistant Treasurer & Business Manager), and LEWIS RUTHERFURD MORRIS. Until 1937: HENRY DE FOREST BALDWIN ( Vice- president), GEORGE S. BREWSTER, CHILDS FRICK, ADOLPH LEWISOHN, HENRY LOCKHART, JR., D. T. MACDOUGAL, and JOSEPH R. SWAN. I I . EX- OFFICIO MANAGERS FIORELLO H. LAGUARDIA, Mayor of the City of New York. ROBERT MOSES, Park Commissioner. GEORGE J. RYAN, President of the Board of Education. III. APPOINTIVE MANAGERS A. F. BLAKESLEE, appointed by the Torrey Botanical Club. R A. HARPER, SAM F. TRELEASE, EDMUND W. SINNOTT, and MARSTON T. BOGERT, appointed by Columbia University. DIRECTOR EMERITUS N. L. BRITTON, P H . D., SC. D., LL. D. GARDEN STAFF E. D. MERRILL, SC. D Director MARSHALL A. HOWE, P H . D., SC. D Assistant Director H. A. GLEASON, P H . D Head Curator JOHN K. SMALL, PH. D., SC. D Chief Research Associate and Curator A. B. STOUT, P H . D Director of the Laboratories FRED J. SEAVER, P H . D., SC. D Curator BERNARD O. DODGE, P H . D Plant Pathologist FORMAN T. MCLEAN, M. F., P H . D Supervisor of Public Education JOHN HENDLEY BARNHART, A. M., M. D... Bibliographer and Admin. Assistant PERCY WILSON Associate Curator ALBERT C. SMITH, P H . D Associate Curator SARAH H. HARLOW, A. M Librarian H. H. RUSBY, M. D Honorary Curator of the Economic Collections FLEDA GRIFFITH Artist and Photographer ROBERT S. WILLIAMS Research Associate in Bryology E. J. ALEXANDER Assistant Curator and Curator of the Local Herbarium HAROLD N. MOLDENKE, P H . D Assistant Curator CLYDE CHANDLER, A. M Technical Assistant ROSALIE WEIKERT Technical Assistant CAROL H. WOODWARD, A. B Editorial Assistant THOMAS H. EVERETT, N. D. HORT. Horticulturist HENRY TEUSCHER, HORT. M Dendrologist G. L. WITTROCK, A. M Docent ROBERT HAGELSTEIN Honorary Curator of Myxomycetes ETHEL ANSON S. PECKHAM . . Honorary Curator, Ins and Narcissus Collections WALTER S. GROESBECK Clerk and Accountant ARTHUR J. CORBETT Superintendent of Buildings and Grounds JOURNAL OF The New York Botanical Garden VOL. XXXV JUNE, 1934 No. 414 HARDINESS IN PLANTS1 As long as I have been engaged in horticulture, I have been interested in the problems pertaining to hardiness in plants. Anxious from the first to familiarize myself with the peculiarities of the plant material with which I was working, I began taking local notes on the manner in which various plants survived the winter. That seemed simple enough. But the second year, when I set out to verify and complete my notes, I found that plants which I had marked down as hardy during the previous severe winter appeared to be tender, though the season had been much milder. I concluded that my observations had been at fault, and continued taking notes, extending my observations from the Imperial Parks at Potsdam to the Botanical Garden at Dahlem- Berlin. But after three or four winters my notes had become so complicated and contradictory that I commenced to suspect that temperature was not alone the deciding factor in the hardiness of plants. My view was confirmed by many experienced gardeners whom I consulted. It became apparent that the condition in which a plant entered the winter— which in turn depended upon the preceding growing season, as well as on local conditions— was of at least as much, if not of greater, importance. In the twenty years since then, the subject has never ceased to absorb my attention. Out of the innumerable strange instances of hardiness which I observed ( some of which I shall cite later on), I have learned, in particular, two things: 1 A lecture given before the Conference of the Scientific Staff and Registered Students of The New York Botanical Garden, on April 12, 1934. 121 First: That it is possible to grow a great many more plants out of doors than is generally believed, provided that we do not give up in despair after the first failure but rather follow the plant closely through its life cycle for several years and adjust gradually the conditions under which it grows until they are most favorable to bring about hardiness. The first trial has to be based on a guess, and it is a method of hit or miss, but this is still the best we can do. After a few successes we will find that it will become easier and ever easier to guess right from the start. Second: I have learned that it is frequently quite impossible to say of a plant outright, " It is hardy." I have learned to say instead, " It can be grown successfully outdoors in this vicinity," which implies that it is hardy provided that conditions and treatment are right. In outlining what constitutes and what influences hardiness I shall commence with the results of the investigations of the physiologists, then quote the observations of the practical horticulturist and gardener, and conclude with a preliminary report on the injuries which have resulted from this past severe winter. The physiologists, in general, agree that winter hardiness is a very indefinite and complex matter, depending on numerous widely different factors which often exclude one another, and that it is not necessarily identical with frost resistance. The resistance to severe dehydration, the ability to remain dormant through prolonged warm spells in the winter, and the capacity to stop and start growth at the most opportune times in autumn and spring, which means to be in tune with the changing seasons, are at least as important as the ability to withstand low temperatures. What actually is the life- sustaining factor at very low temperatures and what is the quality that renders one plant more resistant than another are still very much of a mystery, even to physiologists. The theory advanced by the Russian investigator, Govorov, that hardy plants fall into a state of anabiosis, during which respiration is almost suspended, certainly is interesting. He contends that in this state of anabiosis the hardy plant does not suffer from the deficiency of oxygen in the soil which, according to his opinion, is the main cause of death for non- hardy plants in the winter. Similar conditions of suspended life occur also in animals and even in human beings, as we all know, but in what this condition actually 123 consists, and what brings it about, we cannot expect to be able to explain until we have solved the eternal mysteries of life and death. What we do know, thanks to the research work of the plant physiologists of the world, is what goes on in the plant cell when it freezes and. when it dies from freezing; to a certain extent, also, what goes on in a cell which freezes but survives. From these researches it appears that when plant tissue is subjected to a sufficiently low temperature, ice is formed, in particular in the intercellular spaces toward which, with further lowering of the temperature, more and more water is drawn, first from the cell sap and finally also from the plasma. The physiologists are divided as to what causes the death of the plasma, if the temperature sinks too low. Some of them insist that death results from the chemical influence of the increased concentration of salts and acids on the colloids of the plasma, while others maintain that the plasma is injured mechanically by the compression of the cells caused by the ice crystals which accumulate in the intercellular spaces. I am not a judge, since I am not a plant physiologist and have never investigated these conditions, but it seems to me quite possible that both parties are right, and that either type of injury, perhaps even both simultaneously, may result, depending upon the kind of plant and the condition of the plant which is used for the experiment. In either case it seems to be important for the plant cell, in order to increase its hardiness, to decrease its content of free water which may be frozen, and this is, quite apparently, what actually happens. A method to use the condensation of the cell sap or the decreased free water content of the hardened cell, respectively, in order to measure the degree of hardiness of a plant, was first suggested by Newton, who experimented with different varieties of winter wheat. Pressing out the sap of uninjured leaves under pressure of 400 atmospheres, he found that hardened leaves gave up only an insignificant amount of sap, while tender leaves gave up their sap easily. In the protoplasm the water is bound by hydrophilic colloids which are formed during the process of hardening and which, to a certain extent, seem to prevent fatal dehydration. In the cell sap, water may be bound, for instance, by an increased sugar content. A concentrated sugar solution gives water off only slowly, 124 and the slower, the more concentrated it becomes. It seems, however, that the importance of the protective role of the sugars has been considerably overstressed. In the dormant, or, as the gardener says, ripened twigs of trees in the fall, there is noticeable a very marked condensation of the cell sap and a decrease in free water content, but there is no sugar. The cells of these dormant twigs are filled with starch. Sugar is not formed in these cells until after they have been subjected to low temperatures, and the sugar content gradually increases during the winter. In this connection I wish to mention the extremely interesting observations of Coville, who experimented at first with blueberries, but later also with many other plants, and who suggests quite a different role for the sugars in the cells of wintering plants ( as reported in the Journal of Agricultural Research, Oct., 1920). For purposes of cross- fertilization Coville brought some blueberry plants into a greenhouse with favorable growing temperature at the end of the summer. These plants refused to continue their growth, however. They gradually dropped their leaves and went into a state of complete dormancy, remaining in this condition in spite of a greenhouse temperature which in spring and summer would have kept the plants in luxuriant growth. When finally towards the end of winter other plants were brought in from the field, these latter at once burst into leaf and flower, while the indoor plants remained dormant as before. At first it was supposed that the plants needed to be frozen to start them into growth, but a single freezing proved ineffective. Then it was found that the dormant plants would start into growth without any freezing whatever. It was necessary only that they be subjected to a period of prolonged chilling, usually two or three months, at a temperature a few degrees above freezing. Plants kept continuously warm, without chilling, in some instances remained dormant for a whole year. In the course of his observations Coville reached the conclusion that the transformation of the stored starch into sugar which occurred in the dormant twigs during the period of chilling was the vital factor, and suggested that the development of high osmotic pressure caused by the concentrated sugar solutions in the cells might be the mechanism which started the plants into growth. In explanation of the formation of sugar during the process of 125 chilling, he advanced the theory that the starch grains stored in the cells of the plant are at first separated by the living cell membranes from the enzyme that would transform the starch into sugar, but when the plant is chilled the vital activity of the cell membrane is weakened, so that the enzyme leaks through it, comes in contact with the starch, and turns it into sugar. In view of these interesting suggestions it would be of vital importance for truly hardy plants to be able to remain dormant during prolonged spells of warm weather in February, after several months of chilling, and in spite of the rich sugar content of their cells. An explanation for this ability of many plants has not been advanced so far. The most interesting paper on the problem of hardiness in plants which I have come across, and to which Dr. Stout directed my attention, is one by the Russian, N. A. Maximow, entitled, " Internal Factors of Frost and Drought Resistance in Plants," published in 1929 in the Journal " Protoplasma." Maximow seems to have been the first to recognize the analogy between frost and drought resistance, and he gives an excellent review of the present state of both questions. From his own investigations, as well as by an extensive literature which he cites, he points out that in both cases the resistance lies in the capacity of the protoplasm to withstand the dehydrating influence of a direct or indirect deprivation of water, but warns at the end that this analogy must not be understood as identity. As we all know, plants resistant to drought are not always also frost resistant, and the capacity to resist low temperatures is not always accompanied by the capacity to endure severe desiccation. The controversy concerning the difference to a frozen plant, as to whether it is thawed out quickly or slowly, is perhaps not yet altogether settled. Molisch, who has experimented with a great many different plants, reached the conclusion that a plant either is killed in the freezing or remains uninjured also when thawed out quickly. This is in contradiction with the claim of all experienced gardeners. However, one has to consider that Molisch carried out his experiments in the laboratory while the gardener is dealing with plants in the open, where the drying effect of wind and sun is frequently the actual cause of injury during the process of thawing. The shading or sprinkling with water of frozen plants 126 in the early morning, which the gardener claims he does in order to slow down the thawing- out process, really serves mainly to prevent undue evaporation. Some exceptional cases where quick thawing actually proved injurious while slow thawing saved the tissue ( as, for instance, in the case of the leaves of Agave americana and flower buds of apple, which Molisch mentions) have not been explained as yet. The so- called " burning" of evergreen leaves and " sunscald" on tree trunks or twigs is also in reality a drying out. The tissues struck by the sun are unevenly warmed up, and the water which has been drawn out of the cells by the formation of ice is more quickly evaporated than it can be replaced, since the water- carrying vessels lower down in the tissue remain cold much longer and respond only sluggishly to the sudden demand. What causes and influences dormancy, or, as the gardener says, " ripening" of the wood, is not by any means perfectly clear. To a considerable extent it consists, undoubtedly, in an acquired habit and forms a part of the normal life cycle of a plant, most conspicuous in the plants of northern latitudes. The physiologist, as I said, admits that hardiness in plants is a very complex problem. The gardener does not always realize that, and the layman still more is frequently confused by the injury or the death of a plant which occurs— or seemingly occurs— in the winter, but which has nothing to do with hardiness. I have in mind, in particular, conifers and other evergreens which have suffered from severe drought during the summer. They are frequently already in a hopeless condition in the fall, though they do not show it, or their balls may have become so dry that no autumn rain can wet them and the further dehydration caused by the frost may kill them. That is why it is justly recommended to water conifers in the fall, or at least to make sure that they do not go into the winter with a dry root system. Other normally hardy plants may enter the winter in a weakened condition from having been planted in unsuitable soil; sun- loving plants from having been planted in the shade, or shade- loving plants in the sun. High alpine plants, or plants from the far North which in their native habitat are able to endure much lower temperatures than we ever get, may succumb to a mild winter with us after they have been weakened by our very long growing season or by other climatic 127 factors which are beyond our control. Such plants usually are adapted to a long winter during which they are covered with snow, which holds an even temperature, then a sudden transition from winter to spring and a rather short summer during which they have to finish their growth. They are therefore inclined to start growth in the spring as soon as the first warm days have thawed out the ground, which frequently proves their undoing in cultivation in the lowland. The experienced gardener knows that the way he will bring his plants through the winter depends very much on how he has treated them during the growing season and that, in particular, the following mistakes in treatment, or faulty conditions, or other factors frequently result in winter injury of some sort or other, or may cause tenderness in normally hardy plants: i— Late cultivation of the ground, which induces late growth and may result in the production of tender, unripened wood. 2— Late fertilising or over- fertilizing, especially with nitrogen fertilizers, which also may cause late, tender growth. 3— Superabundance of moisture, especially in rich soil with poor drainage, which causes a lush watery growth, suffering easily from freezing. This condition seems to favor, in particular, injury to the flower buds. 4— Permitting the plants to suffer from drought in the summer, which may cause a check in growth and may induce the plant to start growing again in late fall. 5— Mulching with moisture- holding or air- excluding litter, which may easily lead to rotting of the crowns of perennials. 6— Permitting a smothering overgrowth of aggressive neighbors and removing this overgrowth during the autumn cleaning. 7— Wrong pruning, especially sharp summer pruning of vigorous growing plants, which results in late growth and unripened wood ( climbing roses). 8— Propagation by cuttings, which, at least with certain plants, may result in the absence of a taproot ( this has been observed in particular with Phlomis fruticosa). The claim of many nurserymen that certain evergreens are hardier when raised from cuttings than from seeds, is not supported by facts. Seeds obtained from commercial seed-houses frequently come from southern strains which are tender, while cuttings are taken from plants which survived in the vicinity where the nurseryman is located, therefore they represent a hardier strain. This is especially true of Thuja plicata and Chamaecyparis Lawsoniana. 128 9— Production of a heavy crop of fruits, especially with grapes and certain fruit trees. The plant apparently extends its energies to the maturation of the fruits at the expense of wood and bud maturity, with the consequence that many of the unripened twigs and buds suffer frost injury during the winter. A light crop or crop failure frequently results in the following year. 10— Individual inclination of the plant, which closely resembles what is termed " emotional makeup" in man. Many plants vary considerably in hardiness if raised from seeds, as I had occasion to observe in particular in a set of several hundred seedlings of Cornus Kousa at the Boyce- Thompson Arboretum. Similar variations I observed this spring on larger sets of seedling plants of Albizcia Julibrissin, Castanea crenata, Diospyros Lotus, Prunus cyclaminea, Pterocarya stenoptera, Rosa omeiensis pteracantlw, Stranvaesia Davidiana, and Cytisus scoparius. Of all of these, some plants were killed to the ground while others remained entirely, or almost, uninjured, yet they were growing side by side under absolutely identical conditions. 11— Exposure. Many shrubs which during the summer are benefitted by a southern exposure, suffer during the winter more or less severely on their southern side if not shaded. Others ( also young trees) suffer severe injury in southern exposure while they may pass through the winter with no, or with only slight, injury in western or even northern exposure, provided they are protected against north winds. 12— Wrong planting, too deep as well as too high. 13— Late fall planting. Perennials, especially fleshy- rooted kinds, should not be planted late. Well- established shrubs or trees withstand sudden cold spells much better than those which have been planted within the last year or two, since their far- spreading root system is better in balance with their yearly growth. 14— Spring planting of pot- bound plants, which therefrom get a late start and may not be able to send their roots down deep enough to withstand the winter. 15— Neglecting to lift, divide, and replant certain perennials at reasonable periods causes aging and weakening of the plant. Old plants which are past the prime of their life and are on the down grade are more easily injured in the winter than are younger plants. In certain woody plants, especially, the very young plant also is tender to a certain age. In some instances there appears to be even a difference in the re- 129 sistance of the flower buds between young shrubs and older specimens. 16— Planting of trees which had dried out in shipment, especially in the fall. Such trees may frequently be saved by a covering of trunk and branches with paraffin wax. 17— Planting in so- called frost holes. The most excellent and concise explanation of the condition termed " frost- hole" which I have found, is given in a leaflet of the Weather Bureau of the United States Department of Agriculture, entitled, " Frost, when to expect it and how to prevent injury therefrom," written by W. H. Hammon, Professor of Meteorology. It may suffice to quote here from this text, which says that: In clear, calm nights the air arranges itself in layers, according to its density. The heavier cold air rests on the ground and in the valleys flows down the slopes, accumu- - lating on the lowest point when it can drain away no further. Places where cold air may accumulate in this manner must naturally be avoided, since especially during the vital weeks from early April to the later part of May, the temperature may drop considerably lower in such a frost- hole than on the surrounding slopes. When, after a late spring frost, only the lower branches or buds are found injured on a shrub or young tree, while the upper parts remain intact, there is suspicion of conditions resembling'a frost- hole, or at least insufficient air drainage on that particular place. When, on the contrary, for instance on a Forsythia bush, only the lowermost branches flower, the chances are that superabundance of moisture, viz., poor drainage, lowered the frost resistance of the buds. The lower branches were probably protected by snow or through shading from the upper branches. To INCREASE HARDINESS Conditions which assist in bringing about or in increasing the hardiness of plants are in particular, of course, the opposite of the above. The importance of drainage, which causes a stockier, hardier growth, I shall have occasion to point out later by examples. A cover crop of rye, wheat, oats, barley, or buckwheat sown in the summer similarly induces earlier ripening and consequent hardier growth, by taking care of surplus moisture as well as of surplus fertilizer. Such cover crops are employed in particular in peach orchards. 130 Winter protection consists in most cases in a protection against winter sun, drying winds, and the violent fluctuations of temperature which this winter sun causes, rather than in a protection against cold. Wrapping up may easily be overdone and will then cause more harm than benefit. Shading with burlap, as is done for instance with boxwood, or covering with pine branches, is usually much more effective. The wrapping- up with oil- paper, as has been recommended recently for roses in popular gardening magazines, is a dangerous practice, since the oil- paper acts as a sun trap and the fluctuations of temperatures between day and night are much more extreme under the paper than outside. Mulching, that is, a covering of the ground around the plant with leaf mould or old, well- rotted manure, can be recommended particularly for all recently planted or young plants and for all types of evergreens. Recent investigations have proved that the roots of most conifers especially remain active and continue to grow all through the winter. Since they are frequently rather shallow-rooting, the benefit derived from a mulch, which prevents violent fluctuations of the temperature of the soil, becomes easily understandable. REPORT I am now coming to the report on damages which have resulted from this last severe winter, and you are undoubtedly prepared to hear a long and sad list of losses. However, I can give you the cheerful news that the damage is by no means as serious as one might have expected. Most of the plants which I shall enumerate as having been killed altogether will hardly be known to you as outdoor plants— with the exception, of course, of the hybrid tea roses which were killed in many places, especially in light soil and where they had not been protected in the usual manner by heaping soil around the base of the bushes. The great majority of those plants had simply been under test, and, though many of them had done extremely well during the last two or three winters, I was well aware that their hardiness was doubtful and that the first really severe winter might cause their loss. When assembling plants for a botanical collection one has to test every plant that seems to have the slightest chance to succeed, since it is impossible to know of such a plant how hardy or how i3i tender it may prove to be until it has been tried. Nor, as I said before, does one trial and failure ever tell a fair story. In the above outline I explained how many factors there are which influence hardiness in plants. Not until all means have been exhausted to bring about the most favorable conditions for a plant, can it, in fairness, be called tender. Furthermore, most of the plants which I have to list today as dead, or severely injured, were plants, three to four years old, which were still in very vigorous growth. I said before that such young plants are almost always more tender than older, well- established plants. Most of these plants, also, were growing in nursery rows where cultivation had been kept up all through the summer to control weeds. This also tends to produce lush, tender growth. HENRY TEUSCHER. ( The death notices of the winter of 1933— 34 w^ oe given in subsequent issues of the JOURNAL.) NEW ROSES FROM PERSIA Several plants of a native rose from Persia which is believed to be nowhere in cultivation in the United States have been received by The New York Botanical Garden and now are growing where their flowering can be watched, in order to check the identification. They were secured by Mrs. William H. Moore, of 4 East Fifty-fourth Street, New York, a member of the Corporation of the Garden, while on a trip in the Near East during the spring. A release from the Federal Horticultural Board, when Mrs. Moore returned to New York in May, made it possible for the Garden to receive the plants for cultivation. 132 REPORT OF THE SOUTHERN APPALACHIAN EXPEDITION— II ( Continued from the May issue) Turning our attention west, we went out to Newport, Tennessee, and then down to Sevierville, from there entering the Great Smoky Mountains. There we collected seed of Cebatha Carolina, the red moonseed, a vine bearing dense clusters of red berries; Aralia spinosa, Cimicifuga americana, and Senecio Rugelia, and plants of Stcllaria pubera, the largest- flowered of the chickweeds, not at all weedy and very attractive for a shaded spot in the rock- garden. Cimicifuga americana is a much more handsome plant than the common C. racemosa, having spikes of much larger flowers, not so stiffly erect, and much lower in height, averaging 2— 3 feet. Senecio Rugelia is an extremely rare plant, known from only four or five stations high up in the Great Smokies. It is very unlike a Senecio, having large leaves somewhat similar to Aster macrophyllus and flower stalks with only 1- 5 large drooping heads of smoky- cream-colored flowers. It is not of great beauty, but is interesting for those who desire great rarities or unusual members of a genus usually markedly different. It grows in deep, mossy humus under the light shade at the edge of hemlock and spruce forests. Coming back into North Carolina and entering the Nantahala Gorge, we collected plants of Cymophyllus Fraseri, a sedge with Billbergia- like leaves and long- peduncled heads of feathery cream-colored flowers. Here also we found one plant of an albino of Lobelia siphilitica. Then passing across the south end of the Great Smokies back into Tennessee, we collected seed of Coreopsis major Oemleri; also Uniola latifolia, a grass with drooping slender- branched sprays, the branches terminating in flattened, oval heads which become reddish-tinged in fall; Helenium tenuifolium, an annual species with very slender leaves ; and plants of Silene virginica. Going to Knoxville, we turned west, collecting, on the limestone bluffs of the Clinch River, seeds of Manfreda virginica, a relative of the agaves. Helenium poly phyllum, a perennial species about one foot tall with numerous brown- centered heads, was collected near Rockwood. In a river swamp several miles from Chattanooga, 133 we collected seeds of Batodendron arboreum, the tree- blueberry, with numbers of drooping white flowers; Steironema tonsum, a relative of the Lysimachias; Elephantopus tomentosus, a composite with large basal leaves and heads of lavender flowers; Callicarpa americana, much more handsome than the usual cultivated species but not quite hardy in the north; Scutellaria ovalifolia, and Rham��nus caroliniana. W^ SMSMMFMI SHMPJHE K^ t- j^ HKBg., '"-^ t l& OTtuHn iiSaloiii^ l Hffm> wn^ nn^ Bi^ i^ El:! ilBOffiHi aaJSyllHPi FIGURE 5. A portion of the colony of Pamassia asarifolia in Neel's Gap, Ga., showing a typical healthy growth of this plant. Turning west again, we went out to Tullahoma and back to Chattanooga, collecting along the way seeds of Cassia marilandica, a perennial growing 2- 3 feet tall, with terminal sprays of yellow flowers; Verbena angustifolia, with upright spikes of small, lavender flowers; Liatris squarrosa and Liatris microcephala; Eupatorium incarnation, a sprawling plant with rosy- lavender flowers; Chry-sopsts Nuttallii; Bradburya virginica, a sprawling vine with lavender- purple, pea- like flowers 1- 1^ 2 inches across; and a pink- flowered, narrow- leaved Rhexia. 134 Back at Chattanooga, we ascended Lookout Mountain and there collected seed of Silene rotundifolia and a species of Penstemon. This Silene has round- ovate leaves and bright red flowers. It usually grows under shelving rocks, where it reaches a height of 10- 12 inches. When in the open it is much lower. Going back into North Carolina at Murphy, we collected along the way seed of Leonotis nepetaefolia, an introduced rather weedy plant from South America ; Vernonia altissima, and Liatris spicata. Near the Tennessee- North Carolina line, we collected plants of an albino of Aster sur-culosus. Returning to Asheville, we took a run out to Chimney Rock, obtaining along the Broad River seeds of Helianthus tomentosus, a handsome species with large, lemon- yellow heads; and collecting on Chimney Rock Mountain seeds of Talinum teretifolium, a fine rock plant with slender, fleshy leaves and rosy- purple flowers; Opidaster australis, Rhododendron minus, Coreopsis pubescens, a Penstemon, Rudbeckia triloba, Lonicera flava, Trautvesseria caro-linensis, two species of Philadelphus, and three species of Heuchera. It might here be stated that the eastern Heucheras cannot compare with H. sanguinca in showiness of flower. Their charm lies in the foliage and in the rather delicate small flowers, usually in graceful panicles. Back at Asheville, Mr. Everett left the party and returned to New York by train. We then went down into South Carolina, collecting a few plants of Senecio Millefolium at Caesar's Head, and seed of Coreopsis major at Westminster. Then passing over into Georgia, we zigzagged through the mountains to Blairsville, collecting en route seeds of Rhynchosia erecta, a plant about one foot tall with close clusters of pea- like, yellow flowers in the leaf- axils; Galactia volubilis, a sprawling or low-climbing relative of the beans, with short spikes of purplish- pink flowers; Isopappus divaricatus, an annual composite with a much-branched spray of small yellow heads, which should prove useful for bouquet arrangement; Passiflora incarnata, the native passionflower; a dwarf Ilex, covered with large red berries, though scarcely a foot tall; and Morongia angustata, the sensitive- brier, a vine which runs on the ground, bearing mimosa- like heads of pink flowers. 135 In Neel Gap, south of Blairsville, we came across a large colony of Pamassia asarifolia, by far the finest we had yet seen. The dripping ledges in a small stream and around it were covered with thousands of plants, many of which were in full flower. Continuing down to Atlanta, we climbed Stone Mountain and collected seeds of Gymnolomia Porteri, a sunflower- like annual composite, rarely exceeding a foot in height; Coreopsis saxicola, and Amorpha virgata; this being the type locality for all three of FIGURE 6. The range of mountains in North Carolina containing Table Rock, the sharp pinnacle in the left distance. Here one views the summit cap on edge from the north. The peak in the right distance is Hawksbill, ioo feet higher than Table Rock. these plants. We found also an Aster which appears to represent an entirely new group in the genus. Going from Atlanta to Rome, we collected seed of Brauneria pallida and a Penstemon. At Rome we collected seed of two species of Philadelphus, one Amorpha, and Clitoria mariana, a semi-vine with pea- like, lavender flowers 1— 1^ 2 inches long. Then turning west to Gadsden, Alabama, we collected en route seed of Coreopsis tripteris, a very tall- growing species with brown- 136 centered heads; MarshalUa obovata, an Allium, Helianthus mollis, Rudbeckia fulgida, with intense orange- yellow rays; Berchemia scandens, a woody vine related to Rhamnus, with glossy leaves and black fruits; Amorpha tenncsscensis, and Vernonia fiaccidifolia. The Marshallias are a group of southeastern composites resembling the Centaureas in the appearance of the flower heads, which are very pale lavender or pinkish, but the leaves are mostly basal, and the plants average about a foot in height. They are hardy perennials, their long- stemmed heads excellent for cutting. Returning to Chattanooga through Fort Payne, Alabama, we collected seed of Smilax hispida; Ruellia parviflora, a member of the Acanthus Family with short- lived deep- lavender flowers; and Ilex longipes. At Chattanooga we collected seed of Porteranthus stipu-latus. Going back down into Georgia, we crossed again through the mountains into Blairsville from the west, collecting en route seed of Helianthus angustifolius, a handsome species, with numerous narrow leaves and many deep orange- yellow heads with black disks; Mimulus ringens, Steironema hybrichuu, Viburnum nudum, Smilax laurifolia, an evergreen species with leathery leaves, much used for holiday decoration; Lobelia amoena; and Decumaria barbara, our native climbing hydrangea. We returned to North Carolina at Murphy and then returned to Asheville via Franklin, obtaining seed of an Oligoneuron which previously had not been ripe. The Oligoneurons are related to the goldenrods, but they have flat- topped, wide- spreading heads of flowers, and very large, dock- like leaves. At Asheville we collected seed of Helianthus giganteus and of Falcata Pitcheri, a relative of the hog- peanut, F. comosa, but with shaggy brown hairs and rose-purple flowers. Accompanied again by Mr. and Mrs. Clement, we made a trip into the Pisgah National Forest to explore Looking- glass Rock, altitude 4,000 feet, collecting on its summit seed of Eubotrys recurva, a relative of the Andromedas; Clethra acuminata, a tree- relative of the white alder; Tsuga caroliniana, the finest of the hemlocks, and Finns pungens. Then ascending Mount Pisgah, altitude 5,749 feet, we experienced the best collecting of any one spot, obtaining on that moun- i37 tain seeds of Aristolochia macrophylla; a large purple- flowered Penstemon; Viorna Viorna; Houstonia purpurea, a bluet relative with large ovate leaves and purplish flowers; Hydatica petiolaris, Heuchera villosa, Pieris floribunda, an albino of Aster macro-phyllus, Rhododendron minus, Galax aphylla, Clethra acuminata, and a large- headed Heliopsis which may be a new species. At Asheville we visited Mr. C. D. Beadle, superintendent of the Biltmore Estate, who allowed us to collect seed of Hales'ia diptera, FIGURE 7. The east face of Table Rock, showing the 500- foot summit cliff of this spectacular peak. On the summit ledges were found Leiophyl-lum Hugeri, Hudsonia montana, and Xerophyllum asphodeloides. the rarest of the silverbells, and Ratibida columnaris from his cultivated plants. After making our final shipments, we bade Asheville goodbye and started our return trip, going east to Marion, collecting en route seed of Lobelia puberula, a tall species with dark blue flowers. From Marion we went up the Linville River along a mountain-top road to Linville Falls, collecting seed of Chamacliriuiu luteum, a lily relative known as blazing star or devil's bit, with a long spike of cream- colored, feathery flowers; and Therofon aconitifolium, 138 growing on wet, dripping rock ledges, a saxifrage with foliage like that of aconite. Crossing the Linville River, we went down the other side and took a badly wrecked road in to the foot of Table Rock, a spectacular peak 3,909 feet in altitude with a 500- foot pinnacle of stone seated on its summit. As this peak and a few neighboring ones were the only locality for Leiophyllum Hugeri, we ascended it and obtained seeds of that plant as well as of Xerophyllum aspho-deloides, a lily relative with leaves like pine needles and a long-stalked head of feathery white flowers. We then went on northeast to Blowing Rock, on whose cliffs at 3,800 feet altitude we collected seed of Paronychia argyrocoma, and Liatris Helleri, a species of blazing- star which is rarely over six inches tall in the wild state. Near Boone we collected seed of Aster Curtisii, a tall species with large light blue- purple heads. Going back through Virginia, we ascended the Peaks of Otter, altitude about 4,000 feet, where we obtained seed of Spiraea corym-bosa, Kneiffia glauca; Coreopsis verticillata, a species with cosmoslike foliage; Campanula divaricata, and a form of Liatris spicata, different from that of our previous collection. Spiraea corymbosa is a species with flat- topped heads of flowers, the plants rarely growing over a foot tall. Kneiffia glauca is the best of the day-blooming evening- primroses, being a perennial with numerous stems bearing large bright yellow flowers, the stems averaging 12- 15 inches in height. Campanula divaricata is an attractive species, growing from six inches to two feet tall in the wild state, and in almost any soil in sun or light shade. The leafy stem is very loosely much- branched, the branches spreading, ultimately drooping, well covered with nodding blue flowers about J4 inch in diameter, the color being deeper in shady moist places than in sun, but the growth better in the sun. Continuing north, we went out to Clifton Forge for seed of the large- flowered Oenothera argillicola we had seen there. After obtaining it, we went up to Hot Springs, near which we collected seed of Hypericum prolificum and Helenium latifolium. At Millboro we collected seed of Clematis viticaulis, this being its only known locality, and of Eriogonum Alleni, Asclepias tuberosa, and Scutellaria ovata. 139 Returning to the Cacapon River bluffs near Largent, West Virginia, we obtained seeds of Oenothera argillicola; Cunila origan-oides, a perennial mint with masses of tiny rosy- lavender flowers; Houstonia longifolia, Liatris scariosa, and Sorghastrum nutans, an ornamental grass with yellow flowers and seeds. Near Berkeley FIGURE 8. The summit cliffs of Table Rock. The dark patches are clumps of Leiophyllum Hugeri, the taller growth is Rhododendron minus and a few stunted hickories and wild cherries. Springs, we collected seed of Ipomoea Nil, Asclepias incarnata, and Ipomoea pandurata. We then returned to New York by way of Harrisburg, Pennsylvania, having traveled 5,766 miles in our eight weeks of absence, and collected, besides a few plants, about 375 lots of seeds. EDWARD J. ALEXANDER. 140 HYBRIDS BETWEEN THE NECKLACE COTTONWOOD AND THE LARGE- LEAVED ASPEN The two species Popidus balsamifera virginiana Sarg. and P. grandidentata Michx. belong to two very distinct groups of poplars and present decided contrasts in various characteristics. P. balsamifera virginiana is a cottonwood, having glabrous, somewhat fragrant, deltoid to ovate- deltoid leaves with acuminate apex, a truncate to slightly cordate or occasionally abruptly cuneate base, and crenately serrate margin. The winter buds are very resinous, viscid, and aromatic. Trees of this species, which is known as the necklace cottonwood, grow rather rapidly while young and they may become very large trees, with widely spreading branches. The Lafayette tree of historical associations, located near Geneva, N. Y., which is of this species and variety, has a trunk over 20 feet in circumference and a crown about 100 feet tall. This tree is perhaps 200 years old, for it was a large tree when General Lafayette visited the country more than ioo years ago. Other trees of this variety, of nearly the same age and size, are to be found at various localities in New York State. P. grandidentata belongs in the aspen group, and is characterized by semi- orbicular to broad- ovate leaves with short- pointed apex, a rounded to abruptly cuneate, or rarely truncate base, and coarsely repand- dentate margin. The younger leaves and petioles of " this species are covered with a white tomentum. The winter buds are pubescent and not resinous, viscid, or aromatic. The largest trees of this species seldom reach a trunk diameter of two feet. There is also a very marked difference between the two species in their ability to root from cuttings: cuttings of P. balsamifera virginiana root fairly well, whereas cuttings of P. grandidentata root very poorly, usually much less than one per cent, under identical nursery conditions. In 1926, in connection with a project in breeding populars, 1 seeds were obtained on a female tree of P balsamifera virginiana after controlled pollination with pollen of P- grandidentata, and from this seed 178 seedlings were grown. 1 The breeding of forest trees for pulp wood. By A. B. Stout, Ralph H. McKee, and E. J. Schreiner. Jour. N. Y. Bot. Garden 28: 49- 63. 1927. H i FIGURE I. Hybrids of Popidus balsamifera virginiana x P. grandidentata, two years old from seed; snowing inherent differences in vigor, and a decided resemblance to the pollen parent. Description of the hybrids. Leaves: mostly broad- ovate, varying from almost semi- orbicular to rather narrow- ovate, dark green above, not aromatic; apex usually somewhat acuminate, varying from acute, sharp- pointed to narrowly acute, points not entire; base usually somewhat cordate, slightly rounded, varying from strongly cordate to little or not at all cordate; margin crenately serrate, incurved teeth glandular, individual seedlings varying in fineness and sparseness of the crenate serrations; texture thin, firm; younger leaves densely pubescent or tomentose. Stems: terete, tips of most vigorous shoots very slightly angled, at first coated with a thick hoary deciduous tomentum, later becoming olive- brown to olive- gray; lenticels oblong to linear, on older wood practically circular, usually orange- colored. Winter buds: terete, 142 rather broadly ovoid, acute; individual seedlings vary in narrowness of buds and extent to which they are appressed; buds of some seedlings slightly out- curved; color chestnut- brown; seedlings vary in amount of pubescence on buds but none are glabrous, and they are not resinous, viscid, or aromatic. The 178 sister hybrids of this series were very uniform in respect to the general characters of leaves, buds, and stems. There was, however, much difference in vigor of growth; some of them were weak and very slow- growing, as shown in FIGURE I. Brief mention has been made of these hybrids and one is illustrated in a recent report on the entire breeding project with poplars. 2 FIGURE 2. Showing large leaf of sucker branch, smaller leaf typical of old trees, and twigs of ( 1) Populus balsamifera virginiana and ( 2) P. grandidentata, and ( at 3) leaf and twig of one of the hybrids. Comparisons with parents ( see FIGUKE 2). The leaves of the hybrids resemble the leaves of P grandidentata in shape, apex, texture, color, and tomentum. The leaf base is more or less intermediate between P. grandidentata and P. balsamifera virginiana; the leaf margin resembles that of the leaves on vigorous branches of P balsamifera virginiana but is even more finely serrate. The stems resemble those of the P grandidentata in shape, color, tomentum, and appearance of the lenticels. The winter buds of the hybrids are more like those of P grandidentata in shape, pubes- 2 Stout, A. B., and Schreiner, E. J. Results of a project in hybridizing populars. Jour, of Heredity 24: 216- 229. 1933- 143 cence, and absence of the aromatic, viscid, or resinous character. The growth thus far made by the hybrids indicates that the trees will resemble the pollen parent ( P. grandidentata) in appearance. Thus in only a few of the characters is there definite influence of the seed parent; there is a decided dominance for nearly all the characters of the pollen parent. The best of these hybrids are less vigorous in growth than seedlings or plants grown from cuttings of the seed parent. Most, if not all of them, appear to be less vigorous than plants of the pollen parent. They are much less vigorous than many hybrids of other crosses in the genus Populus. None of them has merit for use in reforestation and it is doubtful if any have merit as shade trees. The writers have found no references to hybrids between the two species Populus balsamifera virginiana and P. balsamifera, either of wild origin or of experimental production. A. B. STOUT, New York Botanical Garden. E. J. SCHREINER, Oxford Paper Company. TWO IMPORTANT NEW BOOKS FOR GARDENERS L. H. Bailey and M. G. Kains— as different in style of writing as two horticulturists could hope to be— have each lately produced a new book which in its way seems quite indispensable to the gardener who wishes to know the what, how, when, and why of all that he does with his plants. Mr. Kains's volume, 1 " Modern Guide to Successful Gardening," treats each subject particularly from the point of view of methods to be used in cultivation. The first 150 pages, approximately, deal with flowers, shrubs, vines, and trees; the next 100 with fruits and vegetables, and the last, almost 100 pages, with planning and carrying out practical work in the garden. The emphasis on fruits and vegetables seems a trifle strong, especially when one considers that strawberries are given a whole chapter, while iris is merely mentioned in one line of one appendix; geraniums are not mentioned at all— unless in some other undis- 1 Kains, M. G., Modern Guide to Successful Gardening. Pp. 370, illus. Greenberg, New York. 1934. $ 2.50. 144 covered line— and peonies, asters, and delphiniums are given no greater attention. But food plants have a powerful hold on many gardeners, and the book is really amazingly complete for a volume of its size. Each one of its 49 chapters, prefaced by an amusing verse and an instructive sentence, both quoted, deals with some subject that really is of prime importance for the gardener to know. The text is clear and entertaining, and is amplified by drawings, diagrams, and tables, which are further amplified by the long appendices, listing members of some two dozen groups of plants, from roses to vegetables that will withstand frost, and giving some valuable information about each. Dr. Bailey2 takes up the culture of nearly a thousand species of plants in alphabetical order, from Abutilon to Zinnia, listing both common and scientific names for each, and treating each subject under the name most commonly used. Instructions are brief, necessarily, but adequate for the average gardener's use. Informative lists of perennials, annuals, vines, ground- covers, and such groups are offered, and fairly detailed directions are given for developing rock, water, and window gardens, for propagating, fertilizing, and pruning, and similar essential operations, all concise and practical. It is strange that neither of these new books, the one by its title a " modern" guide, and the other by virtue of its authorship presumably the latest word in horticulture, mentions one of the new California plants which are becoming increasingly popular in rock gardens and borders. The names Brodiaea, Calochortus, Lewisia, and Camassia, for example, appear in neither. South African plants are almost as seriously neglected. Ursinia ane-thoides is not mentioned; Dimorphotheca is barely cited in Dr. Bailey's book, and Felicia has won a place in neither. The list might perhaps be extended, but unnecessarily. Outside of this lack, both books have outstanding value for any gardener's use. CAROL H. WOODWARD. 2 Bailey, L. H., Gardener's Handbook. Pp. 292, illus. Macmillan, New York. 1934. $ 3.00. PUBLICATIONS OF THE NEW YORK BOTANICAL GARDEN Journal of The New York Botanical Garden, monthly, containing notes, news, and non- technical articles. Free to members of the Garden. To others, 10 cents a copy; $ 1.00 a year. Now in its thirty- fifth volume. Mycologia, bimonthly, devoted to fungi, including lichens; $ 5.00 a year. Now in its twenty- sixth volume. Official organ of the Mycological Society of America. Addisonia, semi- annual, devoted exclusively to colored plates accompanied by popular descriptions of flowering plants; eight plates in each number, thirty- two in each volume. Subscription price, $ 10.00 a volume ( two years). [ Not offered in exchange.] Now in its eighteenth volume. Bulletin of The New York Botanical Garden, containing reports of the Director- in- Chief and other official documents, and technical articles embodying results of investigations. Free to all members of the Garden; to others, $ 3.00 per volume. Now in its fourteenth volume. North American Flora. Descriptions of the wild plants of North America, including Greenland, the West Indies, and Central America. Planned to be completed in 34 volumes. Roy. 8vo. Each volume to consist of four or more parts. 73 parts now issued. Subscription price, $ 1.50 per part; a limited number of separate parts will be sold for $ 2.00 each. [ Not offered in exchange.] Memoirs of The New York Botanical Garden. Price to members of the Garden, vols. I- VI, $ 1.50 per volume; to others, $ 3.00. Vol. VII, $ 2.50 to members; to others, $ 5.00. Vol. I. An Annotated Catalogue of the Flora of Montana and the Yellowstone Park, by Per Axel Rydberg. ix + 492 pp., with map. 1900. Vol. I I . The Influence of Light and Darkness upon Growth and Development, by D. T. MacDougal. xvi + 320 pp., with 176 figures. 1903. Vol. I I I . Studies of Cretaceous Coniferous Remains from Kreischer-ville, New York, by A. Hollick and E. C. Jeffrey, xiii + 138 pp., with 29 plates. 1909. Vol. IV. Effects of the Rays of Radium on Plants, by Charles Stuart Gager. viii + 478 pp., with 73 figures and 14 plates. 1908. Vol. V. Flora of the Vicinity of New York: A Contribution to Plant Geography, by Norman Taylor, vi + 683 pp., with 9 plates. 1915. Vol. VI. Papers presented at the Celebration of the Twentieth Anniversary of The New York Botanical Garden, v i i i + 594 pp., with 43 plates and many text figures. 1916. Vol. VII. Includes New Myxophyceae from Porto Rico, by N. L. Gardner; The Flower Behavior of Avocados, by A. B. Stout; Descriptions of New Genera and Species of Plants Collected on the Mulford Biological Exploration of the Amazon Valley, 1921- 1922, by H. H. Rusby; and The Flora of the Saint Eugene Silts, Kootenay Valley, British Columbia, by Arthur Hollick. viii + 464 pp., with 47 plates, 10 charts, and II text- figures. 1927. Brittonia. A series of botanical papers. Subscription price, $ 5.00 per volume. Now in its first volume. Contributions from The New York Botanical Garden. A series of technical papers written by students or members of the staff, and reprinted from journals other than the above. Price, 25 cents each. $ 5.00 per volume. In the fourteenth volume. Flora of the Prairies and Plains of Central North America, by P. A. Rydberg. 969 pp. and 601 figures. Price, $ 5.50 postpaid. THE NEW YORK BOTANICAL GARDEN Bronx Park, New York, N. Y. G E N E R A L I N F O R M A T I ON Some of the leading features of The New York Botanical Garden are: Four hundred acres of beautifully diversified land in the northern part of the City of New York, through which flows the Bronx River. A native hemlock forest is one of the features of the tract. Plantations of thousands of native and introduced trees, shrubs, and flowering plants. Gardens, including a new rock garden, a large rose garden, a perennial border, small model gardens, and other types of plantings. Greenhouses, containing thousands of interesting plants from America and foreign countries. Flower shows throughout the year— in the spring, summer, and autumn displays of daffodils, tulips, lilacs, irises, peonies, roses, lilies, water- lilies, dahlias, and chrysanthemums; in the winter, displays of greenhouse-blooming plants. A museum, containing exhibits of fossil plants, existing plant families, local plants occurring within one hundred miles of the City of New York, and the economic uses of plants. An herbarium, comprising more than 1,700,000 specimens of American and foreign species. Exploration in different parts of the United States, the West Indies, Central and South America, for the study and collection of the characteristic flora. Scientific research in laboratories and in the field into the diversified problems of plant life. A library of botanical literature, comprising more than 43400 books and numerous pamphlets. Public lectures on a great variety of botanical topics, continuing throughout the year. Publications on botanical subjects, partly of technical, scientific, and partly of popular, interest. The education of school children and the public through the above features and the giving of free information on botanical, horticultural and forestral subjects. The Garden is dependent upon an annual appropriation by the City of New York, private benefactions, and membership fees. It possesses now nearly two thousand members, and applications for membership are always welcome. The classes of membership are: Benefactor single contribution $ 25,000 Patron single contribution 5,000 Fellow for Life single contribution 1,000 Member for Life single contribution 250 Fellowship Member annual fee 100 Sustaining Member annual fee 25 Annual Member annual fee 10 Contributions to the Garden may be deducted from taxable incomes. The following is an approved form of bequest: / hereby bequeath to The New York Botanical Garden incorporated under the Laws of New York, Chapter 285 of 1891, the sum of . Conditional bequests may be made with income payable to donor or any designated beneficiary during his or her lifetime. All requests for further information should be sent to T H E N E W YORK BOTANICAL GARDEN BRONX PARK, NEW YORK, N. Y.
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Contributor | New York Botanical Garden |
Date | 1934-06 |
Description-Table Of Contents | Hardiness in Plants; New Roses from Persia; Report of the Southern Appalachian Expedition—II; Hybrids between the Necklace Cottonwood and the Large-leaved Aspen; Two Important New Books for Gardeners. |
Format | application/pdf |
Format-Extent | 51 v. : ill. ; 25 cm. |
Identifier | 0885-4165 |
Language | eng |
Publisher | Bronx : New York Botanical Garden, 1900-1950 |
Relation-Is Part Of | Journal of the New York Botanical Garden : v. 1, no. 1-v. 51, no. 612 |
Relation-IsVersionOfURI | http://opac.nybg.org/record=b1104879 |
Rights | http://www.nybg.org/library/ |
Subject | Plants--Periodicals; Gardening--Periodicals; Plants, Cultivated--Periodicals; New York Botanical Garden--Periodicals. |
Title | Journal of the New York Botanical Garden |
Volume, Number | Vol. 35, no. 414 |
Type | text |
Transcript | VOL. XXXV JUNE, 1934 No. 414 JOURNAL OF THE NEW YORK BOTANICAL GARDEN HARDINESS IN PLANTS HENRY TEUSCHER NEW ROSES FROM PERSIA REPORT OF THE SOUTHERN APPALACHIAN EXPEDITION— II EDWARD J. ALEXANDER HYBRIDS BETWEEN THE NECKLACE COTTONWOOD AND THE LARGE- LEAVED ASPEN A. B. STOUT TWO IMPORTANT NEW BOOKS FOR GARDENERS CAROL H. WOODWARD PUBLISHED FOR THE GARDEN AT LIME AND GREEN STREETS, LANCASTER, PA. THE SCIENCE PRESS PRINTING COMPANY Entered at the post- office in Lancaster, Pa., as second- class matter. Animal subscription $ 1,00 Single copies 10 cents Free to members of the Garden THE NEW YORK BOTANICAL GARDEN BOARD O F MANAGERS I. ELECTIVE MANAGERS Until 1935: L. H. BAILEY, THOMAS J. DOLEN, MARSHALL FIELD, MRS. ELON HUNTINGTON HOOKER, KENNETH K. MACKENZIE, JOHN L. MERRILL ( Vice- president and Treasurer), and H. HOBART PORTER. Until 1936: ARTHUR M. ANDERSON, N. L. BRITTON, HENRY W. DE FOREST ( President), CLARENCE LEWIS, E. D. MERRILL ( Director and Secretary), HENRY DE LA MONTAGNE, JR. ( Assistant Treasurer & Business Manager), and LEWIS RUTHERFURD MORRIS. Until 1937: HENRY DE FOREST BALDWIN ( Vice- president), GEORGE S. BREWSTER, CHILDS FRICK, ADOLPH LEWISOHN, HENRY LOCKHART, JR., D. T. MACDOUGAL, and JOSEPH R. SWAN. I I . EX- OFFICIO MANAGERS FIORELLO H. LAGUARDIA, Mayor of the City of New York. ROBERT MOSES, Park Commissioner. GEORGE J. RYAN, President of the Board of Education. III. APPOINTIVE MANAGERS A. F. BLAKESLEE, appointed by the Torrey Botanical Club. R A. HARPER, SAM F. TRELEASE, EDMUND W. SINNOTT, and MARSTON T. BOGERT, appointed by Columbia University. DIRECTOR EMERITUS N. L. BRITTON, P H . D., SC. D., LL. D. GARDEN STAFF E. D. MERRILL, SC. D Director MARSHALL A. HOWE, P H . D., SC. D Assistant Director H. A. GLEASON, P H . D Head Curator JOHN K. SMALL, PH. D., SC. D Chief Research Associate and Curator A. B. STOUT, P H . D Director of the Laboratories FRED J. SEAVER, P H . D., SC. D Curator BERNARD O. DODGE, P H . D Plant Pathologist FORMAN T. MCLEAN, M. F., P H . D Supervisor of Public Education JOHN HENDLEY BARNHART, A. M., M. D... Bibliographer and Admin. Assistant PERCY WILSON Associate Curator ALBERT C. SMITH, P H . D Associate Curator SARAH H. HARLOW, A. M Librarian H. H. RUSBY, M. D Honorary Curator of the Economic Collections FLEDA GRIFFITH Artist and Photographer ROBERT S. WILLIAMS Research Associate in Bryology E. J. ALEXANDER Assistant Curator and Curator of the Local Herbarium HAROLD N. MOLDENKE, P H . D Assistant Curator CLYDE CHANDLER, A. M Technical Assistant ROSALIE WEIKERT Technical Assistant CAROL H. WOODWARD, A. B Editorial Assistant THOMAS H. EVERETT, N. D. HORT. Horticulturist HENRY TEUSCHER, HORT. M Dendrologist G. L. WITTROCK, A. M Docent ROBERT HAGELSTEIN Honorary Curator of Myxomycetes ETHEL ANSON S. PECKHAM . . Honorary Curator, Ins and Narcissus Collections WALTER S. GROESBECK Clerk and Accountant ARTHUR J. CORBETT Superintendent of Buildings and Grounds JOURNAL OF The New York Botanical Garden VOL. XXXV JUNE, 1934 No. 414 HARDINESS IN PLANTS1 As long as I have been engaged in horticulture, I have been interested in the problems pertaining to hardiness in plants. Anxious from the first to familiarize myself with the peculiarities of the plant material with which I was working, I began taking local notes on the manner in which various plants survived the winter. That seemed simple enough. But the second year, when I set out to verify and complete my notes, I found that plants which I had marked down as hardy during the previous severe winter appeared to be tender, though the season had been much milder. I concluded that my observations had been at fault, and continued taking notes, extending my observations from the Imperial Parks at Potsdam to the Botanical Garden at Dahlem- Berlin. But after three or four winters my notes had become so complicated and contradictory that I commenced to suspect that temperature was not alone the deciding factor in the hardiness of plants. My view was confirmed by many experienced gardeners whom I consulted. It became apparent that the condition in which a plant entered the winter— which in turn depended upon the preceding growing season, as well as on local conditions— was of at least as much, if not of greater, importance. In the twenty years since then, the subject has never ceased to absorb my attention. Out of the innumerable strange instances of hardiness which I observed ( some of which I shall cite later on), I have learned, in particular, two things: 1 A lecture given before the Conference of the Scientific Staff and Registered Students of The New York Botanical Garden, on April 12, 1934. 121 First: That it is possible to grow a great many more plants out of doors than is generally believed, provided that we do not give up in despair after the first failure but rather follow the plant closely through its life cycle for several years and adjust gradually the conditions under which it grows until they are most favorable to bring about hardiness. The first trial has to be based on a guess, and it is a method of hit or miss, but this is still the best we can do. After a few successes we will find that it will become easier and ever easier to guess right from the start. Second: I have learned that it is frequently quite impossible to say of a plant outright, " It is hardy." I have learned to say instead, " It can be grown successfully outdoors in this vicinity," which implies that it is hardy provided that conditions and treatment are right. In outlining what constitutes and what influences hardiness I shall commence with the results of the investigations of the physiologists, then quote the observations of the practical horticulturist and gardener, and conclude with a preliminary report on the injuries which have resulted from this past severe winter. The physiologists, in general, agree that winter hardiness is a very indefinite and complex matter, depending on numerous widely different factors which often exclude one another, and that it is not necessarily identical with frost resistance. The resistance to severe dehydration, the ability to remain dormant through prolonged warm spells in the winter, and the capacity to stop and start growth at the most opportune times in autumn and spring, which means to be in tune with the changing seasons, are at least as important as the ability to withstand low temperatures. What actually is the life- sustaining factor at very low temperatures and what is the quality that renders one plant more resistant than another are still very much of a mystery, even to physiologists. The theory advanced by the Russian investigator, Govorov, that hardy plants fall into a state of anabiosis, during which respiration is almost suspended, certainly is interesting. He contends that in this state of anabiosis the hardy plant does not suffer from the deficiency of oxygen in the soil which, according to his opinion, is the main cause of death for non- hardy plants in the winter. Similar conditions of suspended life occur also in animals and even in human beings, as we all know, but in what this condition actually 123 consists, and what brings it about, we cannot expect to be able to explain until we have solved the eternal mysteries of life and death. What we do know, thanks to the research work of the plant physiologists of the world, is what goes on in the plant cell when it freezes and. when it dies from freezing; to a certain extent, also, what goes on in a cell which freezes but survives. From these researches it appears that when plant tissue is subjected to a sufficiently low temperature, ice is formed, in particular in the intercellular spaces toward which, with further lowering of the temperature, more and more water is drawn, first from the cell sap and finally also from the plasma. The physiologists are divided as to what causes the death of the plasma, if the temperature sinks too low. Some of them insist that death results from the chemical influence of the increased concentration of salts and acids on the colloids of the plasma, while others maintain that the plasma is injured mechanically by the compression of the cells caused by the ice crystals which accumulate in the intercellular spaces. I am not a judge, since I am not a plant physiologist and have never investigated these conditions, but it seems to me quite possible that both parties are right, and that either type of injury, perhaps even both simultaneously, may result, depending upon the kind of plant and the condition of the plant which is used for the experiment. In either case it seems to be important for the plant cell, in order to increase its hardiness, to decrease its content of free water which may be frozen, and this is, quite apparently, what actually happens. A method to use the condensation of the cell sap or the decreased free water content of the hardened cell, respectively, in order to measure the degree of hardiness of a plant, was first suggested by Newton, who experimented with different varieties of winter wheat. Pressing out the sap of uninjured leaves under pressure of 400 atmospheres, he found that hardened leaves gave up only an insignificant amount of sap, while tender leaves gave up their sap easily. In the protoplasm the water is bound by hydrophilic colloids which are formed during the process of hardening and which, to a certain extent, seem to prevent fatal dehydration. In the cell sap, water may be bound, for instance, by an increased sugar content. A concentrated sugar solution gives water off only slowly, 124 and the slower, the more concentrated it becomes. It seems, however, that the importance of the protective role of the sugars has been considerably overstressed. In the dormant, or, as the gardener says, ripened twigs of trees in the fall, there is noticeable a very marked condensation of the cell sap and a decrease in free water content, but there is no sugar. The cells of these dormant twigs are filled with starch. Sugar is not formed in these cells until after they have been subjected to low temperatures, and the sugar content gradually increases during the winter. In this connection I wish to mention the extremely interesting observations of Coville, who experimented at first with blueberries, but later also with many other plants, and who suggests quite a different role for the sugars in the cells of wintering plants ( as reported in the Journal of Agricultural Research, Oct., 1920). For purposes of cross- fertilization Coville brought some blueberry plants into a greenhouse with favorable growing temperature at the end of the summer. These plants refused to continue their growth, however. They gradually dropped their leaves and went into a state of complete dormancy, remaining in this condition in spite of a greenhouse temperature which in spring and summer would have kept the plants in luxuriant growth. When finally towards the end of winter other plants were brought in from the field, these latter at once burst into leaf and flower, while the indoor plants remained dormant as before. At first it was supposed that the plants needed to be frozen to start them into growth, but a single freezing proved ineffective. Then it was found that the dormant plants would start into growth without any freezing whatever. It was necessary only that they be subjected to a period of prolonged chilling, usually two or three months, at a temperature a few degrees above freezing. Plants kept continuously warm, without chilling, in some instances remained dormant for a whole year. In the course of his observations Coville reached the conclusion that the transformation of the stored starch into sugar which occurred in the dormant twigs during the period of chilling was the vital factor, and suggested that the development of high osmotic pressure caused by the concentrated sugar solutions in the cells might be the mechanism which started the plants into growth. In explanation of the formation of sugar during the process of 125 chilling, he advanced the theory that the starch grains stored in the cells of the plant are at first separated by the living cell membranes from the enzyme that would transform the starch into sugar, but when the plant is chilled the vital activity of the cell membrane is weakened, so that the enzyme leaks through it, comes in contact with the starch, and turns it into sugar. In view of these interesting suggestions it would be of vital importance for truly hardy plants to be able to remain dormant during prolonged spells of warm weather in February, after several months of chilling, and in spite of the rich sugar content of their cells. An explanation for this ability of many plants has not been advanced so far. The most interesting paper on the problem of hardiness in plants which I have come across, and to which Dr. Stout directed my attention, is one by the Russian, N. A. Maximow, entitled, " Internal Factors of Frost and Drought Resistance in Plants," published in 1929 in the Journal " Protoplasma." Maximow seems to have been the first to recognize the analogy between frost and drought resistance, and he gives an excellent review of the present state of both questions. From his own investigations, as well as by an extensive literature which he cites, he points out that in both cases the resistance lies in the capacity of the protoplasm to withstand the dehydrating influence of a direct or indirect deprivation of water, but warns at the end that this analogy must not be understood as identity. As we all know, plants resistant to drought are not always also frost resistant, and the capacity to resist low temperatures is not always accompanied by the capacity to endure severe desiccation. The controversy concerning the difference to a frozen plant, as to whether it is thawed out quickly or slowly, is perhaps not yet altogether settled. Molisch, who has experimented with a great many different plants, reached the conclusion that a plant either is killed in the freezing or remains uninjured also when thawed out quickly. This is in contradiction with the claim of all experienced gardeners. However, one has to consider that Molisch carried out his experiments in the laboratory while the gardener is dealing with plants in the open, where the drying effect of wind and sun is frequently the actual cause of injury during the process of thawing. The shading or sprinkling with water of frozen plants 126 in the early morning, which the gardener claims he does in order to slow down the thawing- out process, really serves mainly to prevent undue evaporation. Some exceptional cases where quick thawing actually proved injurious while slow thawing saved the tissue ( as, for instance, in the case of the leaves of Agave americana and flower buds of apple, which Molisch mentions) have not been explained as yet. The so- called " burning" of evergreen leaves and " sunscald" on tree trunks or twigs is also in reality a drying out. The tissues struck by the sun are unevenly warmed up, and the water which has been drawn out of the cells by the formation of ice is more quickly evaporated than it can be replaced, since the water- carrying vessels lower down in the tissue remain cold much longer and respond only sluggishly to the sudden demand. What causes and influences dormancy, or, as the gardener says, " ripening" of the wood, is not by any means perfectly clear. To a considerable extent it consists, undoubtedly, in an acquired habit and forms a part of the normal life cycle of a plant, most conspicuous in the plants of northern latitudes. The physiologist, as I said, admits that hardiness in plants is a very complex problem. The gardener does not always realize that, and the layman still more is frequently confused by the injury or the death of a plant which occurs— or seemingly occurs— in the winter, but which has nothing to do with hardiness. I have in mind, in particular, conifers and other evergreens which have suffered from severe drought during the summer. They are frequently already in a hopeless condition in the fall, though they do not show it, or their balls may have become so dry that no autumn rain can wet them and the further dehydration caused by the frost may kill them. That is why it is justly recommended to water conifers in the fall, or at least to make sure that they do not go into the winter with a dry root system. Other normally hardy plants may enter the winter in a weakened condition from having been planted in unsuitable soil; sun- loving plants from having been planted in the shade, or shade- loving plants in the sun. High alpine plants, or plants from the far North which in their native habitat are able to endure much lower temperatures than we ever get, may succumb to a mild winter with us after they have been weakened by our very long growing season or by other climatic 127 factors which are beyond our control. Such plants usually are adapted to a long winter during which they are covered with snow, which holds an even temperature, then a sudden transition from winter to spring and a rather short summer during which they have to finish their growth. They are therefore inclined to start growth in the spring as soon as the first warm days have thawed out the ground, which frequently proves their undoing in cultivation in the lowland. The experienced gardener knows that the way he will bring his plants through the winter depends very much on how he has treated them during the growing season and that, in particular, the following mistakes in treatment, or faulty conditions, or other factors frequently result in winter injury of some sort or other, or may cause tenderness in normally hardy plants: i— Late cultivation of the ground, which induces late growth and may result in the production of tender, unripened wood. 2— Late fertilising or over- fertilizing, especially with nitrogen fertilizers, which also may cause late, tender growth. 3— Superabundance of moisture, especially in rich soil with poor drainage, which causes a lush watery growth, suffering easily from freezing. This condition seems to favor, in particular, injury to the flower buds. 4— Permitting the plants to suffer from drought in the summer, which may cause a check in growth and may induce the plant to start growing again in late fall. 5— Mulching with moisture- holding or air- excluding litter, which may easily lead to rotting of the crowns of perennials. 6— Permitting a smothering overgrowth of aggressive neighbors and removing this overgrowth during the autumn cleaning. 7— Wrong pruning, especially sharp summer pruning of vigorous growing plants, which results in late growth and unripened wood ( climbing roses). 8— Propagation by cuttings, which, at least with certain plants, may result in the absence of a taproot ( this has been observed in particular with Phlomis fruticosa). The claim of many nurserymen that certain evergreens are hardier when raised from cuttings than from seeds, is not supported by facts. Seeds obtained from commercial seed-houses frequently come from southern strains which are tender, while cuttings are taken from plants which survived in the vicinity where the nurseryman is located, therefore they represent a hardier strain. This is especially true of Thuja plicata and Chamaecyparis Lawsoniana. 128 9— Production of a heavy crop of fruits, especially with grapes and certain fruit trees. The plant apparently extends its energies to the maturation of the fruits at the expense of wood and bud maturity, with the consequence that many of the unripened twigs and buds suffer frost injury during the winter. A light crop or crop failure frequently results in the following year. 10— Individual inclination of the plant, which closely resembles what is termed " emotional makeup" in man. Many plants vary considerably in hardiness if raised from seeds, as I had occasion to observe in particular in a set of several hundred seedlings of Cornus Kousa at the Boyce- Thompson Arboretum. Similar variations I observed this spring on larger sets of seedling plants of Albizcia Julibrissin, Castanea crenata, Diospyros Lotus, Prunus cyclaminea, Pterocarya stenoptera, Rosa omeiensis pteracantlw, Stranvaesia Davidiana, and Cytisus scoparius. Of all of these, some plants were killed to the ground while others remained entirely, or almost, uninjured, yet they were growing side by side under absolutely identical conditions. 11— Exposure. Many shrubs which during the summer are benefitted by a southern exposure, suffer during the winter more or less severely on their southern side if not shaded. Others ( also young trees) suffer severe injury in southern exposure while they may pass through the winter with no, or with only slight, injury in western or even northern exposure, provided they are protected against north winds. 12— Wrong planting, too deep as well as too high. 13— Late fall planting. Perennials, especially fleshy- rooted kinds, should not be planted late. Well- established shrubs or trees withstand sudden cold spells much better than those which have been planted within the last year or two, since their far- spreading root system is better in balance with their yearly growth. 14— Spring planting of pot- bound plants, which therefrom get a late start and may not be able to send their roots down deep enough to withstand the winter. 15— Neglecting to lift, divide, and replant certain perennials at reasonable periods causes aging and weakening of the plant. Old plants which are past the prime of their life and are on the down grade are more easily injured in the winter than are younger plants. In certain woody plants, especially, the very young plant also is tender to a certain age. In some instances there appears to be even a difference in the re- 129 sistance of the flower buds between young shrubs and older specimens. 16— Planting of trees which had dried out in shipment, especially in the fall. Such trees may frequently be saved by a covering of trunk and branches with paraffin wax. 17— Planting in so- called frost holes. The most excellent and concise explanation of the condition termed " frost- hole" which I have found, is given in a leaflet of the Weather Bureau of the United States Department of Agriculture, entitled, " Frost, when to expect it and how to prevent injury therefrom," written by W. H. Hammon, Professor of Meteorology. It may suffice to quote here from this text, which says that: In clear, calm nights the air arranges itself in layers, according to its density. The heavier cold air rests on the ground and in the valleys flows down the slopes, accumu- - lating on the lowest point when it can drain away no further. Places where cold air may accumulate in this manner must naturally be avoided, since especially during the vital weeks from early April to the later part of May, the temperature may drop considerably lower in such a frost- hole than on the surrounding slopes. When, after a late spring frost, only the lower branches or buds are found injured on a shrub or young tree, while the upper parts remain intact, there is suspicion of conditions resembling'a frost- hole, or at least insufficient air drainage on that particular place. When, on the contrary, for instance on a Forsythia bush, only the lowermost branches flower, the chances are that superabundance of moisture, viz., poor drainage, lowered the frost resistance of the buds. The lower branches were probably protected by snow or through shading from the upper branches. To INCREASE HARDINESS Conditions which assist in bringing about or in increasing the hardiness of plants are in particular, of course, the opposite of the above. The importance of drainage, which causes a stockier, hardier growth, I shall have occasion to point out later by examples. A cover crop of rye, wheat, oats, barley, or buckwheat sown in the summer similarly induces earlier ripening and consequent hardier growth, by taking care of surplus moisture as well as of surplus fertilizer. Such cover crops are employed in particular in peach orchards. 130 Winter protection consists in most cases in a protection against winter sun, drying winds, and the violent fluctuations of temperature which this winter sun causes, rather than in a protection against cold. Wrapping up may easily be overdone and will then cause more harm than benefit. Shading with burlap, as is done for instance with boxwood, or covering with pine branches, is usually much more effective. The wrapping- up with oil- paper, as has been recommended recently for roses in popular gardening magazines, is a dangerous practice, since the oil- paper acts as a sun trap and the fluctuations of temperatures between day and night are much more extreme under the paper than outside. Mulching, that is, a covering of the ground around the plant with leaf mould or old, well- rotted manure, can be recommended particularly for all recently planted or young plants and for all types of evergreens. Recent investigations have proved that the roots of most conifers especially remain active and continue to grow all through the winter. Since they are frequently rather shallow-rooting, the benefit derived from a mulch, which prevents violent fluctuations of the temperature of the soil, becomes easily understandable. REPORT I am now coming to the report on damages which have resulted from this last severe winter, and you are undoubtedly prepared to hear a long and sad list of losses. However, I can give you the cheerful news that the damage is by no means as serious as one might have expected. Most of the plants which I shall enumerate as having been killed altogether will hardly be known to you as outdoor plants— with the exception, of course, of the hybrid tea roses which were killed in many places, especially in light soil and where they had not been protected in the usual manner by heaping soil around the base of the bushes. The great majority of those plants had simply been under test, and, though many of them had done extremely well during the last two or three winters, I was well aware that their hardiness was doubtful and that the first really severe winter might cause their loss. When assembling plants for a botanical collection one has to test every plant that seems to have the slightest chance to succeed, since it is impossible to know of such a plant how hardy or how i3i tender it may prove to be until it has been tried. Nor, as I said before, does one trial and failure ever tell a fair story. In the above outline I explained how many factors there are which influence hardiness in plants. Not until all means have been exhausted to bring about the most favorable conditions for a plant, can it, in fairness, be called tender. Furthermore, most of the plants which I have to list today as dead, or severely injured, were plants, three to four years old, which were still in very vigorous growth. I said before that such young plants are almost always more tender than older, well- established plants. Most of these plants, also, were growing in nursery rows where cultivation had been kept up all through the summer to control weeds. This also tends to produce lush, tender growth. HENRY TEUSCHER. ( The death notices of the winter of 1933— 34 w^ oe given in subsequent issues of the JOURNAL.) NEW ROSES FROM PERSIA Several plants of a native rose from Persia which is believed to be nowhere in cultivation in the United States have been received by The New York Botanical Garden and now are growing where their flowering can be watched, in order to check the identification. They were secured by Mrs. William H. Moore, of 4 East Fifty-fourth Street, New York, a member of the Corporation of the Garden, while on a trip in the Near East during the spring. A release from the Federal Horticultural Board, when Mrs. Moore returned to New York in May, made it possible for the Garden to receive the plants for cultivation. 132 REPORT OF THE SOUTHERN APPALACHIAN EXPEDITION— II ( Continued from the May issue) Turning our attention west, we went out to Newport, Tennessee, and then down to Sevierville, from there entering the Great Smoky Mountains. There we collected seed of Cebatha Carolina, the red moonseed, a vine bearing dense clusters of red berries; Aralia spinosa, Cimicifuga americana, and Senecio Rugelia, and plants of Stcllaria pubera, the largest- flowered of the chickweeds, not at all weedy and very attractive for a shaded spot in the rock- garden. Cimicifuga americana is a much more handsome plant than the common C. racemosa, having spikes of much larger flowers, not so stiffly erect, and much lower in height, averaging 2— 3 feet. Senecio Rugelia is an extremely rare plant, known from only four or five stations high up in the Great Smokies. It is very unlike a Senecio, having large leaves somewhat similar to Aster macrophyllus and flower stalks with only 1- 5 large drooping heads of smoky- cream-colored flowers. It is not of great beauty, but is interesting for those who desire great rarities or unusual members of a genus usually markedly different. It grows in deep, mossy humus under the light shade at the edge of hemlock and spruce forests. Coming back into North Carolina and entering the Nantahala Gorge, we collected plants of Cymophyllus Fraseri, a sedge with Billbergia- like leaves and long- peduncled heads of feathery cream-colored flowers. Here also we found one plant of an albino of Lobelia siphilitica. Then passing across the south end of the Great Smokies back into Tennessee, we collected seed of Coreopsis major Oemleri; also Uniola latifolia, a grass with drooping slender- branched sprays, the branches terminating in flattened, oval heads which become reddish-tinged in fall; Helenium tenuifolium, an annual species with very slender leaves ; and plants of Silene virginica. Going to Knoxville, we turned west, collecting, on the limestone bluffs of the Clinch River, seeds of Manfreda virginica, a relative of the agaves. Helenium poly phyllum, a perennial species about one foot tall with numerous brown- centered heads, was collected near Rockwood. In a river swamp several miles from Chattanooga, 133 we collected seeds of Batodendron arboreum, the tree- blueberry, with numbers of drooping white flowers; Steironema tonsum, a relative of the Lysimachias; Elephantopus tomentosus, a composite with large basal leaves and heads of lavender flowers; Callicarpa americana, much more handsome than the usual cultivated species but not quite hardy in the north; Scutellaria ovalifolia, and Rham��nus caroliniana. W^ SMSMMFMI SHMPJHE K^ t- j^ HKBg., '"-^ t l& OTtuHn iiSaloiii^ l Hffm> wn^ nn^ Bi^ i^ El:! ilBOffiHi aaJSyllHPi FIGURE 5. A portion of the colony of Pamassia asarifolia in Neel's Gap, Ga., showing a typical healthy growth of this plant. Turning west again, we went out to Tullahoma and back to Chattanooga, collecting along the way seeds of Cassia marilandica, a perennial growing 2- 3 feet tall, with terminal sprays of yellow flowers; Verbena angustifolia, with upright spikes of small, lavender flowers; Liatris squarrosa and Liatris microcephala; Eupatorium incarnation, a sprawling plant with rosy- lavender flowers; Chry-sopsts Nuttallii; Bradburya virginica, a sprawling vine with lavender- purple, pea- like flowers 1- 1^ 2 inches across; and a pink- flowered, narrow- leaved Rhexia. 134 Back at Chattanooga, we ascended Lookout Mountain and there collected seed of Silene rotundifolia and a species of Penstemon. This Silene has round- ovate leaves and bright red flowers. It usually grows under shelving rocks, where it reaches a height of 10- 12 inches. When in the open it is much lower. Going back into North Carolina at Murphy, we collected along the way seed of Leonotis nepetaefolia, an introduced rather weedy plant from South America ; Vernonia altissima, and Liatris spicata. Near the Tennessee- North Carolina line, we collected plants of an albino of Aster sur-culosus. Returning to Asheville, we took a run out to Chimney Rock, obtaining along the Broad River seeds of Helianthus tomentosus, a handsome species with large, lemon- yellow heads; and collecting on Chimney Rock Mountain seeds of Talinum teretifolium, a fine rock plant with slender, fleshy leaves and rosy- purple flowers; Opidaster australis, Rhododendron minus, Coreopsis pubescens, a Penstemon, Rudbeckia triloba, Lonicera flava, Trautvesseria caro-linensis, two species of Philadelphus, and three species of Heuchera. It might here be stated that the eastern Heucheras cannot compare with H. sanguinca in showiness of flower. Their charm lies in the foliage and in the rather delicate small flowers, usually in graceful panicles. Back at Asheville, Mr. Everett left the party and returned to New York by train. We then went down into South Carolina, collecting a few plants of Senecio Millefolium at Caesar's Head, and seed of Coreopsis major at Westminster. Then passing over into Georgia, we zigzagged through the mountains to Blairsville, collecting en route seeds of Rhynchosia erecta, a plant about one foot tall with close clusters of pea- like, yellow flowers in the leaf- axils; Galactia volubilis, a sprawling or low-climbing relative of the beans, with short spikes of purplish- pink flowers; Isopappus divaricatus, an annual composite with a much-branched spray of small yellow heads, which should prove useful for bouquet arrangement; Passiflora incarnata, the native passionflower; a dwarf Ilex, covered with large red berries, though scarcely a foot tall; and Morongia angustata, the sensitive- brier, a vine which runs on the ground, bearing mimosa- like heads of pink flowers. 135 In Neel Gap, south of Blairsville, we came across a large colony of Pamassia asarifolia, by far the finest we had yet seen. The dripping ledges in a small stream and around it were covered with thousands of plants, many of which were in full flower. Continuing down to Atlanta, we climbed Stone Mountain and collected seeds of Gymnolomia Porteri, a sunflower- like annual composite, rarely exceeding a foot in height; Coreopsis saxicola, and Amorpha virgata; this being the type locality for all three of FIGURE 6. The range of mountains in North Carolina containing Table Rock, the sharp pinnacle in the left distance. Here one views the summit cap on edge from the north. The peak in the right distance is Hawksbill, ioo feet higher than Table Rock. these plants. We found also an Aster which appears to represent an entirely new group in the genus. Going from Atlanta to Rome, we collected seed of Brauneria pallida and a Penstemon. At Rome we collected seed of two species of Philadelphus, one Amorpha, and Clitoria mariana, a semi-vine with pea- like, lavender flowers 1— 1^ 2 inches long. Then turning west to Gadsden, Alabama, we collected en route seed of Coreopsis tripteris, a very tall- growing species with brown- 136 centered heads; MarshalUa obovata, an Allium, Helianthus mollis, Rudbeckia fulgida, with intense orange- yellow rays; Berchemia scandens, a woody vine related to Rhamnus, with glossy leaves and black fruits; Amorpha tenncsscensis, and Vernonia fiaccidifolia. The Marshallias are a group of southeastern composites resembling the Centaureas in the appearance of the flower heads, which are very pale lavender or pinkish, but the leaves are mostly basal, and the plants average about a foot in height. They are hardy perennials, their long- stemmed heads excellent for cutting. Returning to Chattanooga through Fort Payne, Alabama, we collected seed of Smilax hispida; Ruellia parviflora, a member of the Acanthus Family with short- lived deep- lavender flowers; and Ilex longipes. At Chattanooga we collected seed of Porteranthus stipu-latus. Going back down into Georgia, we crossed again through the mountains into Blairsville from the west, collecting en route seed of Helianthus angustifolius, a handsome species, with numerous narrow leaves and many deep orange- yellow heads with black disks; Mimulus ringens, Steironema hybrichuu, Viburnum nudum, Smilax laurifolia, an evergreen species with leathery leaves, much used for holiday decoration; Lobelia amoena; and Decumaria barbara, our native climbing hydrangea. We returned to North Carolina at Murphy and then returned to Asheville via Franklin, obtaining seed of an Oligoneuron which previously had not been ripe. The Oligoneurons are related to the goldenrods, but they have flat- topped, wide- spreading heads of flowers, and very large, dock- like leaves. At Asheville we collected seed of Helianthus giganteus and of Falcata Pitcheri, a relative of the hog- peanut, F. comosa, but with shaggy brown hairs and rose-purple flowers. Accompanied again by Mr. and Mrs. Clement, we made a trip into the Pisgah National Forest to explore Looking- glass Rock, altitude 4,000 feet, collecting on its summit seed of Eubotrys recurva, a relative of the Andromedas; Clethra acuminata, a tree- relative of the white alder; Tsuga caroliniana, the finest of the hemlocks, and Finns pungens. Then ascending Mount Pisgah, altitude 5,749 feet, we experienced the best collecting of any one spot, obtaining on that moun- i37 tain seeds of Aristolochia macrophylla; a large purple- flowered Penstemon; Viorna Viorna; Houstonia purpurea, a bluet relative with large ovate leaves and purplish flowers; Hydatica petiolaris, Heuchera villosa, Pieris floribunda, an albino of Aster macro-phyllus, Rhododendron minus, Galax aphylla, Clethra acuminata, and a large- headed Heliopsis which may be a new species. At Asheville we visited Mr. C. D. Beadle, superintendent of the Biltmore Estate, who allowed us to collect seed of Hales'ia diptera, FIGURE 7. The east face of Table Rock, showing the 500- foot summit cliff of this spectacular peak. On the summit ledges were found Leiophyl-lum Hugeri, Hudsonia montana, and Xerophyllum asphodeloides. the rarest of the silverbells, and Ratibida columnaris from his cultivated plants. After making our final shipments, we bade Asheville goodbye and started our return trip, going east to Marion, collecting en route seed of Lobelia puberula, a tall species with dark blue flowers. From Marion we went up the Linville River along a mountain-top road to Linville Falls, collecting seed of Chamacliriuiu luteum, a lily relative known as blazing star or devil's bit, with a long spike of cream- colored, feathery flowers; and Therofon aconitifolium, 138 growing on wet, dripping rock ledges, a saxifrage with foliage like that of aconite. Crossing the Linville River, we went down the other side and took a badly wrecked road in to the foot of Table Rock, a spectacular peak 3,909 feet in altitude with a 500- foot pinnacle of stone seated on its summit. As this peak and a few neighboring ones were the only locality for Leiophyllum Hugeri, we ascended it and obtained seeds of that plant as well as of Xerophyllum aspho-deloides, a lily relative with leaves like pine needles and a long-stalked head of feathery white flowers. We then went on northeast to Blowing Rock, on whose cliffs at 3,800 feet altitude we collected seed of Paronychia argyrocoma, and Liatris Helleri, a species of blazing- star which is rarely over six inches tall in the wild state. Near Boone we collected seed of Aster Curtisii, a tall species with large light blue- purple heads. Going back through Virginia, we ascended the Peaks of Otter, altitude about 4,000 feet, where we obtained seed of Spiraea corym-bosa, Kneiffia glauca; Coreopsis verticillata, a species with cosmoslike foliage; Campanula divaricata, and a form of Liatris spicata, different from that of our previous collection. Spiraea corymbosa is a species with flat- topped heads of flowers, the plants rarely growing over a foot tall. Kneiffia glauca is the best of the day-blooming evening- primroses, being a perennial with numerous stems bearing large bright yellow flowers, the stems averaging 12- 15 inches in height. Campanula divaricata is an attractive species, growing from six inches to two feet tall in the wild state, and in almost any soil in sun or light shade. The leafy stem is very loosely much- branched, the branches spreading, ultimately drooping, well covered with nodding blue flowers about J4 inch in diameter, the color being deeper in shady moist places than in sun, but the growth better in the sun. Continuing north, we went out to Clifton Forge for seed of the large- flowered Oenothera argillicola we had seen there. After obtaining it, we went up to Hot Springs, near which we collected seed of Hypericum prolificum and Helenium latifolium. At Millboro we collected seed of Clematis viticaulis, this being its only known locality, and of Eriogonum Alleni, Asclepias tuberosa, and Scutellaria ovata. 139 Returning to the Cacapon River bluffs near Largent, West Virginia, we obtained seeds of Oenothera argillicola; Cunila origan-oides, a perennial mint with masses of tiny rosy- lavender flowers; Houstonia longifolia, Liatris scariosa, and Sorghastrum nutans, an ornamental grass with yellow flowers and seeds. Near Berkeley FIGURE 8. The summit cliffs of Table Rock. The dark patches are clumps of Leiophyllum Hugeri, the taller growth is Rhododendron minus and a few stunted hickories and wild cherries. Springs, we collected seed of Ipomoea Nil, Asclepias incarnata, and Ipomoea pandurata. We then returned to New York by way of Harrisburg, Pennsylvania, having traveled 5,766 miles in our eight weeks of absence, and collected, besides a few plants, about 375 lots of seeds. EDWARD J. ALEXANDER. 140 HYBRIDS BETWEEN THE NECKLACE COTTONWOOD AND THE LARGE- LEAVED ASPEN The two species Popidus balsamifera virginiana Sarg. and P. grandidentata Michx. belong to two very distinct groups of poplars and present decided contrasts in various characteristics. P. balsamifera virginiana is a cottonwood, having glabrous, somewhat fragrant, deltoid to ovate- deltoid leaves with acuminate apex, a truncate to slightly cordate or occasionally abruptly cuneate base, and crenately serrate margin. The winter buds are very resinous, viscid, and aromatic. Trees of this species, which is known as the necklace cottonwood, grow rather rapidly while young and they may become very large trees, with widely spreading branches. The Lafayette tree of historical associations, located near Geneva, N. Y., which is of this species and variety, has a trunk over 20 feet in circumference and a crown about 100 feet tall. This tree is perhaps 200 years old, for it was a large tree when General Lafayette visited the country more than ioo years ago. Other trees of this variety, of nearly the same age and size, are to be found at various localities in New York State. P. grandidentata belongs in the aspen group, and is characterized by semi- orbicular to broad- ovate leaves with short- pointed apex, a rounded to abruptly cuneate, or rarely truncate base, and coarsely repand- dentate margin. The younger leaves and petioles of " this species are covered with a white tomentum. The winter buds are pubescent and not resinous, viscid, or aromatic. The largest trees of this species seldom reach a trunk diameter of two feet. There is also a very marked difference between the two species in their ability to root from cuttings: cuttings of P. balsamifera virginiana root fairly well, whereas cuttings of P. grandidentata root very poorly, usually much less than one per cent, under identical nursery conditions. In 1926, in connection with a project in breeding populars, 1 seeds were obtained on a female tree of P balsamifera virginiana after controlled pollination with pollen of P- grandidentata, and from this seed 178 seedlings were grown. 1 The breeding of forest trees for pulp wood. By A. B. Stout, Ralph H. McKee, and E. J. Schreiner. Jour. N. Y. Bot. Garden 28: 49- 63. 1927. H i FIGURE I. Hybrids of Popidus balsamifera virginiana x P. grandidentata, two years old from seed; snowing inherent differences in vigor, and a decided resemblance to the pollen parent. Description of the hybrids. Leaves: mostly broad- ovate, varying from almost semi- orbicular to rather narrow- ovate, dark green above, not aromatic; apex usually somewhat acuminate, varying from acute, sharp- pointed to narrowly acute, points not entire; base usually somewhat cordate, slightly rounded, varying from strongly cordate to little or not at all cordate; margin crenately serrate, incurved teeth glandular, individual seedlings varying in fineness and sparseness of the crenate serrations; texture thin, firm; younger leaves densely pubescent or tomentose. Stems: terete, tips of most vigorous shoots very slightly angled, at first coated with a thick hoary deciduous tomentum, later becoming olive- brown to olive- gray; lenticels oblong to linear, on older wood practically circular, usually orange- colored. Winter buds: terete, 142 rather broadly ovoid, acute; individual seedlings vary in narrowness of buds and extent to which they are appressed; buds of some seedlings slightly out- curved; color chestnut- brown; seedlings vary in amount of pubescence on buds but none are glabrous, and they are not resinous, viscid, or aromatic. The 178 sister hybrids of this series were very uniform in respect to the general characters of leaves, buds, and stems. There was, however, much difference in vigor of growth; some of them were weak and very slow- growing, as shown in FIGURE I. Brief mention has been made of these hybrids and one is illustrated in a recent report on the entire breeding project with poplars. 2 FIGURE 2. Showing large leaf of sucker branch, smaller leaf typical of old trees, and twigs of ( 1) Populus balsamifera virginiana and ( 2) P. grandidentata, and ( at 3) leaf and twig of one of the hybrids. Comparisons with parents ( see FIGUKE 2). The leaves of the hybrids resemble the leaves of P grandidentata in shape, apex, texture, color, and tomentum. The leaf base is more or less intermediate between P. grandidentata and P. balsamifera virginiana; the leaf margin resembles that of the leaves on vigorous branches of P balsamifera virginiana but is even more finely serrate. The stems resemble those of the P grandidentata in shape, color, tomentum, and appearance of the lenticels. The winter buds of the hybrids are more like those of P grandidentata in shape, pubes- 2 Stout, A. B., and Schreiner, E. J. Results of a project in hybridizing populars. Jour, of Heredity 24: 216- 229. 1933- 143 cence, and absence of the aromatic, viscid, or resinous character. The growth thus far made by the hybrids indicates that the trees will resemble the pollen parent ( P. grandidentata) in appearance. Thus in only a few of the characters is there definite influence of the seed parent; there is a decided dominance for nearly all the characters of the pollen parent. The best of these hybrids are less vigorous in growth than seedlings or plants grown from cuttings of the seed parent. Most, if not all of them, appear to be less vigorous than plants of the pollen parent. They are much less vigorous than many hybrids of other crosses in the genus Populus. None of them has merit for use in reforestation and it is doubtful if any have merit as shade trees. The writers have found no references to hybrids between the two species Populus balsamifera virginiana and P. balsamifera, either of wild origin or of experimental production. A. B. STOUT, New York Botanical Garden. E. J. SCHREINER, Oxford Paper Company. TWO IMPORTANT NEW BOOKS FOR GARDENERS L. H. Bailey and M. G. Kains— as different in style of writing as two horticulturists could hope to be— have each lately produced a new book which in its way seems quite indispensable to the gardener who wishes to know the what, how, when, and why of all that he does with his plants. Mr. Kains's volume, 1 " Modern Guide to Successful Gardening," treats each subject particularly from the point of view of methods to be used in cultivation. The first 150 pages, approximately, deal with flowers, shrubs, vines, and trees; the next 100 with fruits and vegetables, and the last, almost 100 pages, with planning and carrying out practical work in the garden. The emphasis on fruits and vegetables seems a trifle strong, especially when one considers that strawberries are given a whole chapter, while iris is merely mentioned in one line of one appendix; geraniums are not mentioned at all— unless in some other undis- 1 Kains, M. G., Modern Guide to Successful Gardening. Pp. 370, illus. Greenberg, New York. 1934. $ 2.50. 144 covered line— and peonies, asters, and delphiniums are given no greater attention. But food plants have a powerful hold on many gardeners, and the book is really amazingly complete for a volume of its size. Each one of its 49 chapters, prefaced by an amusing verse and an instructive sentence, both quoted, deals with some subject that really is of prime importance for the gardener to know. The text is clear and entertaining, and is amplified by drawings, diagrams, and tables, which are further amplified by the long appendices, listing members of some two dozen groups of plants, from roses to vegetables that will withstand frost, and giving some valuable information about each. Dr. Bailey2 takes up the culture of nearly a thousand species of plants in alphabetical order, from Abutilon to Zinnia, listing both common and scientific names for each, and treating each subject under the name most commonly used. Instructions are brief, necessarily, but adequate for the average gardener's use. Informative lists of perennials, annuals, vines, ground- covers, and such groups are offered, and fairly detailed directions are given for developing rock, water, and window gardens, for propagating, fertilizing, and pruning, and similar essential operations, all concise and practical. It is strange that neither of these new books, the one by its title a " modern" guide, and the other by virtue of its authorship presumably the latest word in horticulture, mentions one of the new California plants which are becoming increasingly popular in rock gardens and borders. The names Brodiaea, Calochortus, Lewisia, and Camassia, for example, appear in neither. South African plants are almost as seriously neglected. Ursinia ane-thoides is not mentioned; Dimorphotheca is barely cited in Dr. Bailey's book, and Felicia has won a place in neither. The list might perhaps be extended, but unnecessarily. Outside of this lack, both books have outstanding value for any gardener's use. CAROL H. WOODWARD. 2 Bailey, L. H., Gardener's Handbook. Pp. 292, illus. Macmillan, New York. 1934. $ 3.00. PUBLICATIONS OF THE NEW YORK BOTANICAL GARDEN Journal of The New York Botanical Garden, monthly, containing notes, news, and non- technical articles. Free to members of the Garden. To others, 10 cents a copy; $ 1.00 a year. Now in its thirty- fifth volume. Mycologia, bimonthly, devoted to fungi, including lichens; $ 5.00 a year. Now in its twenty- sixth volume. Official organ of the Mycological Society of America. Addisonia, semi- annual, devoted exclusively to colored plates accompanied by popular descriptions of flowering plants; eight plates in each number, thirty- two in each volume. Subscription price, $ 10.00 a volume ( two years). [ Not offered in exchange.] Now in its eighteenth volume. Bulletin of The New York Botanical Garden, containing reports of the Director- in- Chief and other official documents, and technical articles embodying results of investigations. Free to all members of the Garden; to others, $ 3.00 per volume. Now in its fourteenth volume. North American Flora. Descriptions of the wild plants of North America, including Greenland, the West Indies, and Central America. Planned to be completed in 34 volumes. Roy. 8vo. Each volume to consist of four or more parts. 73 parts now issued. Subscription price, $ 1.50 per part; a limited number of separate parts will be sold for $ 2.00 each. [ Not offered in exchange.] Memoirs of The New York Botanical Garden. Price to members of the Garden, vols. I- VI, $ 1.50 per volume; to others, $ 3.00. Vol. VII, $ 2.50 to members; to others, $ 5.00. Vol. I. An Annotated Catalogue of the Flora of Montana and the Yellowstone Park, by Per Axel Rydberg. ix + 492 pp., with map. 1900. Vol. I I . The Influence of Light and Darkness upon Growth and Development, by D. T. MacDougal. xvi + 320 pp., with 176 figures. 1903. Vol. I I I . Studies of Cretaceous Coniferous Remains from Kreischer-ville, New York, by A. Hollick and E. C. Jeffrey, xiii + 138 pp., with 29 plates. 1909. Vol. IV. Effects of the Rays of Radium on Plants, by Charles Stuart Gager. viii + 478 pp., with 73 figures and 14 plates. 1908. Vol. V. Flora of the Vicinity of New York: A Contribution to Plant Geography, by Norman Taylor, vi + 683 pp., with 9 plates. 1915. Vol. VI. Papers presented at the Celebration of the Twentieth Anniversary of The New York Botanical Garden, v i i i + 594 pp., with 43 plates and many text figures. 1916. Vol. VII. Includes New Myxophyceae from Porto Rico, by N. L. Gardner; The Flower Behavior of Avocados, by A. B. Stout; Descriptions of New Genera and Species of Plants Collected on the Mulford Biological Exploration of the Amazon Valley, 1921- 1922, by H. H. Rusby; and The Flora of the Saint Eugene Silts, Kootenay Valley, British Columbia, by Arthur Hollick. viii + 464 pp., with 47 plates, 10 charts, and II text- figures. 1927. Brittonia. A series of botanical papers. Subscription price, $ 5.00 per volume. Now in its first volume. Contributions from The New York Botanical Garden. A series of technical papers written by students or members of the staff, and reprinted from journals other than the above. Price, 25 cents each. $ 5.00 per volume. In the fourteenth volume. Flora of the Prairies and Plains of Central North America, by P. A. Rydberg. 969 pp. and 601 figures. Price, $ 5.50 postpaid. THE NEW YORK BOTANICAL GARDEN Bronx Park, New York, N. Y. G E N E R A L I N F O R M A T I ON Some of the leading features of The New York Botanical Garden are: Four hundred acres of beautifully diversified land in the northern part of the City of New York, through which flows the Bronx River. A native hemlock forest is one of the features of the tract. Plantations of thousands of native and introduced trees, shrubs, and flowering plants. Gardens, including a new rock garden, a large rose garden, a perennial border, small model gardens, and other types of plantings. Greenhouses, containing thousands of interesting plants from America and foreign countries. Flower shows throughout the year— in the spring, summer, and autumn displays of daffodils, tulips, lilacs, irises, peonies, roses, lilies, water- lilies, dahlias, and chrysanthemums; in the winter, displays of greenhouse-blooming plants. A museum, containing exhibits of fossil plants, existing plant families, local plants occurring within one hundred miles of the City of New York, and the economic uses of plants. An herbarium, comprising more than 1,700,000 specimens of American and foreign species. Exploration in different parts of the United States, the West Indies, Central and South America, for the study and collection of the characteristic flora. Scientific research in laboratories and in the field into the diversified problems of plant life. A library of botanical literature, comprising more than 43400 books and numerous pamphlets. Public lectures on a great variety of botanical topics, continuing throughout the year. Publications on botanical subjects, partly of technical, scientific, and partly of popular, interest. The education of school children and the public through the above features and the giving of free information on botanical, horticultural and forestral subjects. The Garden is dependent upon an annual appropriation by the City of New York, private benefactions, and membership fees. It possesses now nearly two thousand members, and applications for membership are always welcome. The classes of membership are: Benefactor single contribution $ 25,000 Patron single contribution 5,000 Fellow for Life single contribution 1,000 Member for Life single contribution 250 Fellowship Member annual fee 100 Sustaining Member annual fee 25 Annual Member annual fee 10 Contributions to the Garden may be deducted from taxable incomes. The following is an approved form of bequest: / hereby bequeath to The New York Botanical Garden incorporated under the Laws of New York, Chapter 285 of 1891, the sum of . Conditional bequests may be made with income payable to donor or any designated beneficiary during his or her lifetime. All requests for further information should be sent to T H E N E W YORK BOTANICAL GARDEN BRONX PARK, NEW YORK, N. Y. |
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