FT чеч А Ыз aros Annals of the Missouri Botanical Garden Volume XXVI 1939 With Twenty-eight Plates and Thirty-eight Figures Published quarterly at Fulton, Missouri, by the Board of Trustees of the Missouri Botanical Garden, St. Louis, Mo Entered as second-class matter at the post-office at Fulton, Missouri, under the Act of March 3, 1879. di e tree ‘reser a> Annals of the Missouri Botanical Garden Garden and the Graduate Laboratory of the Henry Shaw School of Botany of Washington University in A Quarterly Journal containing Scientific Contributions from the Missouri Botanical affiliation with the Missouri Botanical Garden. Information e ANNALS OF ii Missouri BOTANICAL GARDEN appears four times dur- ing the ealendar : ЖӨ е April, September, and November. Four numbers жете ы а volum Subseription Priee........ $6.00 per volume Single Numbers.......... 1.50 ea Contents of previous issues of the ANNALS OF THE MISSOURI BOTANICAL еже are listed in the Agrieultural Index, published by the H. W. Wilson Con * Except No. 3 of Vol. 22, price $5.00, and No . 2 of Vol. 25 , price $2.50. EI CAEDIS ЖЖ реке лы LM CE ае РРА TOL C О ОНЕ. 2$ b у“ " Е Е p^ wr M i h В Е Џ ki М n e | at E PS р 7 Ба А қайды г ў Bi ў я Pe wn ж 69 ee x TARAN a infos ЦРВ И қы qnm e QUA oc. Munch p occu E ipaa uo A Ra itis мазм оше ——Á—— орі €— 4 "me » ad pi" К М Адлер ЗУ y 769 L = и TN | ~ A “ ia a = O - 22) б - $ pel | = кем 3 zee [2 дон « O ae — 24 - о - on з = е Е COUR dep Ааа аға 7 TABLE OF CONTENTS A Mieroscopie Study of Coniferous Wood in Relation to Its Strength Properties..... И ЕМ ERE ra Gell Wal е Hereford Garland New or Otherwise Noteworthy Apocynaceae of Tropical America. VI..Robert E. Woodson, Jr. Studies on Variation іп Gibberella Saubi- netii (Mont.) Saec. (Fusarium grami- nearum боһмаһе)............... Mary Goddard Tree Temperatures and Thermostasy...... TT Ernest S. Reynolds New or Otherwise Noteworthy Apocynaceae of Tropical America, VIL... as eae ey URN ICTU URN Robert E. Woodson, Jr. Two New Asclepiads from the Western United States........... Robert E. Woodson, Jr. Contributions toward a Flora of Panama. III. Collections during the summer of 1938, chiefly by R. E. Woodson, Jr., P. H. Allen, IS EA Бег. as ss Ae e ак A Robert E. Woodson, Jr. and R. J. Seibert The Genetic Coefficients of Specific Differ- ence....Edgar Anderson and Ruth Peck Ownbey Morphogenetic Differences between Nico- tiana alata and N. Langsdorffii as indicated by their Response to Indoleacetie Acid... "Educ Lilian Nagel Monograph of the North American Species of the Genus Ephedra.......... Hugh C. Cutler General Index to Volume ХХУІ.................. PAGE 1- 94 95- 98 99-164 165-255 257-259 261-264 265—324 325-348 349-372 373-427 429-433 ү РРА STAFF OF THE MISSOURI BOTANICAL GARDEN Director GEORGE T. MOORE HERMANN VON SCHRENK, EDGAR ANDERSON, ist eticist Pathologi Ковект E. WOODSON, JR. JESSE M. GREE Curator of m Hin Assistant Curator of the Herbarium CARROLL W. DODGE, NELL C. HORNE Mycologist Librarian ca Editor of Publications BOARD OF TRUSTEES OF THE MISSOURI BOTANICAL GARDEN President GEORGE C. HITCHCOCK Vice-President DANIEL K. CATLIN Second Vice-President THOMAS 5. MAFFITT GEORGE T. MOORE EUGENE PETTUS WESSEL SHAPLEIGH L. Ray CARTER SAMUEL C, DAVIS DUDLEY FRENCH ETHAN А. Н. SHEPLEY EX-OFFICIO MEMBERS BERNARD Е. DICKMANN, GEORGE В. THROO Chancellor of Bo Mayor of = City of University St. Lou WILLIAM SCARLETT, J. В. MACELWANE, 8.Ј., Bishop of the Diocese of President of the кеген of Missouri Science of St. Lo K D. EAGLETON, President of the 220 of Education of St. Louis GERALD ULRICI, Secretary Annals of the Missouri Botanical Garden Vol. 26 FEBRUARY, 1939 No. 1 A MICROSCOPIC STUDY OF CONIFEROUS WOOD IN RELATION TO ITS STRENGTH PROPERTIES? HEREFORD GARLAND Research Fellow in the Henry Shaw School of Botany of Washington University? I. INTRODUCTION In a broad sense this study is motivated by a desire to add to the meager knowledge of the role played by the individual cells in the resistance of the wood to mechanical forces. More specifically, the problem is concerned with the identification of wood which is abnormally low in strength. Since it is recog- nized that woods of greater density are the stronger, an ab- normal-strength specimen is one that is weaker than the aver- age for the density range in which it occurs. Research on the strength properties of wood has been quite empirical, and the data given have represented large numbers of specimens either as average values or as average trends of relationships. Winslow (’33), in outlining the state of research in forest products, has this to say of the mechanical properties of wood: 1 An investigation carried out in the Graduate Laboratories of the Henry Shaw School of Botany and the Department of Civil Engineering of Washington Univer- sity and submitted as a thesis in partial fulfillment of the requirements for the de- gree of doetor of philosophy in the Henry Shaw Sehool of Botany of Washington University. ? A fellowship established by the Ameriean Creosoting Co. ANN. Мо. Bor. GARD., VOL. 26, 1939 (1) [Vor. 26 2 ANNALS OF THE MISSOURI BOTANICAL GARDEN The information we possess as to strength properties has been collected with only incidental reference to structure; the direction (longitudinal, radial, or tangential) in whieh the foree was applied was commonly known, and one structural characteristic, density, was always determined. The finer details of strueture were not determined, however, nor were the tests designed to show the effeet of struetural variations in any minute degree Thus there is no considerable body of literature bearing di- rectly upon the cellular variations related to strength. One type of clear coniferous wood of abnormal-strength proper- ties has been known for over forty years, but until recently its deseription has been vague. Whether this is the only type of abnormality is not known, nor is it known whether the fac- tors eausing this abnormality are also responsible for what might be called the normal variation of strength in relation to density. The purpose of this study is not the investigation of any given type of structural variation, but the investigation with the mieroscope of the differenees between strong and weak specimens of a wood of simple anatomy that have been sub- jected to simple stresses. Further, an interpretation of the mieroscopie data is attempted against a background of the literature pertaining to factors known to affect the strength of wood. IL. Review or THE Factors AFFECTING THE STRENGTH OF Woop Although the experimental part of this problem is only in- tended to constitute a step in the direction of complete control of the factors affecting strength of wood, a review of what is known of these factors is necessary for a full understanding of the problem, the methods used, and for an interpretation of the results. The discussion will be concerned with conifer- ous wood except where work on other wood applies, and the characteristics of southern pine will be emphasized. Because it is at present the only generally known type of clear coniferous wood of abnormal-strength properties, ‘‘com- pression wood’’ will be frequently referred to in this paper. The term is synonymous with the German expressions ** Rotholz'' and ‘‘Druckholz.’’ Büsgen and Münch (’29) gave a 1939 ~ i -iij ——" GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 2 good account of its causes and occurrence, and Trendelenburg (732) and Pillow and Luxford (’37) have recently reviewed its technieal properties. The literature will not be reviewed here, but it is of interest to note that Roth (795) recognized the structure in the trunks of southern pine, but seems to have been ignorant of the properties of the wood. Тһеге has been some confusion in the descriptions of **compression wood,’’ so that it would be well to quote from the summary of the most recent and the most comprehensive paper on the subject, that by Pillow and Luxford (737): Under a microscope the summerwood tracheids of compression wood appear to be nearly circular in cross section whereas those of normal wood are more or less rectangular. The fibrils of the secondary cell walls in compression wood make a higher angle in relation to the longest axis of the cells than do the The lignin content of compression wood as indicated by the species investi- gated is slightly higher and the cellulose content slightly lower than normal wood. The weight of pronounced compression wood is from 15 to 40 per cent greater than normal wood. Тһе longitudinal shrinkage of compression wood from the green to oven-dry condition varies from about 0.3 to 2.5 percent whereas normal wood has a shrinkage from about 0.1 to 0.2 percent. Тһе transverse shrinkage of compression wood is less than that of normal wood. When adjustments are made for differences in weight, compression wood is lower in M all strength properties as compared to normal wood. The ease in strength UE. Ré eis drying of the wood is Dun 80 ind for eompression wood as for normal wood. Compression wood is under eompression in the log and ipe the Mia are released, sueh as by sawing, extension of the compression wood portion occurs. There is still much to be known about this type of wood, but until a more descriptive term can be applied, it must be ге- ferred to by its accepted English designation, ‘‘compression wood." It will be used in this paper with quotation marks to avoid associating it with the compression strength properties. There may also be reference to the German terms ‘‘ Weiss- holz"' and ‘‘Zugholz’’ (tension wood) which have been applied to the wood diametrically opposite in the stem to ‘‘Rotholz.’’ DENSITY The two factors controlling density of wood are the density of wood substance (cell-wall material) and the porosity or proportion of air space to cell-wall volume. The apparent [Vor. 26 4 ANNALS OF THE MISSOURI BOTANICAL GARDEN density of wood substance seems to be one of the most invari- able features of wood. Hartig ('85) was satisfied to use the single value 1.56 for several species of conifers. Dunlap (714) found a range of 4.5 per cent in seven species including hard- woods and softwoods, but only insignificant variation between two determinations of the same species. He found 1.506 gr. per се. for longleaf pine by floating thin sections in a calibrated solution of calcium nitrate. Stamm (729) made a study of the density of wood substance and came to the conclusion that it **varies slightly among species as a result of variation in the chemical composition of the substance." He obtained densities of 1.598 for cotton cellulose, 1.594 for isolated Cross and Bevan wood cellulose (from catalpa heartwood), 1.451 for isolated lignin (insoluble in 72 per cent H2SQ., from western yellow pine heartwood), and 1.531 for loblolly pine wood substance. All these data were from the same method, water displacement at 25? C. Berkley (734), using a pyenometer method on saw- dust, found a range of 1.5156 to 1.5273 gr. per cc. embracing three species of southern pine.’ It seems evident that varia- tion in cell-wall density has little to contribute to the wide vari- ation observed in the strength of woods of the same specific gravity. Also it appears justifiable to use the specific gravity of wood as a criterion of the relative amount of wood substance in a specimen, at least in a series from the same kind of wood. The real basis, then, for the strength-specific gravity cor- relation which is known for wood is the relative amount of solid substance under the stress. The deviations from the strength- specific gravity regression must be due to some property of the solid material, either its arrangement (size, shape, and dis- tribution of the cells) or its internal structure and constitution. The great bulk of coniferous wood is made up of fibers the length of which is about 100 times the breadth. The end walls *The term ‘‘southern pine’’ refers to the hard or yellow pines native to south- eastern United States, the most common species of which are longleaf pine, Pinus palustris Mill., shortleaf pine, P. echinata Mill., and loblolly pine, P. Taeda L. These woods are not distinguishable anatomically though there are statistical dif- ferences in specific gravity and growth-ring measurements. The last two are fre- quently designated together as ‘‘commercial shortleaf pine.’’ 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 5 are tapered to points so that all but an insignificant amount of the solid material occurs as vertical tube walls. A cross-section of these tubes, then, presents an approximate map of the volumetric proportion of solid to air space, and the ratio cell-wall area -- wood-section area may be regarded as equal to the ratio specific gravity of wood — specific gravity of wood substance: em.?(sub.) em.?(sub.) gr./em.? (wood) em.?(wood) Е em.? (wood) m gr./cm.?(sub.) When a stress is applied to a eross-section of a wood speci- men (stress parallel to the fibers), it can be referred to the solid material by multiplying it by the ratio, sp. gr. substance -- sp. gr. wood: gr./em.?(sub.) kg./em.?(sub.) = kg./em.?(wood) X gr./em.? (wood) And, since sp. gr. of wood substance may be considered as соп- stant, an index of the strength of the wood substance may be had in the quotient, strength of wood — sp. gr. of wood. In studies of the strength of wood different methods of eliminating specifie gravity have been used by various workers under different designations. Botanists investigating the mechanical systems of plants (Schellenberg, '96, Sonntag, '03, Ursprung, 706) referred stress to the cell walls by making camera-lucida drawings of the cross-sections of the specimens, and measuring the areas of the walls and the lumens to obtain the ratio of substance to wood. Kollmann (736) reports the use by Monnin in 1919 of a quality index for judging wood for airplane construction : св ‘‘Statische Kennzahl, I, = —————"' 100 * r,; where с_в is the compression strength in kg./em.?, r,, is the specifie gravity of the wood at 15 per cent moisture content in [Vor. 26 6 ANNALS OF THE MISSOURI BOTANICAL GARDEN gr./em.?, and I, is the index in kilometers. Kollmann also com- pared wood with other materials in tensile strength by the factor ‘‘Reisslange’’ (breaking length), tensile strength = specific gravity. He attributed this term to von Reuleau in 1861, who evidently used it as a measure of the strength of wires and threads. It represents the length a strand can attain without breaking under its own weight in tension, all the terms being in the metric system. Rothe (’30) converted his strength data to those of strength of cell-wall substance by multiplying the compression stress by the ratio sp. gr. wood substance -- sp. gr. wood, and gave essentially the same justification given above. Trendelenburg (’31) compared European and Ameri- can Douglas fir by the quotient, strength —- sp. gr. Lassila (731) and Jalava (734) used the same fraction, calling it the ‘‘Janka quotient,’’ in comparing pine from different forest types in compression strength. Markwardt and Wilson (’35) used the same quotient to compare compression strength of a very light species and a very heavy one and called it **Spe- cific Strength.’’ In relating strength to cell-wall structure Pillow and Luxford (’37) used as the dependent variable the “тайо of strength to specific gravity," in which the specific gravity was raised to a power expressing its empirical relation- ship to the particular strength property involved. The curvi- linear strength-density correlation provided here takes the regression line through the zero-zero origin, but in the range of the concentration of data the exponents used give very nearly a straight line, so that this ratio is not incompatible with the stress-density theory given above. Berkley (734) tended toward eliminating specific gravity in his study of strength properties by choosing for analysis the specimens deviating most from the regression of strength over specific gravity. Clarke (736) employed the same method when he compared ‘‘outlying’’ specimens in the same specific gravity range. GROSS STRUCTURE It is generally known that strong wood in conifers is associ- ated with an optimum growth ring width for each kind of wood 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE T and with a high percentage of summerwood. Thus Wilson (734), speaking of the quality of wood for structural timbers, states: Seleetion for rate of growth requires the number of annual rings per inch on the end of the piece to be within a specified range. Selection for density imposes in addition to the limitations of growth the requirement of a minimum per- centage of summer wood. Structural grading rules for coniferous woods generally fol- low these principles. (a) Growth Ring Width.—This is commonly regarded as only indirectly affecting strength through specific gravity. The optimum ring width for strength appears to be the optimum for specific gravity. Thus, Markwardt and Wilson (735) il- lustrate the effect of rate of growth in conifers with a graphical correlation of specifie gravity over rate of growth, showing optima for different stand types of redwood near twenty rings рет inch. Trendelenburg (731) shows that specific gravity and strength have the same optimum ring width for Douglas fir. Paul (730) further connects growth rate with specifie gravity and with percentage of summerwood: Both very wide and very narrow annual rings in conifers usually eontain a larger proportion of the spring-wood layer, so that in these species wood repre- senting either extreme of growth may be low in specifie gravity. Alexander (735) has given for Douglas fir average fig- ures and graphical correlations of compression strength and specifie gravity over rings per inch on the same chart with superimposed ordinates. The straight-line curves for the de- pendent variables are both somewhat irregular but they have nearly the same irregularities. This seems to substantiate the assumption that specific gravity is the controlling factor here (fig. 1). The present writer has plotted Alexander’s average data as strength per unit density over rings per inch in fig. 2, the new data representing the average crushing strength di- vided by the average specific gravity for each rings-per-inch class. The result seems to indicate that only part of the relation between ring width and strength is due to specific gravity and that some other factor affecting strength varies fairly regu- [Vor. 26 8 ANNALS OF THE MISSOURI BOTANICAL GARDEN д 4000 Т : "R 3 |зорој e p.450 2-5 | UK LAS у Ый [7] же д» ОЛ БЕРУ Б Ө БР АМА 5 [20bo| 4. 40 -à-* | | SHECHFI ITY E = | о | 10po} = | RÍN Пс | Е 0 5 10 15 20 25 30 35 COMPRESSION PARALLEL ТО THE GRAIN Fig. erage compression strength parallel to the grain and average specifie gravity Займ over rings per ineh for green Douglas fir. (After Alexander, 735.) larly with growth rate. Since the original material was chosen to be truly representative of **every varying condition of struc- ture from pith to bark and from stump to top," the low strength on the rapid-growth end of the curve is probably partly due to the presence of wide-ringed material such as '*eompression wood"! and wood near the pith, which are known to be abnormal in strength properties. Koehler (738) indicates that wide-ringed loblolly pine ranks low in most strength properties for its specific gravity and has certain resemblances to ‘‘compression wood." Не shows graphically the high frequency of wood of high longitudinal | ты Д 1 |_ d | ТІНІН ‹ ГЕН 4 2 ( ‹ 91116 IBEREREL INNER ole V IN вание вии ol" 1 ӨТТ + - =“ 4 > | Lid ERASER ia ЕНІН fd BNEREWZAN a d Li | Е + LH е ‘+ | 50 7 44 | Г] ы | меж, 4 5 1 2 ПИТ н | | БЕЛ H | T | mim | [s | ВЕРЕН аш 4 LH 1 1 аннат т. HH HH HHH | 4 ЕР LH КЕЕН ТІГІ ЕП i = Ws i H H i | 1 ELS | | | didis | р ы a A a | | | ГЕРЕ НИ ре ж ИЕ EI КЕЕН duni 22222 500212 9 | Н-555 ВРЕТ | LLLELLELLLLIILI ПЕНЕН 4 Н ЕГЕН. ‘i уп ве Бе BB м , ГрГУ? | 71 БГ EA LII 3 ешш зета LI | || ташы тө LII || LII о 5 10 15 20 25 50 35 RINGS PER INCH Fig. 2. Strength- -density index (average compressive strength in lbs./in. + average specific gravity іп gr./ec.) plotted over rings per inch for the data of fig. 1. 193 GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 9 shrinkage among wider-ringed specimens of loblolly and slash pine. This feature is typical of ‘‘compression wood." (b) Percentage of Summerwood.—The visual estimation of density of coniferous wood is based on the fact that summer- wood is more dense than springwood. Percentage of summer- wood is a good criterion of specific gravity only in so far as its density is constant. Grading rules control this factor only in specifying that the color of the summerwood be dark. It is certain that there are variations in density of summerwood within any species and that the relative areas of springwood and summerwood cannot be used as true eriteria of mechanical properties unless they are qualified by specifie gravity. With wood density and percentage of summerwood constant, the distribution of solid wood substance between springwood and summerwood may vary. 'This would reflect variations in fiber measurements (cell diameter and wall thickness) which per- haps affect the strength properties of the individual cells. At least, we can conceive that two tubes of the same material, length, and cross-sectional wall area, but with different di- ameters and wall thicknesses, would react differently in end compression. Clarke (’33) made a correlation study of strength, specific gravity, ring width, and percentage of sum- merwood in ash. Since with specific gravity constant, strength decreased with an increase of summerwood, he concluded that the thickness of the walls of the summerwood fibers is an im- portant controlling factor. The empirical nature of the previous research on the me- chanical properties of wood is attested by the dearth of litera- ture on the strength of isolated springwood and summerwood. In the first part of the century botanists considered this aspect, but they worked with what is regarded as abnormal wood and the methods of testing were not well controlled. Sonntag (’03) reported on the tensile strength of spruce specimens of 1 mm.- square section in ‘‘Rothholz’’ (‘‘compression wood’’) and ‘“Weissholz’’ (white wood, wood diametrically opposite ‘‘com- pression wood’’ in the stem). Although his tests were few and widely varying, summerwood was found to be stronger than [Vor. 26 10 ANNALS OF THE MISSOURI BOTANICAL GARDEN springwood in tension parallel to the fibers in both types of wood, even basing the stress on cell-wall area. Ursprung (706) reported the same relation for springwood and summerwood of the upper and lower sides of branches of spruce in both ten- sile and compressive strength. Von Schrenk (728), testing small beams of southern pine, found that springwood had roughly half the maximum fiber stress of summerwood. For- saith (733) used small beams (2" x .09" x .09"), each with a single layer of springwood and one of summerwood. He re- ported bending strength and stiffness when these layers were in different positions (springwood up, springwood down, and springwood at side.) Не concluded that summerwood is stronger in compression than springwood is in tension, and that ‘‘the difference between the ultimate strength in ten- sion and compression is greater in springwood than in sum- merwood,’’ also, that ‘‘stiffness is more or less controlled by the summerwood.”’’ It may be concluded that there is a need for a study of growth rate and strength-density which carries the controls down to measurements of cell diameters and cell-wall thicknesses in springwood and summerwood of carefully chosen normal wood. (c) Heartwood and Sapwood.—In the wide testing experi- enee of the Forest Produets Laboratory (Markwardt and Wil- son, 7395) “по effect on the mechanical properties of most species due to change from sapwood to heartwood has been found." The structural features do not change іп the process, but the heartwood is infiltrated with added materials which may be dissolved out with apparently no effect upon the wood substance. Luxford's (731) tests on species high in heartwood extraetives indicate that heartwood has some strength ad- vantage, especially in compressive strength parallel to the grain. Where specific gravity is to be rigidly controlled it should be remembered that'extraectives add to the weight of heartwood, and this may be considerable in resinous species. Berkley ('34) was able to improve his relationships of strength over specific 1939] | GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 11 gravity for southern pine by correcting specifie gravity for benzol extractive. HISTOLOGY Differences in the kinds of cells, their proportions and their arrangements, may be expected to explain partially differences in strength properties among woods of different anatomical types. Likewise, variations in amounts of different cellular elements might cause variations in the strength-density rela- tionship of a group of specimens of the same anatomy. In elucidating the causes for brashness in wood Koehler (’33) gave deficiency of wood fibers! (oak) as one of the reasons for deviations in the relation of per cent of summerwood to tough- ness. In this case there would be an excess of wood paren- ehyma, a cell type that differs from the wood fiber not only in the relation of wall thickness to cell diameter but also in morphology. Coniferous woods are simple in that the vertical elements are of only two general kinds, parenchyma cells and tracheids, and the latter predominate. In the pines, wood parenchyma is nor- mally confined to one or two layers of thin-walled flattened cells surrounding resin canals. Vertical resin canals are inter- cellular spaces without walls, and so do not affect the strength of wood substance except as they account for the presence of parenchyma. Their effect on the strength of wood is limited to an interruption of the solidity of the tracheid mass. Berkley (’34) found the diameter of resin ducts in southern pine vary- ing from 0.19 mm. to 0.25 mm. The cross-sectional area was 0.66-2.5 per cent, and the variation between strong and weak specimens was evidently not significant. Wood rays certainly must play an important role in the distribution of stresses in wood, but there is little definitely known about this. They exclude part of the weight of the wood from participating in efficient axial stress resistance and they cause deformation of the contours of adjacent tracheids. On the other hand, they form a very effective lateral bracing and * The term ** wood fiber’’ refers to a particular type of cell found in hardwoods. The term **fiber"? when used alone refers to fibrous cells in general. [Vor. 26 12 ANNALS OF THE MISSOURI BOTANICAL GARDEN seem to make up for the weaknesses that might be due to a lamellar (springwood and summerwood) structure. In end compression tests, wood fraetures quite regularly in a sloping radial plane. Berkley ('34) attributed this directly to the rays and reported that Thil in 1900 and Fulton in 1912 agreed with him. Jaccard (710), Robinson (720), Forsaith (733), and Bien- fait (726) each observed that initial failure is not associated with the rays. Iwanoff (733) found that the fibers bend most frequently at the rays, but that there is another more angular type of fiber failure that is not dependent upon the rays. Bien- fait (726) saw no difference between radial and tangential walls as to indications of initial compression failure. He suggested that the plane of fracture is indirectly caused by the stiffening effect of the wood rays against gross fracture in a tangential plane. Koehler (733) regards the rays as ineffective in deter- mining resistance to toughness. Among Berkley's (734) out- lying specimens of southern pine, in the graphical correlation of compressive strength with specific gravity, the weaker speci- mens averaged about one per cent more of total area occupied by resin duets and wood rays than the stronger specimens. He concluded that the larger number of wood rays and resin canals contributed to the weakness of the material, especially the wide-ringed, short-fibered wood in the first few rings near the pith. Fusiform rays (containing horizontal resin canals), also measured by Berkley, varied from 0.053 to 0.075 mm. in width and from 0.35 per cent to 1.61 per cent of total area. He re- garded them as effective in causing compression failures. It seems reasonable that the rays may play two opposing roles in the resistance to stress in wood, which may be partially compensating. TRACHEID MORPHOLOGY Forsaith (’26) stated that tracheids occupy 90 per cent of the stelar volume in conifers. Berkley (’34) showed that resin ducts and rays occupy roughly 10 per cent of the cross-sectional area in southern pine. Since the ray and parenchyma cells have much thinner walls than tracheids, it is certain that tracheids 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 13 constitute well over 90 per cent of the weight of this type of wood. It would seem that an explanation of the large strength- density variations must be associated with this element. Тһе tracheid is defined as an ‘‘imperforate cell with pits to congenerie elements bordered" (Record et al., 733). In south- ern pine its length is about 100 times its greatest breadth. It varies in cross-section from approximately isodiametric, large- lumened, thin-walled in springwood, to tangentially flattened, small-lumened, thick-walled in summerwood. Normally these cells fit closely together in well-defined radial rows. The cells of **eompression wood’’ are more or less rounded in cross- section, have larger lumens in summerwood and thicker walls in springwood than normal wood, are less regular in arrange- ment, and may have intercellular spaces among them at the eorners. Тһе walls of normal tracheids are parallel except near the ends where they taper to a point in summerwood or to a radially oriented wedge in springwood. Тһе ends may be more or less curved radially. Abnormal cells may have irregu- lar eurvature throughout the length, which, according to Berk- ley (734), is associated with specimens weak in end compres- sion. The length of tracheids varies considerably among speci- mens of the same wood. Short tracheids are known to be as- sociated with ‘‘compression wood’’ and the wide-ringed ma- terial of the first several years’ growth. Berkley (734) found the average length of tracheids in his southern pine specimens to be between about 2.5 mm. and 5.0 mm. However, the aver- age length of tracheids for his strongest and weakest woods was about the same. Koehler (733) saw no relation between tracheid length and toughness and attributed this to the fact that the fibers are cemented firmly together and a slipping be- tween fibers is not involved in failure. Sonntag (703) found considerable difference in the range of tracheid length between ‘‘compression wood" and ‘‘tension wood’’ but did not at- tribute the low tensile strength of ‘‘compression wood" to this. Since stresses parallel to the fibers actually cause failure in diagonal shear and since the contour of the fiber is not uni- [Vor. 26 14 ANNALS OF THE MISSOURI BOTANICAL GARDEN form throughout its length, it is probable that the above con- clusions are valid in spite of the fact that some types of weak wood have short fibers. Bordered pits are confined to the radial walls of tracheids almost exclusively. А bordered pit is defined as ‘‘typically, a pit in which the cavity becomes abruptly constricted during the thickening of the secondary wall’’ (Record ей al., ’33). View- ing an isolated tracheid the bordered pit appears as a saucer- shaped depression on the wall with a small circular opening at its center, the canal. The pits of contiguous tracheids are paired so that the depressions form a lenticular space, the chamber. In springwood the whole wall takes the form of the chamber and has about the same thickness throughout except for a rounding off at the canal. In springwood of southern pines the chamber (marking the border) extends to half or more the width of the cell. In summerwood the border and canal are smaller, the chamber is shallower in the wall surface, and the canal extends from the outer aperture (at the chamber) to the inner aperture at the inner wall surface. Usually the inner aperture is more or less lens- or slit-shaped. Bordered pits are much less numerous in summerwood than in spring- wood. Jaccard (710) and Tiemann (706) regarded the bordered pits as points of weakness in compression, but Robinson (’20), Bienfait (’26), and Forsaith (’33) did not agree. Forsaith ob- served that both compression and tension failures avoid the pits and that the line of fracture runs around the border rather than through the canal. Koehler (733) regarded bordered pits as stronger than other parts of the wall because of concentric fibrillar arrangement in the overhanging wall. Sonntag (703) found larger bordered pits and especially longer pit slits in *eompression ооа?! than in ‘‘tension ооа”! of spruce branches and assigned this as a cause for lower tensile strength of ‘‘compression wood."' Each conifer tracheid comes in contact with a wood ray at a number of places in its length. At these crossings the tracheid wall is indented or the whole cell is bent to conform 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 15 to the lenticular cross-section of the rays. This bending of the fiber wall has been blamed for a lower resistance of the wood to axial compression stress. In the ray crossings the pits to the ray parenchyma cells have large canals, and the reduc- tion in wall section may be considerable. Forsaith (733) ob- served that the line of fracture (tension?) may shift slightly to take advantage of these pits. It has been shown that there are several features of the archi- tecture of the individual tracheid the variation of which may have an effect on the strength of wood as a whole. The study of the parts played by these features is complicated by the fact that the fibers are cemented together with a material which seems to hinder the fibers from acting individually. Thus from his microscopic examination of fractures in small bending specimens, Forsaith (733) concluded that: ... the plane of fracture follows the area of maximum stress, and that anatomical inequalities in wood do not deflect the line of cleavage more than a few microns. Furthermore, where fracture does jump from cell to cell, there seems to be no specific reason why it should depart from the middle lamella line at this point. All things considered, it would appear that the minute struc- ture of the wood plays a relatively unimportant part in locating failure, in comparison with that determined by a concentration of stresses in the region of maximum moment. This may be valid for bending fraetures because here the longitudinal stresses are concentrated under the loading point. And especially is it true for Forsaith's tests where one kind of stress was confined to one part of the annual ring and there was not the complication of stresses as in the whole wood where two different kinds of material are involved. The axial compression test, too, seems to be ill adapted to the study of centers of weakness in the cell structure. Once failure takes place in a relatively small group of cells, or theo- retically at a certain point on the wall of a single cell, the frac- ture seems to affect the neighboring cells and the progress of the effect often proceeds in a quite regular pattern without much selection of points of weakness. In axial tension fracture, however, there is little regularity, and it seems valid to assume that the pattern of fracture is determined by the points of [Vor. 26 16 ANNALS OF THE MISSOURI BOTANICAL GARDEN weakness in the individual fibers which may be associated with eontour features. TRACHEID WALL STRUCTURE With ordinary mieroseopie methods fiber walls of light- colored woods (and sapwood) usually appear quite transpar- ent and without structure. With staining, a thin outer layer may be differentiated, and under certain conditions striations and checks may be seen in longitudinal view which indicate a spiral structure. Polarized light confirms the concentric and helical anisotropy. Chemical or mechanical micro-dissection may serve to separate fine threads or fibrils from the wall. These facts have been known for nearly a century, but only recently have details been provided for even the structure of the cell wall within the range of the microscope. Below microscopic range an hypothetical crystal-like unit suggested by Nageli in the middle of the last century, and named by him the ‘‘micelle,’’ has been widely accepted. Since then the con- cept has been carried over into the field of colloidal chemistry where the unit is often designated as one type of crystallite. Although great advancement has been made in the understand- ing of the sub-fibrillar structure of the plant cell wall since Nageli’s time, the micelle is still without exact definition. The recent work by I. W. Bailey and his associates on the cambium and its derivative tissues has yielded the most lucid exposition yet available of the visible structure of the conifer tracheid. Kerr and Bailey ('34) gave the results of their opti- eal and chemical differentiation of the lamellae of normal woody fibers and offered a terminology to clear up obvious dis- crepancies in designation by earlier workers. This terminol- ogy is used in the present paper. In order from the outermost layer the terms are: middle lamella (or intercellular sub- stance), cambial (or primary) wall, and secondary wall with its outer, central and inner layers. Between contiguous mature fibers is a single layer of opti- cally anisotropic material known as the middle lamella. It is quite thin except between the rounded corners of the tracheids, 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 17 and is difficult to distinguish from the true primary wall layers of the two adjacent cells because all three are highly lignified. It has been shown to contain, besides lignin, substances which are dissolved by solvents for polyuronides. The outermost true layer of the cell wall is designated the primary or cambial wall. This is the original wall of the cam- bial initial, and though very thin and highly lignified it has been shown to have retained a true cellulose structure and also some of the original polyuronides of the cambial initial. The cellu- lose in the primary wall is shown to have positive birefrin- gence in both transverse and longitudinal sections. Bailey (738) has observed a wide variety of structural patterns which are all porous but coherent. His figure suggests the ‘‘folien- struktur" of Frey-Wyssling (735), who attributed it to all primary meristems. In this structure the cellulose is layered in the plane of the cell wall but is not oriented in a direction perpendicular to this plane. Because of its thinness and lack of orientation the primary wall may act mechanically with the true middle lamella as an amorphous substance, the binder be- tween the cells. Next within the primary wall lies the secondary wall. By its optical activity it is seen to consist largely of well-oriented cellulose, though it is usually more or less lignified (Bailey and Kerr, 735, ’37), with the lignin constituent variously dis- tributed. Normally in tracheids the secondary wall is divided into three consecutive layers according to the fibrillar orienta- tions: (1) a thin layer (next to the primary wall) with the fibrillar orientation in a relatively flat helix (45° to almost 90° with the cell axis); (2) a thick central layer with fibrils in a relatively steep helix (almost 0° to 45° with the cell axis) ; and (3) a very thin inner layer with fibrils in a more or less flat helix. The inner layer is least well known though its ani- sotropy has been shown by birefringence in both longitudinal and transverse sections of the wall. The fibrillar structure of the central layer may often be de- tected with ordinary microscopic methods. It is evident from striations and checks in the wall and from the threads or fibrils [Vor. 26 18 ANNALS OF THE MISSOURI BOTANICAL GARDEN of cellulose which сап be dissected mechanically (Seifriz and Hock, 736, and others) and chemically (Ritter, '35, and others). The outer layer may also be seen to be made up of thread-like fibrils if it is viewed apart from the central layer. Although Ritter (735) has shown fibrils to occur as threads as long as 230 и, Bailey and Kerr (735) maintain that the cellulose of the central layer oceurs in a continuous system of heterogeneous elongated and anastomosing ‘‘complexes.’’ They state: The form and size of the fragments whieh may be disseeted from the secondary wall are clearly dependent upon the structural pattern of the matrix of cellu- lose and upon the type and severity of the chemical and mechanical treatments to which the material is subjected. It is feasible to agree with them that the wide variety of proposed ‘‘ultimate units’’ of cellulose may be due to differ- ences in chemical technique. Their concept of the fibrillar structure includes the interweaving of an anastomosing system of non-cellulosic materials within the interstices of the cellu- lose structure, and they have shown photographic evidence of similar patterns obtained by treatment with lignin solvents and with cellulose solvents. These chemical patterns will be discussed in the next section. Bailey and Vestal (’37), with a method of forming iodine crystal aggregates within the interstices of the cellulose struc- ture, have presented convincing evidence of the structural orientation in the outer and central layers of normal conifer tracheids. Their survey indicates that the angles of orientation are not specific for species of wood. They regard as the normal condition in summerwood an axial orientation of the central layer and a helical one for the outer layer; in springwood the central layer is helical and the outer layer is perpendicular to the axis. These patterns were not found to be strictly confined to each part of the annual ring. The angles of orientation may vary from cell to cell, so that combinations of axial central wall with transverse outer wall and helical central wall with helical outer wall were of common occurrence. Regarding changes in orientation within the central layer, Bailey and Vestal (’37) state: 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 19 The orientation of the fibrils may fluctuate, at times, in the successively formed growth rings"! or lamellae of the central layer, but pronounced shifts are of relatively infrequent occurrence in the tracheids of conifers. Regularly recurring changes from right-handed to left-handed helixes or vice-versa, such as are hypothesized by various investigators, are rarely, if ever, encountered in the central layer of coniferous tracheids. Scarth, Gibbs, and Spier (’29), Liidtke (’31), and others have described the secondary wall of fibers as made up of as many as ten or more concentric laminae, the direction of the slope of the fibril axis alternating with each layer, and with these laminae constituting separate cellulose structural systems separated by layers of amorphous material. Ritter and Chi- dester (’28) gave photographs of elm fibers in which the sleeve-like lamellae have been made to telescope by chemical treatment, and they attributed this structure to wood fibers in general. Bailey and Kerr (’35) ascribed it to only certain types of cells. They concluded, after a wide survey of gymno- sperms and angiosperms, that the secondary wall of normal tracheids, fiber-tracheids, and libriform fibers consists of but three layers of varying orientations (as indicated above), and further that the central layer consists of a continuous struc- tural system (the cellulose matrix with an interwoven non- cellulosic structure). The iodine-crystal technique of Bailey and Vestal (’37) has given detail in fibrillar deviations within a given wall layer. The linear fibrillar structure of the outer layer seems to be discontinuous at the border (chamber) of the bordered pits, and within the border the fibrils are in concentric orienta- tion. The fibrils of the central layer, however, seem merely to be deviated around the pit canal from their normal course. This deflection is given by Bailey and Vestal as a reason for the radial walls in springwood having a greater fibrillar angle than the tangential walls. Since the central layer normally makes up the greater part of the tracheid wall, its properties are ordinarily designated as those of the entire cell wall. Preston (’34), in a quantitative study of the organization of [This is the chemical pattern which will be discussed below. [Vor. 26 20 ANNALS OF THE MISSOURI BOTANICAL GARDEN the conifer tracheid cell wall, noted that the fibrillar inclina- tion is greater on radial walls than on tangential walls and that the angle on the radial wall varies between growth rings as a funetion of average length of springwood tracheid in the ring and of average radial breadth. Maby (736), using wall checks and pit slits (elongated inner orifices of bordered pits common in summerwood) as indications of structural orientation in tracheids, found for Tsuga heterophylla sum- merwood good positive correlation between angle of inclina- tion with the fiber axis and radial lumen width. Wall thickness did not have good correlation with the angle. This worker also observed that in hemlock springwood fibrillar orientation of the radial wall at the pits is not a good criterion of the orienta- tion in the clear, the average angle for pit slits being about twice that of the checks in the clear. Further, he observed that the orientation at ray crossings was little more than half the angle in the clear. It appears that orientation in springwood tracheids is quite variable and that a true average would em- brace several widely different morphological conditions. That orientation of the fibrillar structure is important in de- termining strength of fibers is not difficult to conceive; especi- ally is this true in consideration of tensile stresses. It is known, for instance, that the very strong bast fibers of ramie and flax have good fibrillar orientation; that is, the fibrils are almost parallel to the fiber axis. That the cellulose fibrils of wood (matrix of elongated com- plexes) are more resistant mechanically than the non-cellulose constituents (interwoven system of isotropic material) may be supported by а brief discussion of the sub-mieroscopic struc- ture of wood substance. X-ray, polarized light, and swelling technique have demonstrated that the cellulose is oriented parallel to the fibril axis. X-ray diffraction analysis has further shown that the cellulose molecule consists of long chains of anhydroglucose units. The length of the chains and their combinations into structures up to the limits of miero- scopic visibility have not yet been agreed upon. Meyer (728) thinks that the chains are about 60 glucose units long, very гм, Се * 2 $ 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 21 strong by reason of primary valence bonds between the glucose units, and that they are held together in bundles (micellae) by secondary valenees the high force of which he attributes to the size of the large chain-like molecule. Further, the unsatisfied secondary valences of the outer chains of the micellae consti- tute a Ғогсе by which the micelle may adhere to other micellae or may adsorb other molecules. Astbury (733) and others view the micelle not as a unit structure but merely as a concentration of molecular chains of varying lengths some of which may ex- tend to other micellae forming a continuous cellulose system of indefinite pattern. This concept seems well supported by several different types of physical measurement (Stamm, '36) which give molecular chain lengths far exceeding the unit micellae that have been hypothesized. Below the size of the fibril the problem of the strength of wood is in a theoretical field, but the rapidly developing study of colloidal chemistry may be expected soon to yield methods of obtaining significant submicroscopic data. It must be borne in mind that even if all the factors in microscopic range were controlled there might exist within the fibril structural variables of importance to strength. The non-cellulosic constituents of wood are amor- phous, i.e., have no organized molecular forces, and as such must be regarded as secondary in determining strength prop- erties High fibrillar angle occurs with low strength in both com- pression and tension in ‘‘compression wood." Pillow and Luxford (787) have plotted three different strength-density ratios over the sine of the average angle of slope of fibrils for eight specimens of ‘‘compression wood’’ and six specimens of normal wood of air-dry loblolly pine. The average angles were weighted on the basis of springw ood-summerwood pro- portions. The normal wood specimens ‘fell between 14° and 16°, while those of ‘‘compression wood’’ had a range of about 26? to 849, In spite of the small amount of data and the wide gap in slope of fibrils between normal wood and **compression wood,’’ there appear to be good graphical relationships. Maxi- mum crushing strength and modulus of elasticity in bending [Vor. 26 22 ANNALS OF THE MISSOURI BOTANICAL GARDEN vary almost linearly through ‘‘compression wood" to nor- mal wood. Modulus of rupture! seems to vary linearly in the **eompression wood’’ region, but the specimens with average angle of 26? appear to be almost as strong as normal wood. This would indicate that ultimate bending strength is not af- fected until the average fibrillar angle reaches about 25° where it drops off rapidly with inereasing angle. Of the three strength properties shown here, modulus of elasticity in bend- ing, on a density basis, is the most sensitive to changes in fibril- lar angle and appears to have the least dispersion from the regression line. The bending-strength relationship is the most inexplicable and is also the most unsatisfactory statistically. The value of using angle of fibrillar orientation for prediet- ing strength may be roughly conceived by comparing the dis- persion in the graphical correlation deseribed above, where strength is made dependent upon both specifie gravity and fibril angle, with one in which only specifie gravity is used as а criterion. The above relationship for compression strength has a dispersion range of about 2000 lbs. / in.? per (gr./eo.)1-25, which is equivalent to about 1000 Ibs. / in.? for the average spe- cifie gravities given in the tables for air-dry loblolly pine speci- mens. This may be compared with a dispersion range of about 3500 Ibs. / in.? as shown in Berkley's ('34) plot of compressive strength over specifie gravity for air-dry loblolly pine. Even from this crude comparison and the few data upon which it is based, the fibrillar orientation angle in the central layer of secondary walls of the conifer tracheid gives promise as a quantitative eriterion of strength properties of the wood in axial stresses. It is interesting to note that fibril angle is important in axial compressive strength, in the light of microscopic evidence that cell wall fracture in compression seems to be independent of fibrillar strueture. Many workers, notably Robinson ('20) and Bienfait (726), have reported the so-called ‘‘slip lines’’ ос- eurring in the walls (seen in longitudinal section) of wood fibers that have been subjected to longitudinal compressive * This is a measure of bending strength. 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 23 stresses. Тһеве lines represent radially sloping tangential planes of shear much as might be expected in tubes of isotropic material which have been subjected to end compression. The angle in a radial plane which these lines make with the cell axis is about 70° according to Bienfait (76) and Iwanoff (738). These shear planes extend transversely or at a slight incline around the cell in the wall. They oceur concentrated in the re- gion of gross compression failure, and are more widely dis- tributed in green wood that has been stressed than in dry. Robinson (720) found them in specimens stressed just to the elastic limit and called them indications of initial failure. Koehler (733) suggests that they are sometimes induced by stresses in the tree and gives their occurrence as one of the eauses for brash tension failure. Robinson (720) observed that longitudinal tension failure of the fiber wall occurs in planes parallel to the pit slits in the summerwood of normal spruce, but for **brittle" spruce and for a number of harder woods, including pitch pine, the wall fracture is transverse, resembling the compression fracture. Koehler (733) has shown tension fractures in cells at least partially following the fibrillar orientation, indicating planes of weakness between the fibrils. He concludes that there is a relation between fibril angle and tensile strength, thus: Obviously the fibrils must also break somewhere, as well as separate from each other, in order for a fracture to be eomplete, but the greater the slope of the fibrils the smaller will be the failure within them and the greater the failure between them. If the fibrils should make an angle of nearly 909 with the cell axis, a condition approached in some hardwood vessels, then failure in ten- sion along the grain would be almost entirely between fibrils and the resistance offered by the cell wall would be relatively small. With regard to regenerated cellulose products, Houwink (37) suggests that strength may be proportional to micelle length for well-oriented material and supports this by showing that high viscosity of the solution produces strong rayon. Viscosity is thought to be dependent upon micelle length. Не illustrates fracture planes for long and short micellae pro- gressing between the micellae and transverse to their orienta- tion. The longer micellae force the fracture line into a more [Vor. 26 24 ANNALS OF THE MISSOURI BOTANICAL GARDEN deviating and longer path than do the short ones, thus provid- ing more area for the distribution of a given stress. This con- cept may be applied to the anastomosing continuous system of fibrils in natural fibers, by taking as fibril length the longitudi- nal distance between successive thin places (points of weak- ness) in the framework. Chemical dissection of fibrils indicates that some points in the framework are less resistant to sol- vents than others, and there is a possibility that a quantitative structural measurement may be attained through controlled chemical dissection. The transversely oriented outer layer of fibers has generally been neglected in structural considerations. However, Sonntag (709) suggested that the difference in the fibril angle between outer and inner (central) wall is important in the mechanism of failure under axial tension. He used as a model two wire hel- ices, one with a flat spiral and one with a steep spiral, the latter inside the former and attached firmly to it at the ends. If this system is stretched longitudinally the inner helix is reduced in diameter more than the outer one and thus pulls away from it. This mechanism was offered as the cause of concentric dis- continuities in the cell structure that lead to ultimate fracture of the wood. Thus ‘‘compression wood’’ would be less likely to fail between the outer layer and the central layer than nor- mal wood, because the angle of spiral is more nearly the same in the two layers. However, other structural abnormalities must offset the advantages since ‘‘compression wood" is no- toriously weak in tension. The continuous micellar structure of the central layer of the tracheid as elaborated above referred to normal tracheids. Bailey and Kerr ('35) state: Conspicuous discontinuities are, however, of not infrequent occurrence in the peculiar tracheids of ‘‘compression wood,’’ in so-called gelatinous fibers, in certain types of bast fibers, and in sclerids. This is due to narrow layers of truly isotropic material which contain little if any cellulose. Radio-helical discontinuities or ‘‘checks’’ in the fiber wall are conspicuous and well known in ‘‘compression wood.” Hartig (701) illustrated this type of tracheid in some detail. In cross- 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 25 section the checks open into the lumen and extend nearly aeross the centrallayer. They may branch dichotomously for a short distance near the outer layer. Тһе checks follow the helical orientations of the fibrils, forming radio-helical plates. Hartig also illustrated ‘‘tension wood’’ and showed radial checks which are less profuse and extended from the outer border of the central layer a short way into it. Such checks were not found in fresh wood and were attributed to drying. Another anomalous feature shown for ‘‘tension wood"! is the occur- rence of spiral thickenings on the inner face of the secondary wall (tertiary wall), especially іп summerwood (spruce). Hartig also mentioned an extraordinary development of the tertiary wall (inner layer of the secondary wall). He believed this layer to be absent in ‘‘compression wood.”’ CHEMISTRY A logical method of attack on the strength problems of any structure would entail an examination of the mechanical prop- erties of the various component materials. Unfortunately the materials which compose wood are so intimately associated and apparently so heterogeneous that only general and vague con- tributions to their individual study can be expected from chem- ical considerations at present. The constituents of wood are usually grouped in three classes: (1) cellulose, (2) hemicellu- loses, (3) lignin. Quantitative determination depends upon solvents used, their concentration, and exact conditions of procedure. Cellulose is a long-chain polymer whose molecular unit is known but whose chain length is probably variable. Hemicel- luloses constitute a mixture of carbohydrates some of which are associated with cellulose in the structural framework and some are not (Norman, '37). Lignin is а non-carbohydrate of unknown chemical structure, and amorphous. Koehler (733) is of the opinion that the chemical composition of wood is relatively invariable within a species. Ritter and Fleck (’26) found that for a number of species springwood is mostly lower in cellulose and higher in lignin than summerwood. This is explained by the fact that lignin tends to be concentrated in the [Vor. 26 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN **middle lamella’’ and that the ‘‘middle lamella’’ is a greater proportion of the total wall volume in the thin-walled spring- wood than in the summerwood. Dadswell and Hawley (’29) reported the difference in chemical composition between brash and tough specimens and between normal wood and ‘‘com- pression wood.’’ Brash Douglas fir of the same density as tough wood had insignificantly greater percentage of cellulose and of lignin than normal. The measure of toughness was 276 em.-kg. for the tough specimens and 132 em.-kg. for the brash ones. Although the authors did not observe structural dif- ferences in the above specimens they believed that ‘‘there may be structural differences that fully account for the strength dif- ferences." Comparing normal wood and ‘‘compression wood’? of Sitka spruce and redwood, they found appreciably lower cellulose content and higher lignin content in ‘‘compression wood.’’ Here structural differences were known, but they were “тоб certain that they were the cause of the variations in strength properties." They also found that the springwood- summerwood relationship of the cellulose and lignin content as shown by Ritter and Fleck was reversed in the case of red- wood **eompression wood.’’ These authors (Dadswell and Hawley, '29) are not willing to agree with the concept that has been general among bota- nists, that lignification is always a source of strength in cellu- lose plant fiber, nor do they agree with Schorger whom they quote, ‘‘It is known that the amount of lignin present in a wood has no direct relation to its mechanical properties." They point out that lignin occurs in a ‘‘free condition ’”’ in the middle lamella and mixed with relatively large amounts of other ma- terial within the fiber, and offer this pertinent observation: Variations in the amount of lignin, therefore, have entirely different effects on the strength, depending upon where the variation occurs. Increased lignin content in those parts of the structure where it is mixed with cellulose may inerease certain strength properties, while inereased lignin content due to inereased size of the middle lamella may decrease certain strength properties. This concept leads us back to the more recent work of Bailey and Kerr (735, 737). They have disclosed by the use of ap- 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 27 propriate solvents on very thin wood sections what might be called the chemical pattern of cellulosic and non-cellulosic con- stituents of the central layer of the secondary wall. The pat- terns are explained thus: Lamellae of varying porosity or density are due to fluctuations particularly in the number of fibrils per unit area. In other words, the fibrils are loosely aggregated in the more porous lamellae and are closely compacted in the denser lamellae. [Bailey and Kerr, 737] Ina survey of the fibrous cells of higher plants there was shown to be a wide variety of patterns made up of concentric and radial lamellae or zones of various spacing and promi . In their later paper Bailey and Kerr (737) have elucidated the distribution patterns in the conifer tracheid which vary from the normal condition to that of ‘‘compression wood"' as ex- tremes and show intergrading forms. In the broad central layer of the secondary wall of normal tracheids the laminae of varying density are relatively narrow and arranged concentri- eally, though a weak radial pattern of density may be seen as an undertone. There are no discontinuities in the cellulose sys- tem. In the intermediate forms the radial pattern gains promi- пепсе, and there may appear to be superimposed concentric and radial distribution. “Тһе wall may exhibit a prevailingly and finely radial pattern.’’ The fibrillar system may still be continuous though ‘‘it tends to develop radio-longitudinal cracks in drying. . . ."' In the extreme case of ‘‘compression wood’’ the broad inner layer is ‘‘composed of coarse, radio- helically oriented plates’’ which are separated by actual dis- continuities in the cellulose system. ‘‘Furthermore, the broad inner layer is separated from the narrow first-formed layer of the secondary wall by an isotropic layer of non-cellulosic com- position.’’ This last type of wall has no detectable inner wall comparable to that of normal tracheids (Bailey, 738). Although the chemistry of the cell wall is too obscure for an exact structural analysis, the above information on the dis- tribution of the two main classes of materials, combined with a knowledge of the longitudinal orientation of the wall, should lead to an understanding of the processes of strength resist- [Vor. 26 28 ANNALS OF THE MISSOURI BOTANICAL GARDEN ance in the cell. This follows on the assumption that cellulose is rigid and the non-cellulosie material furnishes planes or re- gions of weakness. Regarding planes of structural weakness, Bailey (738) says: The more important planes of cleavage in native cellulose are of two types: (a) those that are determined by the visible differences in density and porosity, and (b) those that are governed by submieroseopie faetors. The former planes are oriented parallel to the long axis of the porosities and therefore of the fibrils and are effective іп dissecting the wall into concentric or radio-helical layers and into elongated aggregates of fibrils. The latter are significant dur- ing the chemical dissociation of cellulose into fusiform bodies and other small fragments. He suggests as a possible indication of submieroscopie planes of weakness the angular ends of hyphal chambers of some fungi working within the cell wall. The cavities are oriented parallel to the fibrils, and the enzyme action takes place on planes corresponding to this orientation and on planes at an angle of 20-25? to this axis without respect to the more minute fibrillar organization. This angle corresponds to that of the planes of action of strong hydrolyzing reagents which dissect fusiform bodies from the wall, and also to that of planes of acetylation of cellulose fibers illustrated by other workers. Whether these planes of chemical action are significant in mechanical dissection is not known. There is a possibility that the saw-tooth tension fracture of the fiber wall that is some- times observed (Robinson, ’20) may be associated with this. In this type of fracture one side of each tooth represents a separation between the fibrils; the other makes an acute angle to it. MOISTURE CONTENT The increase of all strength properties due to drying wood substance from the green or saturated condition is pronounced. The theoretical moisture content of the wood at which the fiber walls are saturated and where no free water occurs in the cell spaces is known as the ‘‘fiber-saturation point.’’ This con- cept was put forward by Tiemann (’06). The practical de- termination of the point was made by plotting the logarithm of a strength property over the moisture content of the wood and 1939 GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 29 marking the intersection of the straight line representing changing strength values with the horizontal line represent- ing green strength. The intersection point varies insignificantly for different strength properties and for different specific gravities of the wood, but is considerably different among different species. Wilson (732) found a variation from 20 to 28 per cent moisture content within a small number of species. In listing these species by progressive fiber-saturation points those of similar structure were found to be grouped. The suggestion from this listing is that wood structure of different types, even within a single species, may have different fiber-saturation points or intersec- tion points. [Wilson, ?32]. Intersection points may also be obtained from the relation of moisture content to other variables. Wilson found the elec- trical-conductivity intersection point consistently higher for different species than those obtained by strength measure- ments, and much less variable. The discrepancies between the two methods are ‘‘possibly due to the effect of size and arrange- ment of elements of the wood structure on the intersection point.’’ It might be added here that the nature of the cell wall must have great influence in determining the intersection point for strength, since the factor actually involved is that moisture content at which the wood substance starts to become more coherent. Wilson points out that there are two factors involved in the strengthening of wood by drying, (1) the strengthening of the material, and (2) the increase in ‘‘compactness of the wood structure’’ due to change in volume. It is interesting to note in this connection that although the intersection points obtained from strength data agree fairly well with those from shrinkage data, the moisture contents at which shrinkage is first detect- able are consistently higher than the first signs of strength increase. This indicates that the mechanism of stiffening lags behind that of shrinking. The parameter, K, expressing the slope of the line repre- senting the relationship of strength to moisture content below [Vor. 26 30 ANNALS OF THE MISSOURI BOTANICAL GARDEN fiber-saturation point, varies not only among species but for dif- ferent groups of specimens within a species. It is not associ- ated with specific gravity. Its wide variability among different strength properties is illustrated by Markwardt and Wilson (735), who have tabulated a number of strength properties with the average change in strength values in terms of per cent for each 1 per cent change in moisture content. Some of these in- erements for spruce are: modulus of rupture, 4 per cent; modulus of elasticity (static bending), 2 per cent; maximum erushing strength parallel to the grain, 6 per cent; shearing strength parallel to the grain, 3 per cent; tension strength perpendieular to the grain, 1.5 per cent. Kollmann (736) has published comparable figures for Swedish pine: tensile strength parallel to the grain, 3 per cent, and axial compression (crushing) strength, 4 to 6 per cent. Pillow and Luxford (737) found that the strength of **com- pression wood’’ does not increase so much in drying as that of normal wood. Among the properties they studied, modulus of elasticity and tension parallel to the grain were exceptional in that their proportional change on drying was not signifi- cantly different in the two types of wood. The authors believed that the evidence was inconclusive in the case of tension, due to the insufficient number of tests. Excessive longitudinal shrinkage is typical of ‘‘compres- sion wood,’’ which is known to shrink considerably less than normal wood in transverse directions. The resultant effect, moreover, is a reduced volumetric shrinkage. Hartig (’01) gave an average volumetric shrinkage of 11.545 per cent for ‘*Rothholz’’ of spruce as against 14.55 per cent for ‘‘Weiss- holz’’ from the same stem. Trendelenburg (’31) found 8.88 per cent volumetric shrinkage for ‘‘Druckholz’’ of Douglas fir and 10.25 per cent for normal wood. Pillow and Luxford (’37) reported a slightly excessive equilibrium moisture content for **eompression wood.’’ In other words, air-dry ‘‘compression ооа?” contains slightly more moisture than normal wood under the same conditions. The difference, from their table of 1939 GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 31 air-dry properties, amounts to about 0.5 to 1.0 per cent mois- ture content. The above data indicate that the strength proper- ties of **compression wood’’ below fiber-saturation point may be abnormal not only because of inherent structural differ- ences but also because of abnormal moisture relations (col- loidal properties). With regard to the mechanism of inerease in strength on drying, Stamm (736) stated: The strength of a swollen fiber, in general, inereases upon drying. This is ex- plained on the basis of the secondary valence forces between micelles, which in the swollen condition are partially satisfied by mobile water, being brought together on drying and thus satisfying each other. This phenomenon is well illustrated in wood. He cited the experiments of Lüdtke, in which the tensile Strength of regenerated cellulose was found in different liquids : In such dry, non-swelling liquids, as benzene, the tensile strength is the same as it is in air. Liquids, such as water, glycerine, and formamide, that cause swelling result in considerable deerease in tensile strength of the fibers. Such liquids as dry ether and aleohol, which have a tendeney to remove water from the fibers, cause an increase in the strength of water-swollen fibers. Russell, Maass and Campbell (737) show that the strength of paper depends partly upon the area of contact between the fibers. Beating the pulp increases fibrillation, increasing the chances of contact and the strength of the paper. These bonds are held to be purely physical, and are shown to be affected by drying. The tensile strength of paper was increased from 0.69 to 7.28 kg. in drying. The same paper tested in the presence of methyl aleohol sustained 2.32 kg.; in ethyl alcohol, 4.63 kg.; and in propyl alcohol, 5.77 kg. These differences were given as examples of different degrees of loosening of the cellulose- cellulose bond. This suggests a careful reconsideration of the effects of extractives upon the strength of wood. These workers have offered a theory for the mechanism of drying of cellulose. Although cellulose is not soluble in water, the glucose units of the cellulose chain would be soluble in the regular glucose solvents if they were free. Due to this, cellulose [Vor. 26 32 ANNALS OF THE MISSOURI BOTANICAL GARDEN has ‘‘surface solubility" in water. Removal of the water causes erystallization bonds to be made between the surfaces of adjacent cellulose erystallites or single chains. Тһе surfaces are drawn together by surface tension and internal liquid tension, and this constitutes a deformation in the structure. Portions of the solid structure brought into contact by such deformations may become bonded together by recrystallization, if the liquid is one that сап form such ‘‘surface solutions" as were earlier described. Such is the ease with cellulose and water. [Russell, et al., ’37.] The above conception of the effect of moisture upon the structural cellulose of natural fibers seems valid, though it may serve as only part of the pieture of the mechanism in wood where at least two other broad classes of substance are pres- ent. Here there must be secondary valences or ‘‘surface solu- tion’’ bonds between cellulose and other constituents, which may not be affected by water as are the cellulose-cellulose bonds. A possibility suggested by the above theory is the draw- ing into orientation of some of the short-chain hemicelluloses upon drying, and perhaps their incorporation into the struc- tural system by adsorption. From this brief discussion of strength-moisture relations it may be concluded that the strength variations among different types of wood of the same anatomical description may not be quantitatively comparable as between green wood and wood dried to any given moisture content. Water must be regarded as a constituent of wood in its natural state, and its removal as comparable to the removal of any constituent. The course of the association of the remaining constituents during the gradual removal of one of them may vary according to the original composition. Thus when a condition is abnormal (statistically infrequent) in green wood it may be more or less so in dry wood at different moisture contents. Until abnormal types of wood can be classified and their drying constants de- termined, the most valid comparison of properties would seem to be based upon green material. For practical purposes two comparisons must be made, one at a moisture content repre- senting average air-dry conditions. 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 33 III. STRENGTH Тевтв AND PHYSICAL MEASUREMENTS This portion of the study was executed in cooperation with the Department of Civil Engineering, Washington Univer- sity, and was directed by Professor A. W. Brust of that department. For the purpose of this study the concept of strength con- forms to that in accepted engineering practice. Тһе tests fol- low standard procedure, with minor modifications as noted, and the results are comparable to other standard engineering studies of small clear specimens of commercial timber. Be- cause of the difficulty of making a thoroughly representative mieroscopie analysis of specimens of the size used in engineer- ing practice, special attention was given in this study to ob- taining specimens of uniform growth ring structures. Uni- formity could have been better obtained and the sampling made more certain by reducing the size of the strength specimens. However, as the size of the specimens is reduced there is an in- erease in testing errors due to undefinable stresses at points of loading and to unequal distribution of stresses by the spring- wood and summerwood portions of the growth rings. For this reason tests that have been designed by some botanists (Sonn- tag, '03, and Ursprung, '06) may not be representative of the strength conditions within trees or in large structural mem- bers, though the 1 mm.-square sections which they tested are admirably adapted to microscopic examination. MATERIAL The type of wood chosen to represent the conifer tracheid was dictated by its availability for personal selection of the green material and by the existence of comparable test data. Further, there were required logs of a diameter that would afford specimens without excessive ring curvature and with ! Mr. J. W. Graves, Jr., American Creosoting Company Fellow in Civil Engineer- ing, collaborated in the жи measurements, and ealeulations. He has used these physieal data as part of the basis for a dissertation entitled а" and re- lated properties of various growth structures in shortleaf pine," presented as а requirement for the degree master of science in engineering, raum 1937 (Vor. 26 34 ANNALS OF THE MISSOURI BOTANICAL GARDEN uniformity of growth. These requirements were met fairly well by commercial shortleaf pine produced in central Arkansas. A. Species.—Commereial shortleaf pine is wood of two species of Pinus which are marketed without segregation, namely, shortleaf pine, Pinus echinata Mill., and loblolly pine, Pinus Taeda L. Since selection of the growth-ring structure of the material entailed a rather wide survey it was not feasible to identify the wood in the tree except for two of the nine logs used. The identification was made on geographie distribution and bark characters. Only two species of pine are native in Arkansas (Turner, '35). They were separated by the color and character of the bark and the presence of ‘‘small resin pits 1/16 inch in diameter ”’ (Turner, 97) on the bark of P. echinata but not on P. Taeda. B. Source and Selection.—The logs were selected in the stor- age yard of а вахта at Sheridan, Arkansas. The source of the wood was within a twenty-five mile radius of this town, which is near the center of the north and south range of shortleaf pine and near the northern limits of the occurrence of loblolly pine, in this part of the southern pine belt. Departure was taken from the rule of the American Society for Testing Materials (733), which calls for taking consecutive specimens along cardinal radii of the log section without re- gard to structure. Selection was made for uniformity of growth, a repr tative range of ring structure, and for logs of large diameter. After a survey of the available logs the writer marked off a diameter on the selected ones. These were taken into the mill and a 2.5-inch plank was cut through each log at the marked diameter. Table т gives a brief description of the logs, and pl. 2 shows the structure of the planks. After the planks were dipped in ‘‘ Dowicide’’ (an aqueous fungicide), they were bound face-to-face in two packages and shipped im- mediately to St. Louis. C. Care and Preparation of the Specimens.—T wo days after sawing, the planks were placed in a moist cold-storage room 193 GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 95 TABLE I DESCRIPTION OF LOGS Number of Diameter Log No. Species growth rings (inches) 1 Loblolly (Pinus Taeda) 85 20 2 Loblolly (Pinus Taeda) 60 22 Butt log 3 Loblolly (Pinus Taeda) 30 16 4 Shortleaf (Pinus echinata) 75 16 Butt lo 5 Shortleaf (Pinus echinata) 200 28 Virgin growth 6 Shortleaf (Pinus echinata) 160 34 Virgin growth 7 Shortleaf (Pinus echinata) 100 19 Butt log 8 Shortleaf (Pinus echinata) 55 14 9 Shortleaf (Pinus echinata) 80 16 Butt log where the temperature varied between 32 and 38° F. The planks were immediately cut into two equal lengths, and one half of each was removed to the laboratory, cut into sticks ap- proximately 2.25 inches wide, and stacked for drying. The air- dry sticks were not cut into specimens until they had reached constant weight. The green halves of the planks were removed from cold storage, a plank at a time, and each was prepared and tested within three days. In marking the planks for cutting into 2.25-inch sticks an attempt was made to include only uniform growth within each cross-section, and the cuts were made, as far as practical, parallel to the growth rings longitudinally The longitudinal] rows of specimens included approximately the same growth rings in both the green and dry sections of the planks. The rough-sawn sticks were dressed by hand to uniform cross- sections approximately 2" by 2 ", with an open rotary planer (jointer). In this operation an attempt was made to true the sticks with the grain on all faces. The compression specimens were merely 6-inch sections cut from the dressed sticks. The tension specimens (fig. 3) were cut to shape on a band-saw, and then the small center test sections were dressed with a straight blade cutter head attached to a drill press as a shaper (pl. 1, fig. 1). D. Designations of Specimens.—Kach specimen is identified by a trinomial designation; for example, 4-A-7. Тһе first num- [Vor. 26 36 ANNALS OF THE MISSOURI BOTANICAL GARDEN SPECIMEN WITH SHOULDER CUTS MADE E el fo aton bond = | pe + |- е "^ ^ ё? COMPLETED SPECIMEN A р с | А z Ка 7 L ` N ! | ! У кі, UN с” 7 Е] 2 7 “2 SECTION АА’ SECTION 88' SECTION СС’ Fig. 3. Design of tension specimen used in this study. ber refers to the log and the last number refers to the stick or the longitudinal row of specimens (pl. 2). Тһе letter between the numbers designates the section of the original plank, eut in alphabetical order from the large end of the log. Each section was about 40 inches long, and the specimens were cut from it according to the suitability of the grain. Only specimens with identieal designations may be regarded as matched, although those in the same longitudinal row may have been influenced by the same general growth conditions. The influence of ‘‘butt swell’’ upon the wood may be present in the ** A"' and “В” sec- tions of Logs 2, 4, 7 and 9, so that these sections may not be comparable to other sections in the same row. Тһеге were bending tests and longitudinal shear tests made from this raw material in addition to the tension and compression tests re- ported here. TESTS AND MEASUREMENTS Wood is most often stressed in bending, in compression parallel to the grain, or in compression perpendicular to the grain, and there are adequate test data available in these strength categories. Though wood is strongest in tension par- allel to the grain, its use in this manner is limited by its strength in shear along the grain, and since this is of very low order com- 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 37 paratively little attention has been given by engineers to the longitudinal tension test. The recent introduction of ‘‘timber connectors," devices for increasing the area of shear at the ends of tension members, should stimulate more work on ten- sile strength in the future, especially in connection with elastic properties and in consideration of abnormal types of wood. For the present study the bending test has not been used because the applied force is resolved into longitudinal com- pression stresses, tension stresses, and shear stresses, which are unevenly distributed and undefinable for any certain area chosen for microscopic examination. The test for shear paral- lel with the grain would probably make a fruitful subject for the study of variability in wood, if it were not for the fact that no test has been devised in which longitudinal shear is known to be exclusively active. The tension test and the compression test parallel to the grain are most easily understood, and the type of internal stress working on the individual fiber may be inferred. The fibers here are put to their best advantage, affording the best possible comparison. The stress in these tests is based on the transverse section of the wood which most truly represents the volumetric characteristics, 1.е., descriptions and control data taken from the end section apply to the region of actual failure. A. Tension Tests.—For the same reason that wood is rarely used as tension members in structural work, the testing of small clear specimens in tension is difficult. Since wood is about twenty times as strong in longitudinal tension as it is in longi- tudinal shear, the specimens must be designed to create enough longitudinal shear area to bear the load that will break the small section in the middle of the length (fig. 3, BB’). Further, there must be provided a gradual reduction in section area from the shoulder (CC’) to the test section to reduce the possi- bility of a concentration of internal stresses that will cause failure outside of the test section. Kollmann (’36) has illus- trated a wide variety of tension-specimen designs proposed by different workers and used in different countries. The type of [Vor. 26 38 ANNALS OF THE MISSOURI BOTANICAL GARDEN specimen used in this study is identical with the standard in American practice except that the test section is reduced from six inches to three inches in length, and from (9$)? inch to (15)? inch in sectional area. This specimen has been found to have the advantage of being less subject to damaging stresses in handling and less likely to fail in shear due to slight spiral or eross grain. In spite of the care taken in preparation, some of the specimens failed entirely in one of the tapered shanks, or failed in tension partially in the test section and partially in the shank with longitudinal shear connecting these fractures. When fracture did not occur entirely within the test section it may be assumed that the maximum stress given is conserva- tive, 1.е., the section had not yet sustained its breaking load when failure occurred elsewhere and ended the test. Тһе elastie data, however, can always be taken as valid, since the strain measurements were confined to a two-inch portion of the measured section and were not affected by stresses and strains in other parts of the specimens. The area of the test section was computed from mierometer measurements to 0.001 inch. Testing was conducted on an Amsler hydraulie testing machine (pl. 1, fig. 2). Тһе load was applied to the shoulders of the specimens (fig. 3, СС”) through split steel rings with one-inch-square center openings which fitted about the shanks. These in turn rested upon spherically seated rings which transferred the load to the head blocks of the machine. Load was applied at an average speed of 0.007 inch per minute. Strain was measured with a ‘‘Last Мога” extensometer reading to 0.0001 inch. This device measured extension over the middle two inches of the three-inch test section. B. Compression Test.—The specimens for this test deviated from American standard practice in being six inches in length instead of eight inches, although they conformed to the 2” x 2” cross-section required. The ends of the specimens were sanded smooth and square, and length was measured to 0.01 inch with a steel scale; section dimensions were measured by micrometer to 0.001 inch. These tests were made on a Riehle three-screw 1939]. GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 39 testing machine of 150,000 pounds capacity, equipped with a spherically seated head block. The testing speed was 0.024 inch per minute. Strain was taken as the distance moved by the head block and was measured with an Ames dial reading to 0.0005 inch. This method deviates from the recommendations of the American Society for Testing Materials which require strain to be measured between points six inches apart in the middle of an eight-inch specimen. Тһе unit deformation over the full length has been reported to be consistently larger than that derived from the recommended method, and, further, the modulus of elasticity based on full-length deformation is better related to maximum strength (Brust and Berkley, '35). C. Specific Gravity Determinations.—Specimens for spe- cific gravity applying to the compression specimens were cut from the sticks near them. In the case of the tension tests, specifie-gravity specimens were cut from unbroken portions of the 0.5-inch-square test sections of the tension specimens. If the test section had been shattered, a block was cut from identical growth rings traced into the shank. The data for the determinations were obtained by weighing the blocks in air and in water, with a correction made for the water absorbed during the immersed weighing. Immersed weighing was done with a balance on which a weighted cali- brated wire frame was substituted for one of the hanging pans. Specifie-gravity values were referred to volumes as tested except for the air-dry tension test. It was found impos- sible to weigh accurately the dry two-gram blocks in water because of the air bubbles collecting on the wood due to dis- placed air. Specifie-gravity determinations of both green and dry tension specimens were based upon their volumes in a re- soaked condition. All specifie gravities were corrected for benzol-soluble extractives; this tends to equate heartwood and sapwood. D. Per Cent Summerwood.—Although the percentage of summerwood is not used as a correlation factor, a visual esti- mation is recorded for the compression test specimens, and a [Vor. 26 40 ANNALS OF THE MISSOURI BOTANICAL GARDEN value for each of the tension pieces was obtained by plani- metering. This latter value represents the percentage of sum- merwood in the entire cross-section and may differ consider- ably from the proportion in the average growth ring, especially in wide-ringed material. E. Moisture Content.—For green specimens the moisture content was derived from the specific-gravity specimen in the stick section of the same designation. This constituted merely a check against the possibility of the tested wood having dried below the fiber-saturation point which Berkley (734) found to be 22.5 per cent for southern pine. One-inch sections were cut from the air-dry specimens and weighed immediately after each strength test. For the tension specimens this sample was taken from the large end of one of the tapered shanks. F. Longitudinal Shrinkage.—Since this is the only physical property on the basis of which ‘‘compression wood’’ may be quantitatively segregated from normal wood, a series of these measurements was made in this study. For this purpose a four-inch section was taken at the mid-point of the original plank for each longitudinal row of specimens. This sample may be assumed to be fairly representative of the “В?” and “С? specimens, but it is likely to indicate less shrinkage than is actually present in the ‘‘A’’ specimens and more than the “D” and “Е” specimens. Especially is this so for the butt logs 2, 4, 7, and 9. This follows the findings of Pillow and Luxford (’37) that ‘‘compression wood’’ is much more fre- quent in the lower seventeen feet of shortleaf pine trees from Arkansas than at greater heights. А 1" x 1" x 4"-piece was cut square with the growth rings from the 2" x 2" x 4"-sample, the ends sanded, and the center points marked. The difference in length from green to oven- dry was obtained by means of dial gauge reading to 0.0005 inch. The physical data are given in columns 2 to 10 in tables п to v. The specimens represented here are those remaining after careful inspection had eliminated those with irregularities in gross character that might influence the data on ultimate 1939 GARLAND— WOOD STRENGTH AND MICROSCOPIC STRUCTURE 41 strength or stiffness. The strength figures given represent two aspects of the resistance to stress: (1) the maximum load that the material is able to bear, and (2) the resistance to deforma- tion or the stiffness of the material. The modulus of elasticity represents the load required to lengthen or shorten a specimen, per unit length of the loading axis during the time the material remains elastic. 'This then is a measure of the stiffness of the material within the range where releasing the load will return it toits original form (length). Stiffness is included in the gen- eral term ‘‘strength’’; however, in the indexes given in this paper ‘‘strength’’ indicates maximum or ultimate strength, and ‘‘stiffness’’ refers to the property evaluated by modulus of elasticity. The strength-density index and the stiffness-density index of the wood refer strength and stiffness to factors other than specific gravity. If these indexes were multiplied by the specific gravity of wood substance they would give the stresses for the wood substance according to the argument presented above under ''Density."' IV. ANALYSIS THE EFFECT OF GROWTH RING WIDTH It may not be assumed from fig. 2 that growth rate in itself has an influence on the strength-density index, since no data are given on the variability within any growth-rate range. It is indicated that low strength is more likely to occur at more rapid growth rates regardless of specifie gravity. Тһе low average strength in wide-ring classes might be due merely to the more frequent occurrence of abnormal wood in them with random choice of specimen. Figs. 4 to 9 present the distribution of strength- and stiff- ness-density indexes according to growth rate for the material tested. Considering the distribution of the individual speci- mens it is obvious that the correlation between axial strength properties and growth rate is poor. Large variations occur well within the growth-rate range acceptable for structural purposes, and many wide-ringed specimens show excellent [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN 42 “mor eq Хеш enpsa sty} “пәппоәбв 943 zo uorjoes рәлпевәш ƏY} ортвјпо роллпооо 9114981} эфвотрит вов}, “Әшір ut uorsuojxo ив sogruZis (-) 1 'sueuroeds 4389148 ,,0,, pu? ,,Ң,, 943 чеомјод пәле) әләм sueuroeds әчү, | 'OATj9UI)XO [OZUOQ 10; рәҙәә1109 SI Ата 18 ogroedg , 80% тРа cost 02017 00012 0668 “ғ Gg 8? EZI Lov T-0-6 80€' $08 9251 199 006'21 009%, OFE'I I8 0% 90T ore TV-6 135" GFI 011% 0661 008‘58 006'91 815 оф 9'G тт egy 8-0-6 eeg raris 2951 6т/. OFS‘FT 1144) 824 69 8'8 16 I6*' £-V-6 вет” 08 022% 0022 009'те 09991 880' 6$ 6% ect gos 3-9-6 926 0`6Т оот'а сет 008'8T 08701 Lgo - 83 eg сот oss’ 5-У-6 ear 0% 090% egoz 009FE MA 680° ОР 9% 021 Tos" І-0:6 ГА 14 ЕРТ 0862 0L*'T 008%22 092 1Т 8:0 — 8? es LIT Eet Т-У-6 09T 26 029% 099% 009'5$ 00987 350° IS L9 FII 890 ғ-0:8 68Т` GOL 089'2 90671 0c1'ce 029%9Т 690: У? 0% SIT Tes" 5-0-8 oa" РТ 022‘ ОРРТ 00226 00% FT 680° 38 8'9 681 StF 1-0:8 66r “ТТ OTT‘S 068% 00026 099'9T €10° IS FST 82 999" 9-У-2 16ё` 0'ec тебт 09Т“1 006'91 OFT‘OL 8er 53 3'9 82 009* TY ве“ 9'er 929% 0661 000'те 000' 4T 090-і 88 0°бТ cg 6Р9' 2-У-2 eer 0'8 028“ 0%62 09%82 092 %Т т30° 1% 97 TOT Tos" 2-9-9 6646 8702 000% 116 000'61 099% гто' 9? 26 921 ocr 6-0-% ces’ 9'6T 090% 09071 001'6I OOT‘OT 992: 29 6% SOT 824 РО» Gee 9'6T 0212 386 00€'cT 028'9 FFs 78 69 $5 OFF 60% ost 9'8 08+ 028'Т 006'22 091'7I 880' 15 g'or 9g Sit e-q-* £6r тп 0re'e 02.21 000'48 002‘0T oot 22 89 LIT 968° 9-9-8 696 eS 089% CLIT 022:8Т 05/48 IS? ге Lg РЕТ 08Р' Т-У-8 eve OFI 00т“& 0581 00022 00€'TI OIF 73 LA FII 16* 1-0-6 ETT “9 0128 028“ 00265 000%9Т 280 GG v9 OTT 629' £-0-6 esr OL 092% 0922 008% 00081 350° 0% 0% 60Т Tee 20-2 EFT 28 096% 0281 09295 |,.08Г21 Tso” · 88 r9 SIT 937: DS (799/18) (ш/а | (сш/өа | (99/12) (euis) |(вәәлдәр) 000Т) 0001) (,ut/‘sqr) | (гит/“ваг) (25) (25) (25) |(Сәә/428) (2) 109 (2) ‘Joo uourroods 142тәм роомлошшпг ————— 1 u32uo[ jo волт Кір-пәло | ,ouin[oA пт потуеўпәтло (6) 109 Á31or3se[o (1) тоә q32uo138 19918 JO 0014298 yout 194 | Јо 0џәә uoo1d теплу јо *xoput jo ‘хәрш 915993 4180 тәй ut -88019 ЈО ssuli ied ur | по peseq |ueurroedg o[Zuv э8в1элу ХКүвпәр впро Á31suop agew | әЙеңшіцв | quo? 194 ur | чјмоло | 3uojuoo | 414—183 ЖЕГЕ) 91401 -433 4913$ [gurpn3tZuorT |роомлэцтийс әлїўвторү | ogroedg (тт) | (от) (6) (8) (2) (9) (9) (+) (е) (2) (т) Nüduo беч II 47114 VL NOISNGL 'IVIXV 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 43 “мот eq Хеш әпгвл sty} (пәппоөйв әц} jo uorjoos ролпевош OY} eprsjno PAIMIO oinjowig озвотрит SITEIT ,, "Заир ш uorsuojxo ив вэцти 1$ (—) 1 'sueuroods 43819148 ,,0,, PUB ,,Я,, 943 поомјод пәле әләм впошпоодв ou] | 'олтдовлухо [ozuoq Surjonpop Aq ројодллоо вем Кулъі8 ogroodg , %66 282 076'5 15271 0S0'cc 00€'TI 9LF 6? 2% 68 ISF ғ-а-6 ost’ 9'8 ors'a 09%2 099416 00F TI 680 - 0% 88 се” 1-4-6 938" 0`61 09?'& 0991 00% 25 00221 C30" 9g L9 L8 SSF РУ-8 662” FLT 021% OFFS 00£' 18 00Т:22 190: 09 £L 1'6 569' е-9-8 20% "A 008'g 0813 000‘08 00891 890: 98 8'L 96 096 5-У-8 ose $05 Ost‘ 0821 0088 026%9Т 690° ОР 52 26 900 Т-У-8 86" FII 097$ OFFS 004'ee 00%8Т ето’ 1% FET FOI 9re' 9-9-2 963° ел 002'2 OFS‘T 00625 ШУЖЗ! ger 15 ғ6 ZO OIF Р8-; 808" 6'4T 062% OLLI 0Se'vG 001'81 180° -1 87 гот 8'01 889 ed 220 8`61 02%2 0992 00826 001'91 T90* оф £4 06 16% 5-У-9 80r 29 006% ОРТ“ 00922 004'€T 200" ғе 0781 FOI 16ғ ғ-а-% 780° 8% 0$9'8 062% 00% 62 009%Т 690 те FSI ет 367’ £9 РО" 1211 096% отет 00826 008 %1 210' 65 ғ. 66 TSF 3-У-Р ооё” 8TI 018% 268'1 00262 009'Р1Т РРа' 0$ 94 2'01 16%” £-V-* вет” 08 018'8 026% 008 ФР 00922 920 98 O'ZI 6'01 509' Iwt 608" 0'8T 008% 0%9Т 007476 004'eT 020: 17) 8T 8'6 oer 9-А-8 Ore" 6°61 019 $28 0088 OOF LT 390° 69 0% 8'6 619' 5-0-8 822' 8'er 048'G 003'5 009'9* 09861 1s 18 Ре 96 92%” Т-0-8 20% OLT 3388 OTST 00c'ac 09221 002: те ға FOL 08*' 1-Я-5 879 c'eg 027% 06<Т 09672 008 %0Т IST 78 се 90Т 90% 9-У-5 LIE 602 067% OF9'T 001'92 00%8Т 290° 02 ғ? 6'01 PZS £-V-6 ZET РЕТ 090% 021% 00092 0£6'eT 920 38 ee TOI ree eqs Ctr’ $'95 90£'c 9001 00202 092%0Т 628' T9 9% TOL esc" 6-0-Т 68€ 622 Ж 0g2'T 09/22 00621 PSL" 19 9? РОТ 10% TOT See 9°61 0292 в82ғТ 00% 22 000'€T 00€'T се SL FOI TIS 8-0-1 PET "Y 0298 006% 00266 |.«096'9T TS0° - гот 00Т LOF гат ('29/'18) (сш/за | („гш/'вај | C99/22) (ours) |(в9918эр)| 000Т) 0001) |(сш/ ат) | (eutsan) (25) (25) (49) |(әә/і8) (2) 109 (2) 109 uourroods 149тәм роомләшшпв — і122ләТ jo воле Arp-weao | ,oumn[oA ит uorjejuorio (6) ‘Joo | £3ronse[o ( 1) 109 | ЧуЗиәдв | поола јо uorjoos | цош 1од | Јо шәә | пола теплу јо *xopur 20 “хәрпт Ә[1809} queo iod ut -88019 10 58011 194 ur | uo peseq |ueuroodg e[duv эЗелэлу Азтвчэр втпрор ÁK318uop әұвшт | eSexurigs | quod 194 ш | q3401r) | 3uojuoo | Ayav -8Sougtg -ц3809135 [eurpn3tZuo'T роомлошште) әдпјѕтоуұ | ogroedg (тт) (от) (6) (8) (1) (9) (в) ($) (е) (2) (D AUG-UIV 'SLSHL NOISNGL 'IVIXV III W'IS8 ViL [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN ert 0702 9001 оре 0g1'9 0ee'e 680° – ст FII 9° ere £-Y-L Р8Т' g'or TL8‘T 0207 ОРЕ“ 000% 0с0-і 0$ 6 IT cg erc ev 688" 8`61 69F'T ред 027% 027% 980° OF 0% 92 Chr Lag £9£' 612 ізет 019 0869 ОРТ“ 0?0` os 1% 0€ ESF 9-Я-9 вет' 0'8 871 818 OIL 086% те0' 0$ 8'8 TOT 9LF 2-9-9 sit 8'9 60т:2 00 073'8 037? C00" се CLI те 120 Fag esr OL 18971 506 092'6 0288 280' OF 522 62 ege е-9-6 тет” L8 86<Т ғ06 OFL‘L 08 87 er LT 59 996” 2-9-6 ost’ 9'8 А. 682 O61‘L 0т6'2 ето" 0$ 98Т cg 14454 ras Г OL 261 094 0269 092% 880 са 68 9$ 864 eq Sor’ 24 сета 356 01/8 02276 940 35 921 081 eer TIF ста' Рат v81'1 $21 0624 ose‘s СҮ ср ТФ PEL РЕР" rv-e сот’ 09 01671 216 028"; 0c4'e 290° 0g 64 OIL 81% с-а-2 LST ғот 0291 064 0ё8'/ 018“ ezo се РР 601 Ј8Р 5-а-3 LLU eor 06<Т 651 02%4 0878 350° 0g 6% Fel ве? т-а-2 беге - E 019 008'9 0778 628' oc 0% 89 902 с-9-Т е 8782 090“ #09 0r9'9 084'€ PSL 09 L'e 09 699 rat - - 628, cos 062%. 061% 0%91 о; 0'9 38 949 ev OFT Р8 ВРТ 922 025% 092% I90' са 0L STI FPF Tat (20/'18) (eusar | (ұш/өа | (99/18) (әлів) |(seeiSep)| 000Т) 00017 | (zur/'sqp) | (eut sqr) (25) (25) (25) |(әә/48) (8) 109 (2) 199 " чу рта on 34319 роомлошштпв ------- 4 q ӘТ 43 мо 20 -ПӘАЛО 9uin[oA 148001116160) (6) 109 Кутәт}ввүә (4) тоә 43809148 пәә18 Jo 3492 1ed ut | цош ләй | Jo 3uoo "woo13 I9[[uqg јо “хәрпт 20 “хәрпт ZSurgsnio | juoo ләй ит |роомлошштве| 68011 лод ut | uo peseq |uoauroodg o[Zuv oSve19A y Аувпор парой Аувпор unuixeW | э8зчаыЧ5 jo рл qmo | 3uojuoo | Apaes -S89UgtUg -439 4913$ [gurpnjriZuor[| рәувппцен oinjstoy | оџоода (тт) (от) (6) (8) (2) (9) (с) (Ф) (е) (2) (D NAJUD ‘SLSAL NOISSOWUHdWOO 'IVIXV AI W'IS VIL 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 45 "ЗитАлр ит uorsuojxo ив вэцта 18 (—) | "впоштоодв 43919138 ,,0,, PUB ,,Q,, 943 пчоомјод пәңеҙ әләм впоштоодв OSeyUTIYS eu | *QATJOVIJXO [Ozuoq 10; ројооллоо st  ALI ogroedg , 88* 262 0507 TOS 096'9 026% OFSET ср г? 90T LLY StF 9792 196 Т6? oreo 092% 82/7 08 ғ“ 16 ЕТ“ eer 0'8 029*Т 811 06,4, 0096 680° 38 ғ? 021 Zor" МТ eor беғт 789 026%, 096 880° — се. о? LIL LAW ота' Ter 026'T $96 0226 028% C30" OF 9, FIT 66* TIG 261 ££9'T 186 066'8 069% 190 OF £L FOI TES 86r FII CIOS 376 0c0'6 085$ 680' OF 9'8 62Т 69% РӨТ" СТТ РЕР Т 858 0%9%. 092% ETO о? L'ST 8; Lee 802: OSI 02%Т 768 117547 068% 180 – 09 “от 08 880 1152 04€ 080'T 689 08*'9 ors'e 8er 08 079 82 26% (799/18) (сш/за | (ош/ва | (99/18) (әшів) |(воолдор)| 0001) 0001) (zu1/:sqi) | (cur/:sqr) (25) (25) (205) |(99/:13) (2) 109 (2) 109 цара Suri ЗЧ том pooA1ourums = {933991 43м^018 Јо Кір-аәло | „ошпјод UI U01j93U9LIO (6) ‘Too | Ауопевје ( 1) 709 43349135 uoo1d jo queso лод пт | qour ләй | jo quoo пәә12 телф јо ‘хөрш 20 *xoput Surnsnio | juoo 194 ш |роомлошштве| 88011 iod ut | по ровед a[sue ode1oA y Күвпәр зпарои\ Кувчэр | unue | eZexuriqs jo арм цалол) | даәҙаоә | ÁjtAv1d -5590 18 -ц3809139 ||eurpnatZuor[| рәўештв{ олтувтор | 9ogroedg (ID (6) (8) (2) (9) (е) (+) (е) (2) (от) 22 теме 3% uio die d ооо ЕЕ DMDDAAAA чо Ф <<< —— uouiroedg (penuruo)) AI W'ISH VIL [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN 46 Р60' Ра 026% 0861 008‘ST 0gs'or 920 се 6'03 6'8 199 5-а-3 cor” e 096'5 1291 06/2 006'8 €10° ОР РРа 9'8 coc" таг 9/2 079Т OFFS 08e'T 000'9T 0206 993° 38 2% “8 990 rv 9ст' 0'6 0$9'8 084'T 001'6T 022'6 880° Gg 9'8 Р8 68Р' ed IST L8 0922 OLL‘T 0€0'8T 009'6 920 се 6'01 42 920 Т-У-? See 9'€r $96 сдет 006 %Т 092% оот' 02 1% ғ8 88ғ 9-4-Е LIS EFI OFFS 0861 009“ЄТ 026%9 020: 0$ ot 0*6 SIG 3-А-8 cog 8'II 090“ ose‘T 000'9T 022% 810° 02 0% 98 ТОР $-0-8 802 OST с00% дет 029'9T 050'8 390° се eg 9'8 68? 2-0-8 0sr 69 OFT‘S PLST 0L8°ST 026% IS? 08 Lt 48 206 т'0-е FPS ТҰТ 029% LOFT отт 02%8 EZT 3$ 1% 6L 099" 8-V-$ 09£* тта 59671 ост'т 028' 21 0218 002” ОР 2% 87 989" 1-9-6 92% 292 9841 000'T 0ge'er 06*'L тет: Gg 5% 2% 199 9-V-6 220 8°31 СРР“ 20€'T 008%Т 0176 390° 38 rS 8'8 9I9' £-V-6 6er 0'8 Оре" 899'Т 08e'er 029'6 20: 38 е? 877 819° eq eor “6 0292 0281 08Z‘ST 0276 920 38 YS £ 08% ras L6*' 8762 0821 OTO'I 008'&Т 009%, 628" 09 es 8'9 89€ 9-0-Т £97 922 088“ 080“ ОР8'ЕТ 022% 791" 09 9% PL gcc’ РОТ 897° 6:22 8Р8Т 2901 дар ет 029%, 0%9Т 02 UA 68 059" -аст 80r 29 0923 ОРРТ 008'eT 092:8 TSO 08 отт el 220 т-а-т ('20/'18) (сч/ва | Cursar | C99/18) (outs) |(вәәлЗәр) 000D 0001) („'пт/°ват) | (zur/:sqr) (25) (25) (95) |(99/:18) (2) 109 (2) 109 qjpra Burs ЗЧ тол роомлошипа ----- 1 u32uo q140418 Јо Кір-пәло | ,oumoA UI п014е409110 (6) 109 | ponse | (4) oo 43909135 пәә12 JO 3999 194 ш | цош ied | јо 3uoo | Алр-ле тепчү јо *xopur 20 *xoput Surqsnio | 1190 дәй ut |роомдошштпв| в8аы 194 ur | wo peseq |ueumoedg әүЗив одвлолу Күтвпәр вптароут Ayisuep | unuixeyy | oseyuriys jo чарта цчамоло | )пәҙпоә | Aprang -ввәп 18 -ц380923$ Тетра ао] | ројештвл 91njstog | ogroedg (тт) (от) (6) (8) (1) (9) (с) () (е) (2) (т) AHG-HIV ‘SLSHL NOISSWHHdNWOO 'IVIXV A W'IHVIL GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 47 1939] 'Sur£1p пт потвпојхо из sogrudts (—) | “впәштәәйв 43819138 ,,)),, PUB ,,Я,, 91) поомјод пәҳез әләм впәштоәйв oSvxutiqs oq] | 'оатовлухо [Ozuaq 10g ројооллоо st ÁjtA€1d ошоода , LOF 0%2 680% 386 002'er 00%9 SLF 0% 9% £'6 ФР ғ-а-6 256 9702 088% 091'1 0£c'er 0Р2'9 813° 0% 98 26 60% 8-Я-6 080° 9% 0cv'e 007“ 099'GT 0Р2“, 680° 0g 8% r6 L6*' 1-4-6 voe 6'8I 0%22 0861 девет 069'8 920 ср 2; SL 919° РУ-8 тег" €'6r 052% 021 0ce'er 029'8 £90 03 rs el 189 5-У-8 908" SLT 022% 0/21 00/%Т 0278 Ұ80 о? 6'2 т8 alc’ ГУ-8 TOS Т OTIZ 09Т“Т 006%Т 005% 8er 08 62 66 6Р9' с! cec РЕТ 0re'c OLST 006‘£T OFT’ 680° – 0g YL тот 980 £-H-4 бРа' FFT 089g 0041 0%2 ‘FT 020'6 090-і Фр 26 86 669 2-9-2 102: 9'II оғо“ 9221 OSI‘ST 078'8 920" 38 8 TI £'6 Р89' Т-Я-2 926 0°6T 059% FSI'I 03L‘ST ОРО, 980' се ғ? UII ғ 1-У-9 635° 0721 00%2 сс 00% ЕТ 000%, 0%0" 38 3'3 L8 85$ 9-V-9 Secr SL 001'e OI9'I OSE'ST 066% 680° cE 6% 06 029" £-V-9 Рат EZ 027% чет 00S‘ST 009'8 Tso" GF v6 6'8 80” 2-У:9 580 FEL 099% 00s‘T 008%Т 0568 €10° се 59Т “6 295 6-0-9 180 072 0r0'e 2241 092421 OOT‘OT £90* 0g Аа ба 26 egg £9 ('20/'18) (eusar | („1/'вај | (99/12) (ours) |(вээл8эр)| 0001) 0001) (,ut/*sqq) | („'1/'ва[) (%) (%) (%) | (100/718) (2) 109 (2) 109 qjpra Burs у48том роомлошштв === 1 uuo (324018 Jo -пәло | „әшпүол UI потувупәтло (6) 109 | Ауготанје ( L) ‘Joo 93809148 09918 JO juo?» әб пт | qour ләй | јо зиәә | Жір-пв 161245 JO “хәрит jo *xopur Зитцвпло | 4499 1э4 ит |pooaieuruns| 83011 ләй ur | по peseq |uourroodg 918 ив одвдолу Азтзиэр sninpoq Аувпор | wnurxeyy | eZexuriqs Jo ҷурм morg | 4пәјиоә | ÁjtA91d -ввоп 114$ -439 49149 [eurpnjtguor[| рэ 138: əƏInysto | 9groedg (тт) (от) (6) (8) (2) (9) (3) ($) (е) (5) (т) (penunuo)) A AIAVL [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN 48 strength properties for their densities. Although a larger ran- dom representation would perhaps show that there is a con- centration of ‘‘abnormal’’ material in the range of wide rings, it is not indicated that width of growth ring in itself is a con- siderable faetor in the resistance of solid material of the wood to axial stresses. Since data on tension strength are rather rare in the litera- ture these charts are of interest in comparing the tension and compression stresses under different moisture conditions con- sidering the data as groups of specimens from the same lot of wood. Any solution for the true mechanism of stress re- sistance must consider the faets shown here: that in the green condition axial tension strength of the wood substance is more than twice as great as axial compression strength; and that drying has less effect upon tension strength and stiffness than upon compression strength and stiffness. [tH hem р EM ТЕТІГІН ГИР НЕНІҢ BESEBEBARBSESEERERBERBSSBESBRABRRS РЕНН папапалавв a = | HH ТТТ LH ӘННЕН аза аг зеваваава и LIT] LLELITITTTTITI p HTL-HH EEEHHRHEH MIT везавиг низова 2:8252225555222412225:12%452522 eae LLL апа! 25512222221) RHENUM o m ЗЕН НИ НННП ИН НЕ ни КЕШЕҢНЕ | = ша EUSDUCEHBHUIS H | XIAN! A1ISN3Q-H19N34.1S 45 о gravity) Fig. 4. Axial strength-density index (ultimate strength -- specific plotted over growth rate for green specimens. 1939 GARLAND— WOOD STRENGTH AND MICROSCOPIC STRUCTURE 49 The normality of the wood used in this study may be judged by comparison with the average data given by Markwardt and Wilson (735) for Pinus echinata, taken near Malvern, Ar- kansas. The average maximum crushing strength in compres- sion parallel to the grain in green condition was 3570 lbs. per sq. in.; the average specific gravity, at test, was 0.477, and the average number of rings per inch was 13.4. These data LL] ase EELELELII тааб! LLLLII ÀLLLLELLLCLLLLT LÀ төере БЕНЕН. va 5 LI m З 8 STIFFNESS -DENSITY INDEX 0 5 RINGS PER INCH Fi Axial tension stiffness-density index gena of elasticity ~ specific gravity) ‘plotted over growth rate for green specimens [Vor. 26 50 ANNALS OF THE MISSOURI BOTANICAL GARDEN are comparable to those of the compression tests used in this study and when calculated into an average strength-density index and plotted in fig. 6 are seen to fit quite well. Тһе point is represented by the X mark at 13.4 rings per inch. CORRELATION OF STRENGTH AND STIFFNESS WITH FIBRILLAR ORIENTATION Since low strength for its density is known to be accom- panied by high angle of fibrillar orientation in ‘‘compression Fig. 6. Axial compression strength-density index (ultimate strength -- specific gravity) and stiffness-density index (modulus of elasticity + specific gravity) plotted over growth rate for green specimens, X indicates strength-density index of average test for Pinus echinata from Arkansas (Markwardt and Wilson, '35). 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 51 "wood," the present randomly selected groups of specimens were examined to show the effect on strength of this measur- able feature of cell-wall structure. This relationship for com- pression strength, bending strength, and stiffness has been treated briefly by Pillow and Luxford ('37) and reviewed earlier in this paper. Fairly simplified technique had to be developed to obtain representative averages for the comparatively large amount of material involved in this study. Sampling was done in the following manner. Blocks of material from the test specimens were cloven radially. Under the proper lighting angle there ПНЕ: ЕН iin | m RAZ ЕН pues EEHEHE HE в пн: НАНЕНЕНЕН EEEHEEHHHH e E Е HB B: STRENGTH-DENSITY INDEX ГІТ RINGS PER "m Fig Axial tension strength- density index (ultimate strength ~ specific Pons ‘plotted over growth rate for air-dry specimens. [Vor. 26 52 ANNALS OF THE MISSOURI BOTANICAL GARDEN could be seen on the faces of the split halves small radial groups of fibers, often one cell thick, whose ends һас been loosened from the wood. These one-celled rows were carefully cut free with a micro-knife and placed in benzol. When the benzol had displaced the air in the cells these ‘‘sections’’ were put in temporary microscope slide mounts in ordinary rubber cement. The non-swelling medium was designed to prevent E HETT TITTET IBRRREBERRARERA Е т РЕНЕ ЕНЕН ә НЕН ЕЛІ ТЕШЕ jum T: з ЕЕ. ‹ TIHH E 8 НН nsa иша a в ЕЕЕ ЕЕ +44 ED HIR ЕНЕН ЕНЕНЕ: ____ STIFFNESS-DENSITY INDEX 10 RINGS PER мн Fig. Axial tension stiffness- "density index (modulus of elasticity ~ specific gravity) plotted over growth rate for air-dry specimens. 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 53 the disappearance of any fibrillar checks or striations осса- sioned by drying. The search for indication of slope of fibrils was made at 440 x. Often the plane of orientation was indi- cated by cleavages in the central wall due to the splitting of xim: E ET pum nnum Hen : НЕ ЕН ЕНЕН | ЕН Банн асса se LII E HH [| ГЕННІҢ елегіш ШШШ c ENS НЫНЫҢ STIFFNESS-DENSITY INDEX SHE EIE Enn ШШШ ШЫ — | | 4-14 e + Se СІЗ а ax || ЕЕ SION. AIR-DRY : AIR-DRY ви HHH STRENGTH-DENSITY INDEX 5 HHH 885452255955: 88222522525 шен БЕСІН 10 15 25 RINGS PER INCH Fig. 9 xial compr mn Туге ый density index (ultimate strength — specific gravity) Ne stiffness-dens x (mo odulus of elasticity -- specific gravity) plotted over growth rate m 1. ae specimens. [Vor. 26 54 ANNALS OF THE MISSOURI BOTANICAL GARDEN the wood. Summerwood fibers of low angle were the most dif- ficult, and often considerable searching for a single measure- ment was entailed. In difficult observations polarized light was employed to accentuate discontinuities and to check orienta- tion angles. Measurements were made by means of a cross-hair and a graduated revolving stage, and only in the clear, i.e., away from pits and rays. The average angle for each specimen is based on twenty measurements distributed as evenly as possible along the split radius according to the relative thickness of the sum- merwood. Тһе tension specimens had more complete repre- sentation since they contained fewer growth rings. Many compression specimen rings were represented by a single measurement which was taken from about the middle of the summerwood. c x - ++ И ми -o : а зз а -= || ес а АЕН E кеш EHEER апанаваяав ЕЕ € ШЕ z Го ЕНТ Hi НЕНЕН и ма ЕЕЕ АН: @ d к. ЕЛЕНЕ . SUE STRENGTH-DENSIFY INDEX | БЕН БЕН uis EE Cp ЕЕЕ [d nn - с SINE OF FIBRILLAR ANGLE Fig. 10. Axial tension strength-density index (ultimate strength ~ specific амаг eorrelated with sine of average fibrillar angle іп summerwood for green specimens. и ro "5 — ташы Li 1 [11::| | BESESBRONENSEBRRPURRENM! 8 ЗЕ ннн = LI 20 - as " LLLLLLI E [+ = BIS SEs puri [uu ЈЕ HOS н 0 ПН А Eu o Hoog 2 92222252415: - : uw BG dune Е Bofiug ae "9 КЕ с ЕН ia HI о = «и и 9 i ь Eos on o ааты Ф ӘЗ oot © 50 Ф = Li (2) — 8 ci a ы w © d org gs Р 5 О БАРЕВЕ E Ta boo oH а 22 © ро а Е с, ч ш Рона — = Ф Ф oe c m . 2 Opa, Б д aP © m = Bag [25] 2g m б © = ап а-ы a о. Жаы, Ф = S язве Е б * 4- E „© 3 d Ф 9 5 + Ji = >= д 9 ЕНЕНЕ д [ = 5. € qq ННН Е > Ф = te Ф > LLET HHH : а Но" ES È i н соЧеня H 1 > о E S n 2 = coo H 4 c 5 “ж Z e 2 : e Be uu = яя Я = газа E хзам ALISN30- 553013118 SINE OF FIBRILLAR ANGLE Axial tension stiffness-density index (modulus of elasticity ~ specific gravity) correlated with sine of average fibrillar angle in summerwood for green specimens. Fig. 11. [Vor. 26 These of +.970, t = 12.618. т, , ANNALS OF THE MISSOURI BOTANICAL GARDEN weight. As a check on the validity of using only summerwood, twenty measurements each were made in the springwood of twelve tension specimens representing the complete range of angular variation. Averages of fibrillar angles were then cal- this relationship for southern yellow pine). weighted averages were correlated with those for summerwood culated with weighting based on area proportion and specific one for springwood, since Forsaith ('33) found approxi- gravity (constant weighting of three for summerwood and only, resulting in a correlation coefficient 56 mately s НЫНЫҢ LETETT авааввяв ЕРЕЕЕЕНЕЕН green specimens. strength + specific pecific gravity) cor- 1 + | ral та, LE CM Н d | - H t ODIU аны A E | 1 - _ TE Н T SINE OF FIBRILLAR ANGLE Fig. 12. Axial compression strength-density index (ultimate gravity) and stiffness-density index (modulus of elasticity + s 42 а пи 15 related with sine of average fibrillar angle іп summerwood for = X30N! ALISNIO-SSINISILS ХХІМІ A LISN3Q-H]9N3U1S 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 57 The average fibrillar angles of summerwood are given in column 11 of tables rr to v, along with their sines. Graphical eorrelation of the sines with strength- and stiffness-density indexes for axial tension and axial compression in green and air-dry wood is shown in figs. 10 to 15. The product-moment regression line is superimposed on each chart. A summary of the product moment correlation coefficients and their reliabili- ties is given in table vr. АП of the correlation coefficients are significant under the ; test except that for dry tension strength- density, for which the probability of r being unrepr tative is slightly greater than 0.1. Unfortunately many of the Tm ШЕШ БЕ HI ЕБ ГЕО E : us FTH m | КЕК STRENGTH -DENSITY INDEX ELLLLEI a R динг”! % виш але 5 Fs SÍNE OF FIBRILLAR ANGLE Fig. 13. Axial tension strength-density index (ultimate strength — specific ET А with sine of average fibrillar angle in summerwood for air-dry speci [Vor. 26 58 ANNALS OF THE MISSOURI BOTANICAL GARDEN stronger specimens in this series failed to break in the test section and could not be used as reliable. Тһеге appears to be little doubt but that the angle of fibrillar orientation or some factor closely associated with it is effective in determining the resistance of the wood to axial stresses. Whether the relationship in all series actually conforms to a mmi LI us К: иш: ШЕЕ ЕНЕ 1: = ETE pi Fi НО ПЕ LI M 5000 БЕЗІНІҢ ЕН ч ЕНШІ ЕЕ EFH nnn 55% EIER LL | cM erm ЧЧ ЕШ saa ЕНІН : NS H1 HH 55 БЕН ЕН FH ша! É ___ Е a | EH 21222222 | HET ii == UR OT HH ЕНІН НЕНА M C 5 STIFFNESS-DENSITY INDEX 45 SINE OF FIBRILLAR ANGLE Axial tension stiffness-density index (modulus of elasticity -- spec ecific gravity) correlated with sine of average fibrillar angle in summerwood for air- dry spec J ut RP о age A жалы 05 Үр, 0 <>. Ооо CEST т ра. о трг +N ! iE e, och e 70% s ie ЧАРА ТО WE UE T Т n TN к 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 59 straight line may not be determined by the amount and dis- tribution of the data at hand, though any curvilinearity in compression relationships would seem to be slight. 4000 - Š сирин STIFFNESS-DENSITY INDEX i Н - В 2 H Н nui HE EHE HH ШИШ HEHEH ER ШЕННЕ ii ЕН 2 ННННННН пун | Hu 2 10 uns | punc 5 ED z nanana E iu 7 | Е БЕЗ n SINE OF FIBRILLAR ANGLE Fig. 15. Axial compression strength-density index (ultimate strength ~ specific gravity) and stiffness-density index (modulus of elasticity ~ specific gravity) cor- related with sine of average fibrillar angle in summerwood for air-dry specimens. (Vor. 26 60 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE VI CORRELATION COEFFICIENTS OF RELATIONSHIPS OF STRENGTH- AND STIFFNESS-DENSITY INDEXES WITH AVERAGE ANGLE OF IBRILLAR ORIENTATION IN SUMMERWOOD Stress Index T t Green tension Stiffness-density —.832 7.192 reen i Strength-density -.837 5.723 Green compression Stiffness-density — 783 6.294 Green compression Strength-density —.574 3.505 Dry tension Stiffness-density —.834 7.404 Dry tension Strength-density —.384 1.664 Dry compression Stiffness-density -.873 10.438 Dry compression Strength-density -.710 5.879 At least we have here the only yet known measurable cri- terion of the strength of wood substance, and its control in the investigation of any other factor is indicated as necessary. The following observations on fibrillar orientation may be made from a study of the charts: (1) The effect on tension strength and stiffness is greater than upon compression strength and stiffness. (2) The effect on stiffness is greater than upon strength for both tension and compression. (3) Drying increases the effect upon compression strength and stiffness, i.e., drying increases the compression strength and stiffness more in the specimens of low angle than in those of high angle. (4) There appears to be more variability in specimens of low angle than in those of high angle. (5) Support is given to the view that the fibers of ‘‘com- pression wood’’ have a structure that is merely an extreme case of a condition that occurs in all conifer tracheids and that ‘‘abnormality’’ in the strength properties of wood substance is quantitative rather than qualitative. en the angular measurements were made, note was taken of the occurrence of checks in the central layer typical of ‘‘compression wood.’’ There was no evidence to show that checks were associated with a constant limit in fibrillar angle, nor that their presence explained the variation of any of the strength properties at any given fibrillar angle. Checks were 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 61 noted with angles as low as 15? but many fibers with angles as high as 28° were found to be unchecked. Generally tension specimens exhibited checks at a slightly lower fibrillar angle than compression specimens. Re-examination of growth rate as a factor showed that it is not responsible for the deviations still remaining in the correlation. The average ring width for specimens below the regression line is in none of the series significantly different from the average for specimens above the line. The plotting in these charts serves as reference in a search for the remaining factors controlling the resistance of wood to longitudinal stress. EXAMINATION OF TENSION FRACTURES OF THE WOOD The fractured portions of the tension specimens were sawn out and carefully preserved for examination under a 42.5 x (supplemented by 130 x) binocular microscope. Mounting the blocks on a universally movable holder enabled adjustment for the best possible light incidence on the fibers so that the rela- tion of fiber fracture to wood fracture could be studied. Generally brash failure for weak specimens and splintering for strong ones were noted. Green specimens splintered more than dry ones. Many strong dry specimens appeared to the eye to have brash failure but magnification showed the fracture to be composed of a large number of minute splinters of single fibers or small groups. Typical brash failure of weak wood exhibited the plane of fracture extending transversely across large groups of cells. Springwood portions were normally brash and summerwood splintered. Cell end fracture appeared mostly transverse in summer- wood fibers of strong pieces and frayed or spirally torn in those of weak ones. Springwood fiber end fracture was ir- regular, mostly with its general plane coinciding with the plane of failure of the wood. Commonly fiber fracture was observed to coincide with edges of wood rays in summerwood, the cells being broken off in radial rows. This ray association was less regular in spring- wood. Very strong summerwood fibers fractured independ- [Vor. 26 62 ANNALS OF THE MISSOURI BOTANICAL GARDEN ently, and the point of fracture of very weak ones was deter- mined by the general plane of fracture of the wood (brash fracture). Some summerwood fibers not fractured but with intaet ends projecting were commonly found at the fracture of very strong dry specimens. In the green series a few of these fibers were usually found even in the weakest specimens. Longitudinal cleavage of the wood (согоПагу to splinter- ing) was most profuse in strong and green specimens. Gross tangential longitudinal eleavage was not confined to either type of tissue, and often the cleavage plane was observed to extend aeross the border between springwood and summer- wood without interruption. Commonly the lateral fracture occurred through the cell in springwood and apparently be- tween fibers in summerwood. Exceptions to this rule were observed in the occasional occurrence of torn summerwood lateral walls in weak dry specimens and the frequent untorn springwood lateral walls of strong green specimens. Where the walls appeared untorn in lateral separation, fragments of the outer layer of the secondary wall were frequently seen clinging to the cells. On flat planes there were areas where longitudinal plates of the outer layer (with middle lamella and primary walls between) had been pulled laterally from be- tween the fibers on the opposite face of the plane. It was also frequently observed that the outer layer had been pulled from the central layer in transverse strips (according to the orien- tation of the cellulose in the outer layer). This separation of fibers at the interface between outer and central layer of the secondary wall was confirmed in the study of macerated fibers (pl. 3, figs. 1 and 3). The implication from the more frequent occurrence of un- fractured cells (central layer) in the green condition is that drying tightens the bond between outer and central layer, in- ereasing the strain on the central layer and causing cell frac- ture rather than cell separation. No constant criteria were derived from this study for the explanation of differences in strength between specimens of the same average angle of fibrillar orientation, though some 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 63 of the stronger specimens in the high-angle range exhibited the strong type of fracture (splinter) and some of the weaker specimens in the low-angle range tended to exhibit the weak type of fraeture (brash). Weak green tension specimens 9-C-4 and 9-A-3 (figs. 4 and 5) did not have brash summerwood frac- tures and had some unfractured fibers projected at the wood fracture. Strong dry tension specimens 5-D-3 and 5-D-4 (figs. 7 and 8) were brash. MICROSCOPIC EXAMINATION OF FIBERS For studying the relation of failure to fiber structure a method of microscopic preparation was sought which would give most clearly the actual pieture of conditions at the time of fracture. Isolation of fibers, under a dissecting microscope, with the aid of chemical maceration was chosen for this end. Short splinters were carefully split from fractured areas, boiled for several minutes (being held in water with a wire clamp), and treated with Jeffrey’s macerating fluid (equal parts of 10 per cent chromic acid and 10 per cent nitric acid) until several radial layers of fibers were loose enough to be removed by means of chisel-pointed needles. These radial groups and some single fibers, after washing, were lifted on a needle from the water by surface tension and mounted on a microscope slide in glycerine jelly. No stain was used since it might have clouded the structural features that were deemed important in this study. A polarizing microscope was used to identify structural detail and to accentuate fracture planes. Tension fiber fracture.—Springwood tracheids had frac- tured in no definable pattern (pl. 4, fig. 6), just as was noted in the low-power examination. The fracture often resembled that of a glass tube or, in the case of thicker walled-cells, the plane of fracture occasionally followed the fibril slope on one side of the cell and gave an irregular saw-toothed edge on the other. Ordinarily the fracture line avoided bordered pits but some- times passed around the border. Infrequently the wall was torn at a pit, revealing an annular dise of outer layer which was shown from dissection and from birefringent properties [Vor. 26 64 ANNALS OF THE MISSOURI BOTANICAL GARDEN to have concentric fibrillar structure. In some springwood tracheids where fibrillar striations were apparent the lines were seen to fade out over the pit chamber, suggesting an es- pecially closely knit structure of the central layer. Summerwood fibers of steep fibrillar orientation typically had transverse fracture (pl. 3, figs. 1 and 3). The fracture within the central layer often had a ‘‘pipe-organ’’ pattern, 1.e., fibrils or blocks of fibrils projected at uneven distances indi- eating both concentric and radial cleavage. In some steep- fibrilled specimens of relatively low strength (5-D-3 and 5-D-4) transverse cell fracture commonly sloped across the wall con- forming to the slip lines seen in compression failure. Summer- wood fibers of high fibrillar angle were commonly fractured along the fibril spiral with secondary planes at irregular angles (pl. 4, fig. 5), but some stronger specimens in this group (pl. 3, fig. 4), as well as those of medium fibrillar angle, ex- hibited various combinations of spiral and transverse fracture. In this medium fibrillar angle range there was some evidence that the stronger specimens exhibit transverse and ‘‘pipe- organ’’ fiber fracture (pl. 4, fig. 4). In those cases mentioned in the previous section where summerwood fibers were not broken in the tension fracture of the wood but were slipped apart longitudinally, the plane of fracture was located between the outer and central layers rather than at the middle lamella. Figure 1 of pl. 4 shows some of these apparently unbroken fiber ends from which the outer layer has been slipped. A remnant of outer layer can be seen on the second fiber from the right. Figures 2 and 3 of pl. 4 show a complementary condition where the outer layers which have been pulled off are clinging to whole fiber ends. Figure 3 identifies the outer layer by its weak birefringence. Lateral separation of fibers at the interface between outer and central layer is demonstrated similarly in pl. 3, figs. 1, 2, and 3. Compression test fiber fracture—Compression failure in springwood tracheids appeared as transverse undulating wrinkles in the double walls of adjacent cells without separa- 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 65 tion of the cells except at the region of gross fracture. With favorable position of the tracheids in the mount, slip lines were visible at the wrinkles. Some slip lines appeared in summer- wood fibers in areas away from the gross fracture with no ap- parent distortion of the cell wall. At the region of gross frac- ture the fibers were usually bent in a reverse curve yielding to the diagonal shear plane in the wood, and they were separated at their radial sides. Often these bands appeared to be ас- centuations of natural bends in the wall at ray crossings (pl. 5, fig. 4) but this was not general. Slip lines were concentrated at the bends. There appears to be little doubt but that slip lines are actu- ally planes of shear in the central wall. Frequently an offset in the entire wall was seen to be associated with a slip line (pl. 5, fig. 4, upper right, and pl. 6, figs. 1 and 3, lower center). Sometimes bulges on the inner side of a wall were subtended by a pair of slip lines (pl. 5, figs. 1 and 2, upper right). Slip lines were less numerous and less prominent in the fractures of fibers of high fibrillar angle (pl. 6, figs. 5 and 6, pl. 7, fig. 4) where most of the displacement appeared to occur along fibril- lar angle planes. The angle of slip lines with reference to fiber axis had been given in the literature as about 70 degrees. This was observed in the present study to be a good figure for summerwood of ‘‘normal’’ wood, but aside from considerable variations in a single fiber there appeared to be variations in average angle between specimens. Table үп gives some examples of average slip line angles based on small samples. TABLE VII AVERAGE ANGLE (AND RANGE) OF SLIP LINES REFERRED ТО THE — кшк" an OF THE CELLS FOR COMPRESSION TESTS N GREEN CONDITION (DEGREES) Low fibrillar angle High fibrillar angle 4-C-1 2-D-2 9-A-4 7-B-4 Summerwood | (70) 72 (76)| (69) 72 (76)| (52) 58 (61)| (66) 68 (72) Springwood | (52) 57 (62)| (48) 58 (63)| (40) 48 (60)| (41) 49 (59) [Vor. 26 66 ANNALS OF THE MISSOURI BOTANICAL GARDEN As in tension fracture, separation of the cells generally takes place at the interface between outer and central layer, with the middle lamella, primary walls and outer layers clinging to one of two separating cells. Plate 5, figs. 1 and 2, and pl. 6, figs. 1, 2 and 3 show remnants of outer layers that have been detached from adjacent cells. Plate 5, figs. 3 and 4, and pl. 6, fig. 4 show clearly the cleavage between central and outer layer. Because even the brief macerating treatment used here has caused some cell separation at the middle lamella it cannot be definitely stated that there is no mechanical cleavage at this plane. How- ever, the evidence of mechanical cleavage between the layers of the secondary wall was so extensive as to give the impression that this point is normally the center of mechanieal weakness between fibers. In fibers of high fibrillar angle lateral fracture was some- times not between the outer and central layer but within the central layer (pl. 7, figs. 1, 2 and 3). The central layer seems to be torn along fibrillar angle planes and in planes correspond- ing to slip lines. А structural character not previously emphasized in descrip- tions of **compression wood’’ but found quite constant in speci- mens of high fibrillar angle is the thickness of the outer layer of the secondary wall. This outer layer was found to be relatively thiek in summerwood fibers for these typically weak speci- mens. In fibers of medium and low fibrillar angle it varied con- siderably, and there was some evidence to indicate that thicker outer layers are associated with wood of low strength in its fibrillar angle class. Figure 1 of pl. 8 shows a macerated fiber from dry tension specimen 1-C-3, a weak specimen of medium fibrillar angle. The outer layer can be plainly identified and appears in best focus on the upper wall at lower right. Figure 2 is the same view under polarized light, with the fiber at the position of maximum brightness. Here the outer layer is not visible since its fibrillar structure at the cell edges is parallel with the light axis. The reduction in apparent diameter of the fiber is par- tially accounted for by the thickness of the outer layer. The 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 67 magnification of the polarized-light pietures was reduced about 10 per cent by insertion of the analyzer. Figs. 3 and 4 are com- parable views of a fiber from dry tension specimen 8-A-1, which has about the same average fibrillar angle as 1-C-3 but is much stronger. The two fibers have about the same total diameters in ordinary light but difference in outer layer thickness is shown by the difference in diameters under polarized light. Specimen 1-C-3 is typical ‘‘compression ооа”? material, and the checks in the central layer which are visible may ac- count for its strength deficiency as compared with specimen 8-A-1 in which checks were not found. Angle of fibrillar orien- tation, thickness of outer layer, and occurrence of fibrillar checks evidently vary independently. With the interface between outer and central layer being definitely involved in separation of cells it might be questioned whether the fibrillar slope of the outer layer is important to strength. Very few fibers were found whose fibrillar orienta- tion was not nearly transverse, and these were not confined to specimens of high or low strength. The occurrence of slip lines appears to be an important in- fluence upon tension strength. They were detected only in specimens which were weak for their fibrillar angles. Figures 9 and 6 of pl. 8 show a fiber from dry tension specimen 5-D-4 of low fibrillar angle and relatively low strength and stiffness in which typical compression slip lines can be faintly seen in the lower wall. End fracture of many fibers in this specimen conformed to these planes. V. Discussion The types of variations that may influence the axial strength properties of wood substance (strength of wood with density eliminated) may be enumerated as follows: A. Architectural 1. Growth rate 2. Proportion of summerwood and springwood based on specific gravity [Vor. 26 68 ANNALS OF THE MISSOURI BOTANICAL GARDEN 3. Tissue variation 4. Cell morphology я . Constitutional 1. Cell-wall structure 2. Structure of the central layer 3. Distribution of constituents of the wood substance 4. Chemistry of constituents This study has been concerned mainly with methods of frac- ture of a wood of simple anatomy with the aim of identifying the more important of the above variations. As a starting point the characteristics of ‘‘compression wood’’ have afforded clues for the solution of the problem, though no assumption has been made as to the relative importance of such characteristics or as to the interdependence of their variability. Growth rate has long been associated with weakness in wood, and it still may be a good criterion for absolute strength. However, there is little indication that growth rate in itself has much influence upon the strength of wood substance. Figures 4 to 9 show that in both tension and compression many fast-grown specimens are strong for their density, and ‘‘abnormal’’ material is not excluded from narrower rings. Further, growth rate does not appear in this study to be associ- ated with variations in the strength aside from those dependent upon the character of the cell wall (fibrillar angle). Percentage of summerwood is an artificial criterion of ab- solute strength but has not been used in this study. It is recog- nized that the proportion of summerwood to springwood on the basis of solid volume may be important since it would reflect the relationship between average cell diameter and average cell-wall thickness in the two types of tissue. In the wood under consideration histological variations ap- pear to be minimized since one tissue preponderates. The vari- ation in area of wood rays and resin ducts has been found by Berkley (734) to be slight with reference to total sectional area and slight in average percentage between his strongest and weakest compression specimens ‘‘per unit weight.’’ It 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 69 does not seem that the amount of ray tissue and area occupied by resin canals have considerable effect in determining axial strength properties though a variation in the number of rays may be important since they influence the morphology of tracheids. Variations in the form of tracheids entail chiefly length, sectional shape and indentations caused by adjacent wood rays, and the occurrence of bordered pits. Since generally fiber frac- ture occurs in both tension and compression on transverse planes it is not thought that tracheid length is very important. It may influence the tensile strength of specimens in which many fibers are pulled apart longitudinally without fracture of the central layer. In these cases longitudinal shear is in- volved and the average shear area is less for shorter fibers. Berkley’s (’34) outlying compression specimens were not sig- nificantly different in fiber length. Variation of sectional shape from rectangular to circular, though it constitutes one difference between ‘‘normal’’ wood and ‘‘compression wood,’’ has not been investigated. Mechani- eally the advantage in this respect for compression strength would seem to be on the side of the more cylindrical fibers of ‘‘compression wood.’’ The curves in tracheid walls at the edges of wood rays have often been seen in this study as points of fracture in both ten- sion and compression though this is more general in tension fracture than in compression. Correlation of tensile strength with number of rays per unit area may be worthy of investiga- tion since this is known to vary considerably within a tree. Bordered pits have been proposed as sources of weakness in cell walls, but they rather seem to be in themselves sources of strength in tension. The possibility remains that a pre- ponderance of bordered pits causes weakness because of the deviation of the fibrils of the central layer around them. The detailed work recently published by Dr. I. W. Bailey and his associates on the constitution of the tracheid wall pro- vides a basis for interpretation of mechanics of the failure of wood substance. The true middle lamella is a very thin [Vor. 26 70 ANNALS OF THE MISSOURI BOTANICAL GARDEN layer of isotropic material separating the cells. This binding material has been mentioned as having influence upon strength but it has been shown in this study as less apt to be a plane of weakness than structural planes within the wall itself. Actu- ally under axial loads separation of cells is usually only inci- dental to yield within the cell wall. Under compression loads cells separate only when the walls have already failed in diagonal shear. In longitudinal tension, separation appears to be caused by lateral tension between cells resulting from lateral compression within a cell or group of cells, a component of the longitudinal tension force. Evidence of this is seen in the manner of fracture of sheets of double outer layers that obviously have been pulled laterally from between cells (pl. 3, fig. 3). In those cases where the central layer is not fractured in axial tension (pl. 4, fig. 1), failure occurs from longitudinal shear between outer and central layer. The lateral fracture within the central layer (pl. 7, figs. 1, 2 and 3) is interesting in view of findings of Bailey and Kerr (737), that the two layers of the secondary wall in **Rotholz"' tracheids are separated by “ат isotropic layer of non-cellulosic composition." It would appear that the isotropie material is stronger in tension than is the cellulose structure perpendicular to its orientation plane. The primary wall has not been identified with mechanical failure, and it is probable that it is so closely associated with the amorphous material of the middle lamella that it does not act independently. Wide variation in the thickness of the outer layer of the secondary wall in summerwood leads to the conclusion that this may be an important measurable criterion for axial strength. The fibrils here approach transverse orientation and are at least an advantage in resistance to longitudinal or local shear stresses. F'urther, the peripheral position of the layer causes slight deviations in thickness to be reflected in dispro- portionate changes in sectional area of the cell wall. As an example, measurements from pl. 8, figs. 1 to 4 may be given. When diametrical measurements are made on the photographs (considering the difference in magnification between ordinary 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 71 and polarized light) and the circular areas of the layers com- puted, it is seen that the outer layer has 52 per cent of the total wall area in the fiber of 1-C-3 and only 26 per cent in the fiber of 8-A-1. The thicknesses of the outer layer indicated by this method of observation are 4.2 и and 2.4 y respectively. Be- eause the sections of the fibers are not circular as has been assumed in this example and because of the possibility of optieal error, this technique is not recommended for measur- ing the variable. However, justifieation for work on an ae- curate method of measurement in connection with strength studies is indicated. That the characteristics of the central layer of the secondary wall are the most important criterion of axial mechanical properties of wood substance is suggested by the fact that variations in stiffness dependent upon fibrillar angle are greater than the remaining variations (figs. 10 to 15). This evidence is not seen in the consideration of ultimate strength, and it might be assumed that different factors affect stiffness and strength. Tt is more probable that the greater variation in ultimate strength is caused by uneven distribution of stresses and consequent local failure precipitating the failure of the specimen. Thus modulus of elasticity is probably the best measure of average mechanical resistance. There appears to be some connection between the relation- ships of stiffness with fibrillar angle and what we now know of the structure of the cell wall and its method of fracture. Re- sistance in tension is about twice that in compression in fibers of steep angle. In this type of fiber, tension fracture has been shown to result from longitudinal strain on the elongated cellulose framework; the system is broken. Compression frac- ture in these fibers is a result of diagonal shear strain (along slip lines) across the concentric density laminae of the cellu- lose system. Actual rupture is not usually visible, and it is probable that there is involved only distortion, perhaps bend- ing of fibrils similar to that in gross fracture. Stiffness in tension is shown to be only slightly higher than that in compression in fibers of high fibrillar angle. Here both [Vor. 26 12 ANNALS OF THE MISSOURI BOTANICAL GARDEN tension and compression fracture are seen to result from shear strain between the fibrils or along the radio-helieal disconti- nuities in the cellulose framework shown by Bailey and Kerr (37) to occur in **eompression wood.’’ This is undoubtedly because the fibrillar angle approaches the theoretical 45? angle of shear which tends to operate under simple loading. An ad- ditional reason applicable to the compression mechanism is the radial density pattern in the central layer, providing re- sistance to shear across the wall. Further evidence that the mechanism of resistance for com- pression is different from that of tension is seen by an exami- nation of the effect of drying. Stiffness in tension is increased about the same amount throughout the range of fibrillar angle, which is only slightly less than the increase for compression stiffness at high fibrillar angles. At low angles for compres- sion stiffness the increase is approximately doubled. It seems a logical conclusion that shear across fibrils (slip lines) is more concerned with secondary valences than is inter-fibrillar shear. Since the transition from normal to ‘‘compression wood’? is a gradual one, changes in fibrillar angle are perhaps more or less accompanied by changes in other characters, and it may not be stated positively that the dependence shown in these charts is attributable solely to the measured variable. How- ever, this study indicates that some of the structural features of ‘‘compression ооа”? do not vary concurrently. Proportion of outer layer in the secondary wall and pattern of density variation in the central layer are two characters which are worthy of further investigation in a search for causes of varia- tion from the relationships of axial strength to fibrillar angle. Quantitative criteria for the latter feature might be found in the angle of slip lines and the frequency of central wall checks. It may be discovered that the change from concentric to radial density pattern is a positive influence on compression strength since it tends to inhibit the formation of slip lines. Koehler (’33) has stated that compression damage, sus- tained in the tree and indicated by slip lines, is a cause of brashness in tension. This seems to be confirmed in this study 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIO STRUCTURE 73 where slip lines are associated with relatively low tension strength (pl. 8, figs. 5 and 6). There is a possibility that tension strength is affected by this factor without detection, i.e., the damage may be so slight that slip lines are invisible with technique now available. SUMMARY The faetors necessary of consideration in a complete study of the strength properties of coniferous wood are reviewed with stress upon the structure of the tracheid wall. Four series of engineering strength tests are reported for earefully chosen specimens representing nine logs of com- mercial shortleaf pine wood; (1) axial tensile strength, green wood, (2) axial tensile strength, air-dry wood, (3) axial com- pression strength, green wood, (4) axial compression strength, air-dry wood. Ultimate strength and modulus of elasticity are given for each test. The factor, specific gravity, is eliminated from the comparisons of specimens by expressing mechanical properties as ‘‘strength-density index’’ (ultimate strength -- specific gravity), and ‘‘stiffness-density index’’ (modulus of elasticity -- specific gravity). These indexes are plotted over growth rate, showing that this is not a universal criterion of mechanical properties of wood substance, though it controls the frequency of occurrence of weak specimens. The indexes are correlated with the sine of the average angle of fibrillar orientation in summerwood, resulting in significant product-moment correlation coefficients in all cases except one in which the distribution of the data is obviously inadequate. Variations from the regression lines are not connected with growth rate. Examination of tension fractures under low-power binocular microscope revealed the following: (1) The typical brash gross failure observed for strong dry wood is not of the same cellular detail as that exhibited by weak specimens. [Vor. 26 74 ANNALS OF THE MISSOURI BOTANICAL GARDEN (2) Fracture of springwood cells is determined generally by the plane of shear stress for the wood. (3) At longitudinal cleavage planes in summerwood, frag- ments of outer layer are seen clinging to apparently whole cells, indicating that cell separation may occur between outer and central layers of the secondary wall rather than at the middle lamella. Longitudinal cleavage in springwood is fracture through the cells. (4) End fracture of radial rows of tracheids often occurs at the intersection of these cells with one edge of a wood ray. (5) Some fibers, unfractured in tension, are seen in strong dry specimens and more widely distributed in the green series. (6) There is some evidence that brash failure is associated with relatively low strength among specimens of steep fibrillar angle and that splintering occurs with relatively high strength at high fibrillar angles. The principal observations in microscopic examination of isolated fibers of tension specimens are as follows: (1) Bordered pits are not sources of weakness. (2) Concentric arrangement of fibrils in the outer layer of the secondary wall at bordered pits is confirmed. (3) Springwood cells generally fracture in no definable pat- tern. (4) Fibers of steep fibrillar orientation have transverse fracture with some independent fracture of groups of fibrils; some of the weaker specimens have fiber fracture conforming to typical compression slip lines. (5) Summerwood fibers of high fibrillar angle fail mostly along fibrillar planes with some secondary planes of irregular angle. (6) Medium fibrillar angles are associated with various combinations of transverse and spiral fracture, with stronger fibers favoring the transverse type. (7) Lateral separation of fibers is seen to occur mostly, if not always, at the interface between outer and central layers of the secondary wall. 1939] GARLAND— WOOD STRENGTH AND MICROSCOPIC STRUCTURE 75 (8) Where fibers are not fractured in tension, failure is indieated as longitudinal shear between outer and central layer. The following observations concern fibers in compression specimens: (1) Slip lines are confirmed as planes of shear on the cell wall. (2) Fracture of fibers of steep fibril angle is seen as bending in the cell wall where slip lines are concentrated. (3) Fiber fracture at high fibrillar angles follows fibrillar planes. (4) Cell separation is normally between outer and central layers of the secondary wall. (5) Cell separation in summerwood fibers of high fibrillar angle may occur within the central layer. (6) There is some evidence that slip line angles are greater in material of low fibrillar angle. Wide variation is shown to occur in thickness of outer layer, with greater thickness mostly associated with greater fibrillar angle. The relative importance of the factors that may affect the axial strength properties of wood is discussed, and it is con- cluded that the factors most likely connected with variations remaining after control of specifie gravity, moisture, and fibrillar angle are: (1) Proportion of springwood and summerwood by weight. (2) Proportion of outer layer to central layer of the sec- ondary wall by sectional area. (3) For eompression strength—variation of angle of slip lines and frequency of fibrillar checks. (4) For tension strength—number of wood rays per unit of tangential area. (5) For tension strength—the degree of compression dam- age previously sustained as seen by the occurrence of slip lines. [Vor. 26 16 ANNALS OF THE MISSOURI BOTANICAL GARDEN ACKNOWLEDGMENTS The writer wishes to acknowledge gratefully the uncondi- tional support of the American Creosoting Company in main- taining the fellowship under which this work was pursued. The excellent library facilities of the Missouri Botanical Garden, made available by Dr. George T. Moore, Director, have proven invaluable. Professor A. W. Brust, of the Department of Civil Engineering, Washington University, and Dr. E. S. Reynolds, Physiologist in the Henry Shaw School of Botany, have over- seen the engineering and botanical phases of the work. Тһе cooperation of Mr. Joseph W. Graves, Jr., American Creosot- ing Fellow in Civil Engineering, in gathering and assembling the engineering data is appreciated. BIBLIOGRAPHY oo J. B. (735). The effect of 5” ү growth upon the ин к and th of Douglas fir. Canada Dept. Int., For. Serv. Cire. 44: 8 pp. 2 figs. лм КУ." for Testing Materals i^m Standard methods of testing small of timber. A.S.T.M. Designation D143-27, Am. Soc. Test. Mat., А.8.Т.М. кайа, pt. II, Nonmetallie Materials, pp. 408-444. Astbury, W. T. (733). Some сың in the X-ray analysis of the structure of ani- mal hairs and other protein fibers. Faraday Soc., Trans. 29: 193-211. Bailey, I. W. (738). Cell wall uf of Ми plants. Ind. and Eng. Chem. (Ind. Ed.) 30: 40—47. 27 figs. , and T. Kerr (735). The visible structure of the secondary wall and its significance in physical and chemical investigations of tracheary cells and fibers. Jour. Arnold Arbor. 16: 273—300. 10 p ‚ (737). The Коа. variability of the secondary wall as ы by (* lignin’? residues. Ibid. 18: 261-272. 4 pls , and Mary R. Vestal (737). Тһе orientation of сіне in the conda. v wall of tracheary cells. id. 18: . 8 pls. Berkley. Е. E. (934). Certain physical and structural Ыр иш of three species of etd yellow pine eorrelated with the compression strength of their wood. nn. Mo. Bot. Gard. 21: 241-338. 5 pls. 15 figs Bienfait, J. РА (726). Relation of the manner of jets to the structure of wood under compression parallel to the grain, Jour. Agr. Res. 33: 183-194. 6 figs. Brust, A. W., and E. E. Berkley (’35). The distribution and variations of certain strength and elastic olan of clear southern yellow pine wood. Am. Soc. . Mat., Proc. 35*: 1-31. 19 figs Ира. r^ a E. Mone ome The M and life of forest trees. English айран by Thomas Thomson. 436 pp. 173 figs. New York 1939] GARLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 77 Clarke, S. H. (733). On ripae the Voce strength of the wood of ash Frazinus excelsior L.). stry 7: 26-31. . 2 figs. , (736). The + Al of cell-wall E on the pm prop- erties of “Кет wood (Fagus sylvatica L.). Ibid. 10: 143-148, 1 pl. 1 Dadswell, Н. E., and L. Е. Hawley (729). Chemical composition of wood % rela- oon to physical characteristics—a preliminary study. Ind. and Eng. Chem. 73-975. Du P Ais ко of wood substance and porosity of wood. Jour. Agr. Res Fora ths z Pu p The technology of New York State timbers. N. Y. State Coll. For., Tech. Publ. 18: 374 pp. 130 figs 938). The Оор конне of small beams (match stick size) of southern yellow pine. Ibid. pp. 8 figs. Prey elg A. (735). Die Piedad der hóheren Pflanzen. 378 рр. 9 figs. Berlin. Hartig, В. (1885). Das Holz der deutschen Nadelwaldbüume. 147 pp. 6 figs. Berlin. » (701). Holzuntersuehungen: altes und neues. 99 pp. 52 figs. Berlin. Houwink, В. (737). Elasticity, plasticity and structure of matter. 376 рр. 213 figs. Iwanoff, L. A. (733). Wie sieh die Struktur des Holzes bei EEG Ein- wirkung ändert. (German summary). Jour. Bot. U.R.S.S. ies —51. Jaccard, P. (710). Etude e p us de bois comprimés. Већу Tore nst. Forst. Versuchsw., Mitt. 10: 57. (Paper not seen; cited Dd Bienfa it, 726.) Jalava, M. (734). Stre e properties of Finnish pine (Pinus silvestris). II. Air-dry testing material. [Summary in English]. Comm. Inst. For. Fenniae 19% 12-13 Kerr, T., and I. W. Bailey (734). The cambium and its derivative tissues. No. X. Structure, optical properties and chemical = of the so-ealled middle lamella. Jour. Arnold Arbor. 15: 327—349. Koehler, A. (733). Causes of brashness in wood. M S. Dept. Agr., Tech. Bull. 342: pp. 22 figs. — — — ——, (238). Rapid growth hazards usefulness of southern pine. Jour. For. 36: 153- 158. 4 figs Kollmann, Е. (36). Теш des Holzes. 764 pp. 1 pl. 604 figs. Berlin. ess I. (731). Untersuchungen über den Einfluss des Waldtyps auf die Qualität т Kiefer. Acta Forest. Fenn. 37:: 1-128. 40 figs. тий, M. (731). Untersuehungen über Aufbau und Bildung der pflanzlichen Zellmembran und ihrer stofflichen Komponenten. Biochem. Zeitschr. 233: 57. 8 figs. Luxford, В. Е. (7/31). Effect of extractives on the strength of wood. Jour. Agr. Res. 01-826. Maby, J. C. (736). Micellar structure of the tracheide wall in certain woods relation to morphogenetic and mechanical factors. New Phytologist 35: 432- 455. 2 pls. Markwardt, L. J., and T. R. C. Wilson (735). Strength and related pe of woods grown in the United States. U. S. Dept. Agr., Tech. Bull. 99 pp. [Vor. 26 78 ANNALS OF THE MISSOURI BOTANICAL GARDEN Meyer, K. H. (728). Neue Wege in der ее y ang und in der Erforschung hochpolymerer verbindungen. Nat . 16: 781-793. Norman, A. G. (737). The biochemistry of disse $ de айде, lignin, ete. 232 pp. 13 figs. Oxford University. Paul, В. Н. (730). The application of vico in gi ee the specifie gravity of wood. U. S. Dept. Agr., Tech. Bull. 168: ; i Pillow, M. Y., and R. F. Luxford (737). riii occurrence, set properties of compression wood. U. 8. Dept. Agr., Tech. Bull. 546: 32 pp. 9 pls. 8 figs. Preston, В. D. (’34). The рана." of the cell wall of the conifer tracheid. Roy. Soe. London, rege s. B. 224: 131-174. Record, P 7, et al. (733). ssary of terms used in describing woods. By Com- mittee on Nomenelature 22 Association of Wood Anatomists. Тторі- eal Woods 36: 1-12. Ritter, G. J. (735). The morphology of cellulose fibers as related to = manufacture of paper. Paper irr Jour. 101: (TAPPI Sect. 264-272. 28 figs.). ————————, and . Chidester (728). Тһе mierostrueture 5 а wood-pulp fiber. Ibid. p^ Pee бесі. 159-165. 49 pls. 1 fig. , and L. C. Кіеек (726). Chemistry of wood. {ЖИ ЕР ала erwood. Jour. Ind. Chem. 18: 608—609. Robinson, W. (720). The microscopical features of mechanical strains in timber the bearing of these on the structure of the cell wall in plants. Roy. Soc. в Phil. Tran ans. B. 210: 49-82, Rothe, G. (730). "Rn mes und Se rarer des Rot- und Weissholzes der Fichte. Tharandter Forstl. Jahrb. 81: 204-231. Russell, J. K., O. Maas s, and W. Boyd ешле (737). Sorption of water and aleohol vapors by cellulose. Can. Jour. Res. 15»: 13-37. Scarth, G. W., В. D. Gibbs, and J. D. Spier (29). Studies of the cell walls in wood. I. The owe of the cell wall and the local distribution of the chemical con- stituents. Roy. Soc. Canada, Trans. III. 23: Sect. -279. Schellenberg, H. (1896). Beitrüge zur Kenntniss der ићи Zellmembran. ahrb. f. wiss. Bot. 29: 237-266. von — Н. (728). Mechanical wear of ties. Am. Rail. Eng. Assoc., Bull. *: 180 pp. 178 figs. Seifriz, W., and C. W. Hock. (736). The structure of paper pulp fibers. Paper Trade Зехнй 102°, (ТАРРІ Sect. 250-252. 2 figs.). Sonntag, Р. (708). Ueber die mechanischen Eigenschaften des Roth- und Weiss- holzes der Fichte und anderer Nadelhólzer. Jahrb. иј wiss. Bot. 39: 71–105. — (09). Die duktilen Pflanzenfasern, der ihrer 2 еп Zellen "^ die etwaigen Ursachen der Duktilitát. a 99: 203-259. 8 figs. Stamm, A. J. (729). Density of wood substance, adsorption by wood, ia perme- ability of wood. Jour. . Chem. 33: 398—414. я CN Colloid есіні of eellulosie materials. Т), S. Dept. Agr., c. Publ. 240: 90 pp. жәй E.» С" 06). Effect of moisture upon the gre uta and stiffness of wood. . S. Dept. Agr., For. Serv. Bull. 70: 144 pp. 4 pls. 25 figs 1939] GABLAND—WOOD STRENGTH AND MICROSCOPIC STRUCTURE 79 pr В. (731). Festigkeitsuntersuchungen an Douglasienholz. Mitt. f. twirtshaft u. Forstwissenshaft. 2: 13 932). Ueber die р des Rot- oder Druckholzes der Nadelhülser. Allg. Forst- und Jagd-Zeit. 108: 1-14. 4 figs. Turner, L. M. (35). Key to the trees of i5 ad in late summer and fall. Univ. Ark. Dept. Hort. and For. Mimeographed pamphlet. 45 pp. ; (737). Growth of second- n pine on the coastal plain soils of АБИР: Ark. Agr. Exp. Sta. Bull. 342: 52 Ursprung, А, (706); Untersuchungen 154 m Fostigkeiteverhiliniee an exzen- is Wilson, T. R. C. ( 52. Strong moisture relations for wood. U. S. Dept. Agr., Tech. Bull. 282: 88 pp. 44 fig ; (734). Guide ін the grading of structural timbers and the determina- tion of жы stresses. U. S. Dept. Agr., Misc. Publ. 185: 26 pp. Winslow, C. P. (733). Enlarging the consumption of forest produets. A national plan for American forestry. 730 Congress, lst Session, Senate Document, 12: 1355-1394. и [Vor. 26, 1939] 80 ANNALS OF THE MISSOURI BOTANICAL GARDEN ExPLANATION оғ PLATE PLATE 1 Fig. 1. Drill press with shaper arranged for finishing test sections of tension specimens. Fig. 2. Tension specimen in Amsler hydraulic testing machine with extensom- eter in place. [Note. An error has been made in labeling all of the accompanying plates Volume 27 instead of Volume 26.] PLATE 1 ANN. Мо. Вот. Garp., Vor. 27, 1939 GARLAND —WOOD STRENGTH AND MICROSCOPIC STRUCTURE [Vor. 26, 1939] 82 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION оғ PLATE PLATE 2 Cross-section from the middle of the 215-inch planks used for testing, with posi- tions of specimens indieated. ANN. Мо. Bor. Garp., Vor. 27, 1939 PLATE 2 Que PLU PLN | Mr ШІ | W 7 i} ; Ж ИИ TM H a WZ ^ = E | TN GARLAND —WOOD STRENGTH AND MICROSCOPIC STRUCTURE [Vor. 26, 1939] 84 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 3 Fig. 1. Radial group of summerwood tracheids from green tension specimen 8-C-4, showing typical transverse and ‘‘pipe-organ’’ fracture of strong fibers. Note sleeves of outer layer projecting. Fig. 2. Same as fig. 1 with е: inserted. x 396. Fig. 3. Summerwood tracheid from green tension specimen 2-C-2, showing typieal end fracture of strong fibers and fracture of outer layer due to lateral sepa- ration, x Fig. 4. Radial group of summerwood tracheids from dry tension specimen 2-A-6, showing eombination of spiral eleavage and transverse fracture. This вресі- men is relatively strong for its high fibrillar angle (sine, .550). x 4 ANN. Мо. Bor. Garb., Vor. 27, 1939 PLATE 3 GARLAND —WOOD STRENGTH AND MICROSCOPIC STRUCTURE [Vor. 26, 1939] 86 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 4 Fig. 1. Radial group of summerwood tracheids from green tension specimen 9-C-1 at fracture, showing fiber ends whole, common in strong specimens. It is evident ep: these tips consist of a incidid layer from which the outer layer has been Fig. + Radial group of summerwood tracheids from green tension specimen B-2, showing method of fracture common for strong fibers. The central layers of the secondary wall are unbroken and separation has occurred between the central and outer layers. Note sleeves and sheets of outer layer projecting. x 100. Fig. 3. Same as fig. 2 with analyzer inserted. x 90. ig. 4. Radial group of summerwood tracheids from dry tension specimen 3-D-5, showing fracture of the ‘‘pipe-organ’’ type and separation along the fibrils. This specimen is of medium fibrillar angle (sine, .310) and is relatively strong. x 440. Fig. 5. Radial group of summerwood tracheids from green tension specimen 9-A-4, showing typieal spiral fraeture of fibers of high fibrillar angle (sine, .510). x 100. Fig. 6. Radial group of springwood tracheids from dry tension specimen 3-D-5, showing typical irregular fracture. x 100. ANN. Mo. Вот. Gard., Vor. 27, 1939 PLATE 4 GARLAND —WOOD STRENGTH AND MICROSCOPIC STRUCTURE [Vor. 26, 1939] 88 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 5 Fig. 1. Summerwood tracheid from dry compression specimen 4-A-1 at fracture, showing prominent slip lines and rupture of the outer layer. The fragment of outer layer above belongs to an adjacent cell and has been partially separated at the mid- dle lamella by maceration. x 440. Fig. 2. Same as fig. 1 with analyzer inserted. x 896 ig. чодра 0 traeheid from green compression specimen 2-D-2 аё frae- ture, rien slip line concentration typical of strong fibers and rupture between central and outer layers. x 440. Fig. 4. Tangential view of a radial group of summerwood tracheids from dry compression speeimen 2-B-2, showing prominent slip lines associated with displace- ments of wall material. The bend above is coincident with a ray crossing and the creases occur at the pits. x 440. ANN. Мо. Вот. Garp., Vor. 27, 1939 PLATE 5 GARLAND —WOOD STRENGTH AND MICROSCOPIC STRUCTURE [Уог. 26, 1939] 90 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 6 Fig. 1. Summerwood tracheid from dry compression specimen 4-A-1 at fracture, showing prominent slip lines associated with displacements (diagonal shear) in the walls and with movement of the wall material into the lumen. x 440. Fig. 2. Same as fig. 1 with focus on a sheet of outer layer at upper right show- ing it to be a remnant of an adjacent cell. x 440. Fig. 3. Same as fig. 1 with analyzer inserted. ig. 4. Summerwood tracheid from dry compression specimen 7-B-4 at fracture, ғ... slip lines and separation of outer layer from central layer. x 440. Fig. ummerwood tracheid from green compression specimen 9-A-4 at frac- ture, iu few slip lines and thick outer layer which is apparently not closely associated with the central layer. This is a typical ‘‘ compression wood" fiber with high fibrillar angle (sine, .490) and prominent checks in the central layer. x 440. Fig. 6. Same as fig. 5 with analyzer inserted. x 396, PLATE 6 Ann. Mo. Вот. Garp., Vor. 27, 1939 ND MICROSCOPIC STRUCTURE NGTH A 4 GARLAND—WOOD STR [Vor. 26, 1939] 92 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 7 Fig. 1. Radial group of summerwood tracheids from green compression speci- men 7-A-4 at fracture, showing method of separation that may occur between fibers of high fibril angle (sine, .450). Lateral rupture has occurred mostly within the central layer and has followed planes of slip lines and of fibril orientation. Focus on mar view at left. x 440. ig. e as fig. 1 with foeus on a single fiber that has become detached from ы group nde turned to present а tangential view. x 440. Fig. 3. Summerwood tracheid from green compression specimen 7-A-4 at frac ture, чйр. "i of the central layer of the secondary wall due to poet separation ig. 4. por group of summerwood tracheids from dry compression specimen 9-D-4 at fracture, showing thick outer layer and scarcity of slip lines typical of fibers with high fibrillar — I- .410). The fiber at the right has fractured along planes of the fibrillar 440. Fig. 5. Group of siti eur Анын from green tension specimen 7-A-4 of rather high fibrillar angle (sine, .390), showing thiek outer layer and absence of checks. This specimen is relatively low in strength. x 440. Fig. 6. Same as fig. 5 with analyzer inserted. PLATE 7 ANN. Mo. Вот. Garb., Vor. 27, 1939 RE GARLAND —WOOD STRENGTH AND MICROSCOPIC STRUCTU [Vor. 26, 1939] 94 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 8 Fig. 1. Summerwood tracheid from dry tension specimen 1-C-3 of medium fibril- lar angle (sine, .330), showing relatively thick outer layer and prominent checks in the central layer. This specimen is weak in eomparison with speeimen 8-A-1 (figs. 3 and 4). x 440. Fig. 2. Same as fig. 1 with analyzer inserted. x 396. Fig. 3. Summerwood traeheid from dry tension speeimen 8-A-1 of medium fibrillar angle (sine, .350) showing outer layer relatively thin and absence of checks. is specimen is Ane in comparison with speeimen 1-C-3. x 440. Fig. 4. S as fig. 3 with analyzer inserted. x 396 Fig. 5. „питао tracheid from dry tension speeimen 5-D-4 of low fibrillar angle (sine, .110) and relatively low strength showing slip lines which may have been present before the test. x 440. Fig. Same as fig. 5 with analyzer inserted. x 396. ANN. Мо. Вот. Garb., Vor. 27, 1939 PLATE 8 ^, mu ше; 6 GARLAND —WOOD STRENGTH AND MICROSCOPIC STRUCTURE Annals of the Missouri Botanical Garden Vol. 26 APRIL, 1939 No. 2 NEW OR OTHERWISE NOTEWORTHY APOCYNACEAE OF TROPICAL AMERICA. УГ ROBERT E. WOODSON, JR. Assistant Curator of the Herbariwm, Missouri Botanical Garden Assistant Professor in the Henry Shaw School of Botany of Washington University Mandevilla Lobbii Woodson, spec. nov., fruticosa volubilis; ramis sat gracilibus juventate dense minuteque puberulis tan- dem glabratis; foliis oppositis petiolatis ovato-elliptieis apice acute acuminatis basi rotundatis vel leviter cordatis 3.5-6.0 em. longis 1.8-2.7 cm. latis firmiter membranaceis supra sparse pilosulis nervo medio basi pauciglanduligero subtus puberulis ; petiolis 0.5-0.6 em. longis puberulis; appendicibus stipulaceis minutissimis vix bene visis; racemis simplicibus lateralibus flores gilvos (?) 4-7 gerentibus; pedunculo petiolos ca. ter su- perante dense puberulo; pedicellis са. 1 em. longis minute pu- berulis ; bracteis obovato-ellipticis acuminatis subfoliaceis 0.6— 1.0 em. longis minute puberulis persistentibus ; calycis laciniis lanceolatis acuminatis 0.6–0.7 ст. longis extus sparse pilosulis squamellis multis attenuatis; corollae salverformis extus gla- brae vel indistincte papillatae tubo 1.8 em. longo basi et apice ea. 0.17 em. diametro prope medium paulo inflato ibique stami- nigero, lobis late et oblique obovatis breviter acuminatis 1.5 em. longis patulis ; antheris 0.7 em. longis basi truncatis vel paululo rotundatis glabris; ovario ovoideo glabro ca. 0.2 cm. longo; stigmate umbraculiforme 0.4 em. longo longe аріспізіо; пес- 1 Issued April 29, 1939. ANN. Мо. Bor. бавр., Vol. 26, 1939. (95) [Vor. 26 96 ANNALS OF THE MISSOURI BOTANICAL GARDEN tariis 5 emarginatis ovario multo brevioribus; follieulis igno- tis.—PEnv : data incomplete, Lobb s.n. (Herb. Naturhist. Mus., Wien, TYPE). Closely allied to M. Jamesonii Woodson, but differing in the strikingly developed braets which recall several species of the subgen. Exothostemon. Mandevilla dissimilis Woodson, spec. nov., suffruticosa volu- bilis; ramulis teretibus juventate minute puberulis mox gla- bratis ; foliis oppositis petiolatis oblongo-elliptieis apice acute acuminatis basi cordatis 4—5 em. longis 1.8-2.5 em. latis firmiter membranaceis supra minute puberulis tandem glabratis nervo medio basi pauciglanduligero subtus dense puberulis ; petiolis 1.0-1.3 em. longis minute puberulis; appendicibus stipulaceis minutissimis; inflorescentiis racemosis simplicibus folia sub- aequantibus flores gilvos (?) 8-10 gerentibus; pedunculo petiolos subaequante minutissime puberulo; pedicellis 0.4—0.5 em. longis minutissime puberulis; bracteis attenuatis 0.3–0.4 em. longis; calycis laciniis lanceolatis acuminatis 0.6-0.7 cm. longis minute puberulis; corollae infundibuliformis extus omnino minute puberulae tubo proprio 0.6 em. longo basi ca. 0.15 em. diametro, faucibus campanulatis 0.65 em. longis, ostio ea. 0.45 em. diametro, lobis late et oblique obovatis 0.6 em. lon- gis patulis; antheris inclusis 0.4 ст. longis basi truncatis; ovariis ovoideis minute puberulo-papillatis са. 0.15 em. longis; neetariis ovarium ea. dimidio aequantibus truncatis vel leviter emarginatis; stigmate umbraculiforme 0.3 em. longo longe apieulato ; follieulis non visis.—Ecvapon: ‘‘ Andes Quitenses,’’ data incomplete, Spruce s.n. (Herb. Naturhist. Mus., Wien, TYPE). This species is closely allied to M. equatorialis Woodson, but appears to me sufficiently distinct for specific rank because of its considerably larger flowers with proportionally longer proper tube. The leaves, also, are broader, with a shorter petiole. Fernaldia asperoglottis Woodson, spec. nov., suffruticosa volubilis ; ramulis teretibus puberulis ad maturitatem glabrat- 1939] WOODSON——APOCYNACEAE OF TROPICAL AMERICA. VI 97 is; foliis oppositis longiuscule petiolatis membranaceis late ovatis apice breviter subcaudato-acuminatis basi late sed haud profunde cordatis 3-12 ст. longis 2-7 em. latis utrinque su- perne densius aspero-puberulis ; petiolis 0.7-1.5 em. longis pu- berulis; inflorescentiis pseudo-racemosis multifloris; pedun- eulo puberulo folia multo superante; pedicellis geminis ca. 0.4 ст. longis post maturitatem paulo acerescentibus ; bracteis minute lanceolatis vix 0.2 cm. longis; calycis laciniis ovato- lanceolatis acuminatis ca. 0.2 em. longis foliaceis extus pilosu- lis intus basi squama deltoidea erosa munitis; corollae pul- chrae albidae extus minute pilosulae intus omnino dense arach- noideo-villosulae tubo proprio 0.3-0.4 em. longo basi са. 0.15 em. diametro, faucibus late campanulato-conicis 1.5 em. lon- gis, ostio ca. 1 em. diametro, lobis late ovatis obtusis 0.8-0.9 em. longis patulis; antheris oblongo-sagittatis basi obtuse auricu- latis 0.6 em. longis glabris; ovariis oblongoideis ca. 0.15 cm. longis glabris; stigmate fusiformi apice obtusiusculo basi ap- pendieulato-digitato са. 0.2 ст. longo; nectariis 4 basi concres- centibus ovarium ca. dimidio aequantibus; folliculis (imma- turis) faleatis leviter moniliformibus 18-20 cm. longis glabris. —Mzxico: GUERRERO: Temisco, Sierra Madre del Sur, north of Rio Balsas, Distrito Adama, trail east from Stamp Mill, cleared overgrown slope, alt. 315 m., frequent, scattered, Nov. 9, 1937, Ynes Mexia 8751 (Herb. Missouri Bot. Garden, түре). At first glance, this species recalls Mandevilla convolvulacea (А. DC.) Hemsl., because of the somewhat abbreviated corolla with broad, campanulate throat. However, it shows all the generic characters of Fernaldia very clearly. The small corolla, with exceptionally short throat, readily distinguishes F. as- peroglottis from the other known species of the genus. The follieles are of especial interest, for they are the first records of fruit for Fernaldia. Those sent me, however, are too imma- ture for examination of the seed. Macrosiphonia Brachysiphon (Тотт.) A. Gray var. magnifica Woodson, var. nov., a varietate typica corollis magnis (ea. duplo majoribus) differt, tubo proprio 2.5-2.7 ст. longo ca. 0.15 em. diametro extus minute subarachnoideo-pilosulo, fau- [Vor. 26, 1939] 98 ANNALS OF THE MISSOURI BOTANICAL GARDEN cibus subtubuloso-conicis 1.7-1.8 em. longis, ostio ca. 0.6 cm. diametro, extus minute puberulo-papillatis, lobis oblique obo- vatis 2 em. longis patulis——Mexico: sonora: open granitic slopes, alt. 650-800 m., ridge south of Arroyo Gochico, east of San Bernardo, Aug. 5-9, 1935, F. W. Pennell 19524 (U.S. Nat. Herb., TYPE). This variety bears flowers about twice the size of those of the typical variety of M. Brachysiphon (specimens of which I have seen from near San Bernardo). Since normal M. Brachysiphon is otherwise a remarkably constant species, confidence can be placed in the erection of magnifica in a varietal capacity, al- though I believe the characters insufficient to warrant specific rank. STUDIES ON VARIATION IN GIBBERELLA SAUBINETII (MONT.) SACC. (FUSARIUM GRAMINEARUM SCHWABE)! MARY GODDARD Instructor of Biology, Woodrow Wilson Junior College, Chicago, Ш. Formerly University Scholar, Henry Shaw School of Botany of Washington University INTRODUCTION In recent years much attention has been given to variation in fungi, chiefly as a step in pathogenicity studies in combating diseases of economic plants. The exact nature of these varia- tions has been, and still remains, very controversial. In artifi- eial eulture, variations may be in the form of sectors or islands in apparently homogenous cultures, or the whole culture may vary perceptibly from the parent organism. The variations may be only temporary, reverting to the parental type in the next eultural generation; they may persist through several generations and then revert to the parental type; or remain as permanent variants; or, they may in turn form still other variants. Brierley (731) summarizes the theoretical modes of origin of new forms as follows: **(1) by adaptation of an existing form, (2) by hybridization of two existing forms, or by some other mode of genetic fusion and segregation, and (3) mutation.’’ He adds that what is apparently a new form may possibly be only the re-emergence and stabilization of a suppressed or la- tent character, or grouping of characters, or of a particular eyelogenie phase in a polyphasie organism. The objects of the experiments described in the first part of the paper were: (1) to determine whether variation ean be 1 An investigation carried out at the Missouri Botanical Garden in the Graduate Laboratory of the Henry Shaw Sehool of Botany of Washington University and submitted as a thesis in partial fulfillment of the requirements for the degree of doetor of philosophy in the Henry Shaw School of Botany of Washington Univer- sity. (99) [Vor. 26 100 ANNALS OF THE MISSOURI BOTANICAL GARDEN induced by altering environmental conditions, and to compare the variant with the parental type in order to obtain evidence of possible genetic change in constitution; (2) to determine whether there is a definite cycle of growth stages, such as mycelial, sporulating, and pionnotal, which can be influenced by environmental conditions; and (3) to observe whether the pionnotal stage reverts to the stage with aerial mycelium. The experiments described in the latter part of this paper were devised to show whether, when contrasting monosporous strains are grown together on culture media, the hyphal anas- tomoses result in heterocaryosis, thus producing new strains. HistoricaL REVIEW Variations in fungi have been referred to as mutations, salta- tions, discontinuous variations, dissociations, and semi-perma- nent variations. De Vries (’06) used the term ‘‘mutation”’ for a means of change which lies in the sudden and spontaneous production of new forms from old stock. Muller (’22) refers to mutation as a variation in the individual gene. ‘‘Saltation’’ has been used more or less synonymously with mutation. How- ever, it was probably used first by Stevens (722) to designate heritable variations for which the sexual stages are not known, and in which the cytological conditions have not been thor- oughly investigated. Das Gupta ('34) states that saltation in- cludes only those variations which are of the order of mutation in higher plants. Brierley (731) prefers to use the non-com- mittal descriptive term ‘‘discontinuous variation," which **has no genetic implications.’’ ‘‘Dissociation,’’ as defined by Leonian (732), the originator of this view, ‘‘is that phenome- non whereby a given organism traces the sphere of variability of the species." He states that no two members of a given species are identical, and that if tests could be sufficiently re- fined, differences between any two isolants of the same variety would probably be detected. Dissociations serve to bring forth such differences and to enlarge our species concept. Caldis and Coons (’26) state that the variants which they studied rep- 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 101 resent semi-permanent variations which differ from the parent form somatically rather than genetically. They suggest that the variations may be due to a nutritional disturbance which may be overeome when the necessary conditions are supplied. Studies on variation in fungi under cultural conditions were recorded at least as early as 1908 by Edgerton, who considered one of his variant forms of Glomerella as a mutation. In a later publieation (714) he remarked that this mutation was no doubt the minus strain of this fungus. Стар (14) observed a mu- tation in a pure Petri-dish culture of Phyllosticta, and later (715) he reported the sudden development of a minus strain from a plus strain in Coniothyrium pirimum. This phenome- non was observed four times in single spore cultures, and his explanation was that the minus strain was a ‘‘sport or mutant arising from the plus strain at irregular and unprognosticable intervals. Blakeslee (720) observed two mutations in non- sexually propagated races of Mucor genevensis. Other re- corded mutations are those of Burger (’21) in Colletotrichum gloeosporioides; Chodat (’26) in Aspergillus ochraceus and Phoma alternariacearum; Christensen (’26), Christensen and Davies (’37), in Helminthosporium sativum; Christensen and Stakman (’26), Stakman, Christensen, Eide, and Peturson (729), and Stakman, Christensen, and Hanna (729), in Usti- lago Zeae,in which they reported numerous mutations in mono- sporous cultures; Newton and Johnson (727) in Puccinia graminis Tritici; Sellsschop (729) in Gloeosporiwm; Roden- hiser (730) in Phlyctaena linicola; Blochwitz (731) in Citro- myces luteus, which was described at first as Penicillium ja- vanicum; and Eide (735) in Gibberella Saubinetu, in which he attributed the variations to true mutations or at least resulting from genotypic changes. Burkholder (723) isolated the gamma strain of Colletotrichum Lindemuthianum from beans in a field where only the alpha and beta strains had been known. Since it was nearer to the beta strain in its range of susceptible hosts, he concluded that it was a mutation from that strain. Following the studies of Stevens (722) on Helminthospor- ium, Mitter (729), in his work on saltations in the genus Fu- [Vor. 26 102 ANNALS OF THE MISSOURI BOTANICAL GARDEN sarium, found a greater difference between parent and variant than between species and species. Horne and Das Gupta (729) reported an ‘‘ever-saltating’’ strain in Diaporthe perniciosa. It was impossible to prevent saltation from occurring in every cultural generation. The resulting variant or strain was always the same. Тһе ability of the strain to saltate was independent of the medium and was inherent in the strain itself. In 1934, Das Gupta, after fur- ther work on these strains, reported saltation to be a conversion phenomenon. He concluded that properties of both strains were included in a single culture of DHo and even in a single hypha but that the properties might be spatially separated in the hypha. One strain of DHr had no visible expression in the presence of the other strain DHc. However, if small segments were cut from a young hypha of DHo mycelium, the majority would develop into DHr, and the remainder into DHo. Also the young DHc mycelium was able to convert a ОН» culture into с. Matsuura (730, ’30A, 732) described four types of saltations in Ophiobolus, Brachysporium, Alternaria, and ап Ascomy- cete from pears. Some of these saltations partially or totally reverted. Leonian (726) reported a reversible mutation in Phytoph- thora. Strain I gave rise at times to strain IV or a mixture of I and IV, and strain IV by mutation resulted at times in strain Chaudhuri (724) deseribed some saltations which were per- manent on Coons' agar and on oatmeal agar, but which re- verted to the original when transferred to potato-mush agar. Transfers made to Coons’ or oatmeal agar from the potato- mush agar did not produce the variant again. The preponderance of cases of saltations or mutations have been of a varietal or specific nature. However, Wiltshire (729, '32) reported a reversible saltation, where a Stemphyliwm cul- ture in the presence of a bacterial colony gave rise to an Alter- naria colony which in turn produced the Stemphylium colony again. Brett (’31) found a cyclic saltation in Stemphylium. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 103 Within a colony of Stemphylium, dark spore heads were pro- duced. Spores from these gave rise to Alternaria colonies in which the spores were produced in chains. The Alternaria spores gave rise to Stemphylium again, completing the cycle. Das Gupta (730) working with Cytosporina, obtained not only the characteristic bent filiform spores, but also oval spores, characteristic of the genus Phomopsis. Christensen (732) ob- served that sectors formed іп monospore cultures of Pestaloz- zia funerea produced colonies conforming to those described for Monochaetia. Cultures of the Monochaetia type were also obtained from spores produced in pustules of Pestalozzia fu- nerea on long-leaf pine. Saecardo (1884) distinguished the genus Pestalozzia from the genus Monochaetia on the number of setae, the former having two to six and the latter only one. Christensen believed that our previous conception of the genus Pestalozzia should be modified to include this form with one seta. Orthogenetie or unidirectional saltations have been reported by Crabill (715) in Coniothyriwm, referred to above; and Das Gupta (730) in Cytosporina. A particular strain may be reached in one saltation, or two or three saltations may take place before it has been developed. For example, Brown (726) and Mohandra (728) found that sometimes strain I gave rise to strain III, and at other times it produced strain II. The latter did not remain stable but gave rise to strain III. Das Gupta (730) observed a particular strain in Cytosporina to be reached by one, or by a series of three saltations. Burkholder (725), working with Fusarium mortiiphaseoli grown in eulture for a period of five years, discovered that it varied both in morphological charaeters and in virulenee but would revert when inoculated into a bean plant and re-isolated. He thought that this might explain the great number of species and varieties in Fusarium. Chaudhuri (731) has found the same to be true with some fungi with which he worked. Pal- miter ('34) suggested, from his observations of cultures of Venturia inaequalis, that this species was not homogeneous but composed of many strains differing physiologically and morphologically. [Vor. 26 104 ANNALS OF THE MISSOURI BOTANICAL GARDEN La Rue (722), from his work on Pestalozeia Guepini, stated that he found no evidence that distinct lines could be estab- lished by selection. However, Curzi (730) reported that by selecting transfers of sectors of a monoconidial culture of Fusarium Moronei, he obtained two non-reversible strains. Strain alpha was the result of selection, through several gen- erations, of the sector having the most profuse aerial my- celium; likewise, strain gamma was secured by selecting the sector having the scantiest aerial mycelium. Greene (733) found two types of variants in Aspergillus Fis- chert. In the first type, the ascospores produced cultures ргас- tically identical with the original stock culture, while the con- idia continued to give rise to the variant form. In the second type both ascospores and conidia produced the variant form. EXPERIMENTAL WORK A. Sources of Cultures.—Cultures of two strains of Gib- berella Saubinetti (Mont.) Saec. were obtained in the summer of 1937 from Dr. Carl J. Eide, of the Division of Plant Pathol- ogy and Botany at the University of Minnesota. He collected the original perithecial material on old corn stubble in grain fields in Minnesota in 1932-1933.1 These strains were desig- nated by him as A36-1-V and A43-4-I-I. The first was ob- tained from a single ascospore of the original perithecial ma- terial but did not in turn produce perithecia in culture. The second culture was from an ascospore of a perithecium which formed on an old piece of inoculum after it had been trans- ferred to fresh agar in a flask. It had been noted that the original ascospore culture, that from the ascus of a perithecium on corn stubble, had not formed fertile asci in culture on syn- thetic media. The same is true of this variant or strain. B. Materials and Methods.—For the greater part of the culture work the substratum used was potato-dextrose agar. The special media used were Brown's ‘‘synthetic potato-dex- trose’’ agar, Coons’ synthetic medium, Leonian’s agar, and 1 These strains, along with some others, were used in investigations for his doc- toral thesis (Eide, '35). 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 105 Richards’ agar. Malt extract agar medium was used for some of the stock cultures.? Single conidia were isolated with the Zeiss, and Bausch and Lomb micro-manipulators, using a glass needle in the manner described by Dickinson (733). The conidia were immediately transferred to fresh drops of agar on cover slips which were then inverted on Van Tieghem cells in Petri dishes lined with moist filter-paper. After germination of the conidia, the agar drops were transferred to culture media in Erlenmeyer flasks, Petri dishes, or test-tubes. Where cultures produced no con- idia, hyphal tips were cut off and used. This was done by trans- ferring a bit of the mycelium to ‘‘water agar’’ in Petri dishes. The scanty growth on this substratum made possible the isola- tion of single hyphae. In one instance the cutting tool consisted of a small piece of safety razor blade soldered to the end of a sewing needle, as described by Eide (735). At another time, fine dissecting scissors were used. The tips of the hyphae were cut off under a dissecting microscope and, with a small portion of the agar, were transferred by means of a sterile instrument to fresh agar drops on cover slips. After the mycelia had de- veloped slightly, the drops were transferred to media іп test- tubes, Petri dishes, or Erlenmeyer flasks, as in the case of the conidia. For cytological study, perithecia were dissected from the agar culture, killed and fixed in Hermann’s fluid, embedded in paraffin, and serial sections cut at 7 microns. The stain used was Haidenhain’s iron-alum haematoxylin, with phloxine as acounter-stain. The results were fairly good. ?'The potato-dextrose sE consisted of: peeled к т” gms.; dextrose, 10 gms.; agar, 17 gms.; and distilled water, 1 liter. Brown's ‘‘ synthetic potato- dextrose’’ agar: glucose, m gms.; asparagin, 2 gms.; K,PO,, 1.25 gms.; MgSO,, 0.75 gms.; agar, 17 gms.; and distilled water, 1 liter. Coons’ synthetic medium: sucrose, 7.20 gms.; dextrose, 3.60 gms.; MgSO,, 1.23 gms.; КН,РО,, 2.72 gms.; .02 gms.; agar, 17 gms.; and distilled water, 1 liter. Leonian’s agar: pep- tone, 5 gms.; KH,PO, 1 gm.; MgSO,, 1 gm.; dextrose, 20 gms.; agar, 17 gms.; and distilled water, 1 liter. Richards’ agar: cane sugar, 50 gms.; КМО,, 10 gms.; PO, 5 gms.; MgSO,, 2.5 gms.; FeSO,, a trace; agar, 17 gms.; and distilled water, lliter. Malt extract agar: malt extract, 33.5 gms.; agar, 20 gms.; and dis- ү water, 1 lite ater n consisted of: agar, 1.5 gms.; and distilled water, 100 се. [Vor. 26 106 ANNALS OF THE MISSOURI BOTANICAL GARDEN Small blocks of the mycelial culture of variants on agar were killed and fixed in Hermann's fluid, and embedded in celloidin. Serial sections were cut at 74 microns (Foster, 26) and stained in Haidenhain's iron-alum haematoxylin and phlox- ine. The nuclei and cell walls were well differentiated, but in- dividual hyphae could not be easily traced because of the com- pacted condition of the mycelium. For the study of hyphal anastomoses, the following proce- dure was used: Conidia from two contrasting strains were al- lowed to germinate on a thin agar drop on a cover slip sus- pended over a Van Tieghem cell on a glass slide. Anastomoses of the hyphae were observed under the high power of the micro- scope, and camera-lucida drawings were made. For the stained preparations of hyphal anastomoses, the same procedure was used except that the agar drop was placed on the slide instead of the cover slip. The same killing fluid and stains were used as for perithecia. Differentiation of the septa was difficult be- cause the greater part of the stain was removed from them in order to destain the agar drop. C. Types of Strains at the Beginning of the Experiments.— А43-4-І-І, when grown on potato-dextrose agar in Petri plates, produced only a scant amount of white to pale pink aerial mycelium. Тһе 214-2Y5-cm. salmon buff center of the upper surface was sometimes surrounded by two narrow bands, a wide band, and a narrow border. The first of these was purplish gray, the second vinaceous purple, the third pur- plish gray, and the border of submerged hyphae was vinaceous purple. In other cases, the two narrow bands were absent (pl. 9, fig. 1). The center of the reverse was the same pattern as the upper surface, with the following colors, beginning at the center: аргісо buff, dull violet black, dark vinaceous purple, dull violet black, and the border of dark vinaceous purple. There were numerous rudimentary perithecia on the upper sur- face. The dark vinaceous purple color was due to very numer- * Colors given are those of Ridgway's ‘‘Color Standards and Color Nomencla- ture." 1912. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 107 ous short thick-walled dark blue cells embedded in the agar. Conidia were abundant. A36-1-V, when grown on potato-dextrose agar in flasks ог Petri plates, produced an abundance of pale pink with some clay-colored aerial mycelium, cottony at first, then compacted with age (pl. 9, fig. 2). The bottom of the culture was dahlia purple to blackish red. The upper surface was level. Empty perithecia were numerous over the entire surface of the agar and many were embedded in it. Conidia were moderately nu- merous. For convenience in this paper, the former strain will be re- ferred to as A, and the latter as B. D. Preliminary Cultural Work.—In order to determine the relative stability or variability in each strain, a number of con- idia were isolated and grown under ordinary laboratory con- ditions on potato-dextrose agar. Forty-six conidia were isolated from strain B and transferred to agar drops in the manner described under ‘‘Materials and Methods." After germination of the conidia, the agar drops were transferred to potato-dextrose agar slants in test-tubes where they were allowed to grow until the surface of the medium was covered. No variation appeared in the test-tube cultures. Transfers were made in triplicate from each of the 46 test-tubes to potato- dextrose agar in Petri plates. After 25 days, the cultures ap- peared uniformly constant. About as much variation appeared between the plates from one conidium as between the sets of triplicates. Two and one-half months later, transfers were again made in triplicate to potato-dextrose agar in Erlenmeyer flasks. This time two types of variations appeared in six of the sets of triplicates, in from one to three flasks of each set (table т). The remaining 126 flasks were of the ‘‘normal’” type for B. Transfers of these variant cultures were made to Leonian’s agar in Erlenmeyer flasks, along with transfers of the pa- ***Normal’’ as used in this paper refers to the original B or original A when grown on potato-dextrose agar. [Vor. 26 108 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE I VARIATION IN SIX SETS OF TRIPLICATES OF SERIES B GROWN ON POTATO-DEXTROSE AGAR IN FLASKS AT ROOM TEMPERATURE Form of Color Amount of | Rudiments Triplicates variant Upper eri f surface Reverse mycelium | perithecia B 5 3 flasks ‘í Normal"? Much. Is- B35 9 flasks except for lands ex- B44 2 flasks Islands white is- |Normal tended Very few lands slightly above re mainder of colony B26 A m Hay's ma- Very nu- B32 roon to merous on B45 - flasks Whole colony| acajou red |Normal Little surface and | embedded agar rental type. B 26, B 32, and В 45° produced cultures identical with the parental type, while transfers from the white islands of B 5, B 35, and B 44 all produced cultures which were about 4 em. tall and very cottony, in contrast to the parental type which was about 1 em. tall, with the aerial hyphae more yellow- ish brown. Perithecia were not so abundant in the variant type and were embedded in the agar. Cultures B 5-1, B 35-1, and B 44-1, from Leonian's agar, were grown again on potato-dextrose agar in flasks at the same time as B 5 of the parental type. Тһе resulting cultures showed that В 35-1 and B 44-1 had reverted to the original ‘‘normal’’ B type identical with B 5, while B 5-1 remained a white cot- tony variant. * The system of nomenclature used in this series of cultural experiments is as fol- lows: А or B represents the original cultures with whieh this work was begun. The arabie numeral following is the number of the conidium isolated at random from that culture. Another arabic numeral following a dash represents the vari ant (island or seetor) from this type. For example, A17-1 represents the eulture from the first seetor or island from the seventeenth conidial isolate o A. I two sectors are formed in the same culture of А17, they are then designated аз А17-1 and A17-2. If A17-1 again forms a sector, it will be designated as А17-1-1. This system was suggested by Dr. E. C. Stakman as a graphie way of recording the genealogy of each variant. 1939] GODDARD— VARIATION IN GIBBERELLA SAUBINETII 109 B 5 and B 5-1 were included in the experiment on ** Attempts to Induce Variation in Strains," to be described later in this paper. Up to the present time B 5-1 has remained stable. Of 46 single conidial eultures, 40 have remained stable through five cultural generations on potato-dextrose agar ex- tending over a period of ten months ; 6 formed variants in the fourth eultural generation. Three variants produced the pa- rental type when transferred to Leonian's medium. Two of the remaining three reverted to the parental type when trans- ferred from Leonian's medium to potato-dextrose agar again. One variant has remained stable through five cultural genera- tions and on various media. Fifty-two single conidial isolates were made from culture A in the same manner as deseribed for eulture B. No variations appeared in the test-tubes, but when transfers were made in TABLE II VARIATION IN FOUR SETS OF TRIPLICATES OF SERIES A GROWN ON POTATO- rea AGAR IN II PLATES AT OM TEMPERATUR Color Amount А Triplicates rn of Rudiments Á Upper aerial bm variant surface Reverse mycelium perithecia A4 1 plate |Whole |Salmon orange |Cinnamon Some in сеп- Мопе eulture | with Eugenia | rufous with ter, border ed band Eugenia red | submerged bands А17 1 plate |Sector Same as above|Same as above |Same as None above A24 1 plate |Two S Same as upper|Same as None seetors | with addition | surface above of dark purple zone towar nter A43 1 plate |Whole Salmon orange |Same as upper|Only scant |None eulture | center, wide surface amount on zone of dar the dark greenish black, zone à narrow zone of Eu enia red [Vor. 26 110 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE III VARIATION IN FOURTEEN SETS OF TRIPLICATES OF SERIES A GROWN ON POTATO-DEXTROSE AGAR IN FLASKS AT ROOM TEMPERATURE Form Color Түмен Rudiments Triplicates of Upper aerial о variant surface Reverse mycelium | Perithecia А 51 flask Light salmon A 7 2 flasks orange center, А 9 1 flask |Whole | wide dark pur-/Same as upper|Very slight | Abundant А15 1 flask | culture} ple band, and growth on surface A25 2 flasks ght salmon A37 1 flask r А45 1 flask А 8 2 flasks A12 1 flask Same as A5 but|Same as A5 but A201flask |Whole | with Eugenia | with Eugenia |Very slight |Abundant 213 flasks | eulture| red border red border growth on surface A23 2 flas A46 1 flask A35 1 flask Light salmon orange with 4 Three | concentric nar-|Same as upper |None None seetors| row bands of | surface light Eugenia red triplieate to potato-dextrose agar in Petri plates, variations appeared in the four sets of triplicates which are recorded in table п. All except A17-1 produced the parental type in the next eultural generation, on potato-dextrose agar. About three months later, transfers were again made in triplicate to potato-dextrose agar in Erlenmeyer flasks, and the 14 variants which appeared this time were recorded in table тп. АП these possible variations, A5, A7, A8, A9, A12, A15, A20, A21, A23, А25, A35 (three sectors), A37, A45, and A46 were replated on potato-dextrose agar, and, with the exception of A35-1 (sec- tor 1 of A35), all the plates showed the characters of the pa- rental type. E. Attempts to Induce Variation in Strains.—Since strains А and B were found to be fairly stable in the preliminary ex- periments when grown on potato-dextrose agar at room tem- perature, the cultures were grown on different substrata and 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII ТЕ TABLE IV VARIATION IN MACROSCOPIC CHARACTERS OF A17 GROWN ON VARIOUS MEDIA AT DIFFERENT TEMPERATURES A17 Richards? Leonian's Potato-dextrose Coons’ pH 4.5 pH 4.8 pH 5.8 pH 6.5 18° С. Color Flesh-eolor mot-|Dark purple Seashell pink Salmon upper surface | tled with with wide rose-| center, earmine | center, remain- dian lake, dark pink border border, remain-| der dark pur- purple border der dark purple ple with slight н B it h tling of гав salmon buff pink Color Salmon with |Dark purple Same as upper |Same as upper reverse dahlia-purple | with Vandyke| but apricot buff mottling and | red border instead of sea shell pink fringed border Type of |Uniform me- |Оп отт me- | Сешег and spots/Uniform light growth dium-heavy dium-heavy of medium- growth of growth of growth of heavy growth of} aerial hyphae aerial hypae | aerial hyphae | aerial hyphae, remainder light growth Topography |Deeply genio 25 Very shallow con-|Short radial wrinkled ow, few short| centrie furrow, | furrows, very radial баек and large shal-| uneven margin lobed margin | low wrinkles Rudiments of |Few, small Very numerous | Very numerous |Very few perithecia at different temperatures in order to learn whether variations could be induced. Consequently, A17, A17-1, A4, A24, A43, A35, A35-1, B5, and B5-1 were grown in duplieate on Brown's “synthetic potato-dextrose’’ agar, Coons’ synthetic medium, Leonian's agar, potato-dextrose agar, and Richards' agar at 18°, 20°, 25°, and 30°C. and the macroscopic characters re- corded after 25 to 30 days. With the exception of A17—1, which produced no conidia and in which hyphal tips were substituted, single conidial isolates were used. On Brown's medium (pH 5.6), A17 showed the appressed type of growth, or with very little aerial hyphae in the center. The color of both upper and reverse surfaces was seashell pink at temperatures 189, 209, and 25? C. At 30? C. the color was [Vor. 26 112 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE IV (Continued) A17 Richards’ Leonian 's Potato-dextrose Coons’ pH 4. pH 4.8 pH 5.8 pH 6.5 20° C. Color Salmon with (Center and Seashell pink Salmon buff upper surface | very light wide border center, carmine | center, re- mottling of rose pink, wi border, remain- | mainder dark Indian lake uneven i der dark purple | purple with fringe of | of dark pur- with very slight dark purple ple around mottling of sea- center shell pink Color Same as upper|Same as upper | Same as upper Same as upper reverse but earmine in-| but apricot stead of rose buff instead of pink seashell pink Type of |Uniform light |Uniform me- Uniform light Uniform light h of growth rowth o dium-heavy growth of aerial| growth of aerial hyphae | growth of hyphae exeept aerial hyphae aerial hyphae | center of very light aerial growth Topography |Entire surface |Very shallow Very shallow con- Level, no fur- deeply wrin- | concentric fur-| centric furrow, | rows kled А | \ even margin Rudiments of Numerous Numerous Very numerous |Уегу few peritheeia pale salmon. Тһе surface was smooth and no rudiments of perithecia were formed. Variations on other media are shown in table ту. Growth of A17-1 on Brown's medium was appressed at 18? C., and appressed with few aerial hyphae at all other tem- peratures. The color was seashell pink; the surface was level, with no wrinkles or furrows; and no rudiments of perithecia were formed. Variations on other media are shown in table v. A4, on Brown’s medium, was mostly of the appressed type with very few aerial hyphae in the center. At 20° C., the growth did not exceed 1 cm. in diameter and developed no color. At 18° and 25° C., it was seashell pink, and at 30°, pale salmon color with orange pink reverse. The surface was 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII ТІЗ TABLE IV (Continued) A17 Richards’ Leonian’s Potato-dextrose Coons’ pH 4.5 H 4.8 pH 5.8 pH 6.5 259 C. Color Salmon Center and Бог- Orange pink with|Salmon buff upper surface der flesh pink, | radiate splashes| with wide bor remainder of dark purple der of dark dark purple pu mottled with flesh pink Color Salmon Same as upper Sua — Same as upper reverse but carmine with r ut salmo instead в. кегі dark} instead of flesh pink purple salmon buff Type of Mostly a Felt-like Uniform me- Uniform ngat growth pressed, only growth of dium-heavy growth of very slight aerial hyphae | growth of aerial hyphae uniform aerial hyphae pan wth of aerial hyphae Topography |Entire surface |Very shallow | Very shallow con-|Level except d wrin- concentric fur- or very shal- eeply kled furrows near center Rudiments of |None Numerous None None perithecia 30° C. Color Light apricot |Chatenay pink | Apricot buff Light salmon upper surface | orange orange Color Apricot buff |Apricot buff, | Apricot buff Light salmon reverse very deeply orange ottled with mine Type of |Appressed niform me- | Appressed M Appressed growth mostly; very ium-heavy light gro slight growth | growth of aerial nl rial aerial hyphae | center and far. hyphae rows Topography |Entire eb: Deep eoneentrie| Level except Level except va id furrow or none| 18-20 shallow few shallow near center ; radial furrows wrinkles in 18-20 radial center furrow None None None None Rudiments of perithecia [Vor. 26 114 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE V — IN MACROSCOPIC CHARACTERS OF A17-1 GROWN ON RIOUS MEDIA AT DIFFERENT TEMPERATURES А 17-1 Richards" Leonian's Potato-dextrose Coons’ pH 4.5 pH 4.8 pH 5.8 pH 6.5 18° C, Color Flesh pink Alizarine pink; | Orange pink with|Orange pink upper surface 1—rose slight mottling | with light red; sector 2—| of dark purple | fringe of dark alizarine pink pur with rose red border Deep seashell Acajou red with| Salmon with -— wes pink reverse aprieot buff dark purple ange margin; sec- | mottling light iem of or 1—Van- dark purple dyke red; eetor 2— acajou red Type of |Uniform me- |Uniform me- niform me- Uniform light growth dium-heavy dium-heavy dium-heavy growth o growth of growth of growth of aerial hyphae aerial hyphae | aerial hyphae | aerial hyphae Topography |Level— Level except Level except hint|Level—no fur- furrows urrows be- of radial fur- rows tween sectors | rowing and parent, and few radial wrinkles ne center Rudiments of |None None Few, very small |None perithecia smooth with no rudiments of perithecia produced. Variations. on other media are shown in table ут. A24, on Brown’s medium, showed no variation except at 30° C. where there was no growth. Growth was of the ap- pressed type with very little aerial hyphae in the center, the color was seashell pink, and rudiments of perithecia were lacking. Variations on other media are shown in table vu. A43, on Brown’s medium, was identical with A17 described above, except that there was very slight growth at 20° C. Va- riations on other media are shown in table үші. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII TABLE V (Continued) 115 А 17-1 Richards’ Leonian’s Potato-dextrose Coons’ pH pH 4.8 pH 5.8 pH 6.5 20° C. Color Orange pink |АПхагше pink | White to pale Orange with upper surface wi pink light Saws of circle of dark dark purple urple around center Color Orange pink (Саттпіпе White to pale Light salmon reverse mottled with pink range with aprieot buff dark purple border Type of ER light |Uniform me- | Extremely Uniform light growth growth of ium-hea slight growth, growth of aerial potas growth of appressed aerial hyphae rial hyph Topography |Deep concentric|Shallow con- Level Level—no fur- furrow, large | centric fur- rows wrinkles, very | row; 8-10 uneven border | short radial furrows near center Rudiments of |None None Very few Very few perithecia 25° C. Color Salmon color |Alizarine pink |Onion-skin pink |La France pink, upper surface with salmon some dark pur- center ple in border Color Apricot buff {Carmine red Buff pink Same as above reverse slightly mot- tled with apricot buff Type of |Uniform а Uniform me- Appressed "ge нурум ed ex- growth growth dium-heavy light growth t few aerial aerial MA growth of aerial hyph in scii e in aerial hyphae | center, border, | center and and furrows border Topography oncen- Shallow con- се Shallow | centric Furrow near center ; 19 sho rt radial furrows Shallow үз Үбі Вам ог опе; 5-10 short 5 long radial furrows Level, no fur- ws м е Rudiments of perithecia None None None None [Vor. 26, 1939] 116 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE V (Continued) А 17-1 Richards’ Leonian’s Potato-dextrose Coons’ pH pH 4.8 pH 5. pH 6.5 30° C. Color Salmon color |Flesh pink Orange pink Orange pink; upper surface sector—La Mee with traces of blue in dark purple er Color Apricot buff |Light salmon | Apricot buff Orange pink; reverse orange with sector—same slight carmine with slight mottling traces of dahlia purple and dark blue Type of grid, Бо of|Uniform me- | Uniform light ^ |Appressed ex- growth hyphae dium-heavy growth of cept few aerial lighter in growth of aerial hyphae hyphae in cen- enter aerial hyphae ter and cover- ing sector Topography м except — |Level—no fur- | Level—no fur- |Level—no fur- rows rows rows Rudiments of |None None None None perithecia A35, on Brown’s medium, varied only in color at the different temperatures. At 18° and 20° C., the color was seashell pink, at 25° it was salmon-buff, with the reverse seashell pink, and at 30° orange pink with safrano pink reverse. The growth type was appressed and no rudiments of perithecia were formed. Variations on other media are shown in table rx. A35-1 produced only the appressed type of growth on Brown’s medium, except at 20° C., where there was no growth. The color varied from seashell pink at 18°, through salmon buff with seashell buff reverse at 25°, to light salmon orange with orange pink reverse at 30°. The surface was smooth and no rudiments of perithecia were formed. Variations on other media are recorded in table x. B 5 and B 5-1 will be discussed later in this paper. TABLE VI VARIATION IN MACROSCOPIC CHARACTERS OF A4 GROWN ON IOUS MEDIA AT DIFFERENT TEMPERATURES А4 Richards" Leonian's Potato-dextrose Coons? pH 4.5 pH 4.8 pH 5.8 pH 6.5 18° C Color Flesh color Dark purple Seashell pink Salmon pink upper surface | mottled with | with wide rose| center, carmi center, remain- ndian lake pink border; border, remain- | der dark pur- and havin sector—dusky | der dar pom ple with slight very wide auricula pur- with slight mot-| mixture o border of le tling of seashell| salmon buff dark purple pink Color Salmon with |Заше as above |Same as upper, |Same as above reverse dahlia purple A i 2 mottling, very nstea (d wide border of shell pin dark purple Type of |Uniform me- |Medium-heavy |Center and spots |Uniform light growth dium-heavy growth of of medium- growth of growth of aerial hyphae;| heavy growth aerial hyphae aerial hyphae | seetor—lighf of aerial hyph growth of remainder light aerial hyphae | growth Topography ре Very shallow | Very shallow eon-|Some short ra- few shallow eoneentrie fur-| centric furrow, | dial furrows, wrinkles near | row; uneven and large shal- | very uneven enter margin low wrinkles margin Rudiments of |Very few Very numerous | Very numerous |Уегу few perithecia 20° C. Color Flesh color Center and wide| Salmon pink een-|Sa'mon buff upper surface | slightly mot- | border rose ter, carmine bor-| center and ed with In pink; lO der, remainder | dark purple ian lake and | wide dark purple border having dark band of pie with very slight purple fringe | purple mottling of sea- shell pink Color Salmon wit Same as above |Same as upper |Same as above reverse dahlia purple | but carmine but apricot b об пе and | instead of rose] instead of sea- dark purple ink shell pink fringe Type of Uniform me- Light К» of Uniform light rowth of Uniform light gro growth dium-heavy aerial hyphae wth of aerial hyphae | growth of with ring of very кісіні hyphae aerial hyphae | light growth around center Topography |Entire surface |Shallow concen- 77 shallow eon-|Level—no fur- E eeply wrin- trie furrows; entrie furrow, | rows led 8—10 short ra- aruis lo dial furrows large wrinkles center Rudiments of |Numerous Numerous Very numerous |Уегу few perithecia [Vor. 26 118 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE VI (Continued) A4 | Richards’ | Leonian’s Potato-dextrose Coons’ pH 4.5 pH 4.8 pH 5.8 pH 6.5 25° C. Color Salmon Center and bor-| One plate orange-|Salmon-buff upper surface der flesh pink;| pink with radi- | with wide bor- between, dark| ate splashes of | der of dark purple mottled| dark purple; purple with flesh pink| one plate orange-pink, dark purple mottled; secant — № size of plate, apricot buff Color Salmon Same as upper, Apricot buff with ere eolor reverse but carmine dark purple h dark pur- instead of mottling м border flesh pink Type of |Ошу very light |Felt-like Uniform light — |Uniform light growth gr growth of growth of rowth of aerial hyphae;| aerial hyphae | aerial hyphae; aerial hyphae mostly ap- secant—very pressed light growth of aerial hyphae Topography |Entire surface |Shallow сопсеп-| Very shallow con-|Level—hint of deeply wrin- м furrow centric furrow;| concentric ed e lar arge hint of rad furrow аа furrows ог lar wrinkles; no wrinkl eec Rudiments of |None Numerous None None peritheeia In general with strain A, media seemed to be responsible for greater variation in a given culture than temperature. Growth was greatest on Leonian's agar, decreasing in amount on po- tato-dextrose agar, Richards', Coons', to Brown's medium, where the development was least. Brown (726) found the opti- mum pH for growth in his Fusarium species to lie toward the acid end. This is in agreement with the work here on Gibberella Saubinetu. All cultures tended to produce the appressed type of growth, or with few aerial hyphae in the center on Brown’s medium. Through the series the amount of aerial hyphae increased with 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 119 TABLE VI (Continued) 27. Richards’ Leonian’s Potato-dextrose Coons’ pH 4.5 pH 4.8 pH 5.8 pH 6.5 30° C. Color Apricot buff; |Chatenay pink | Orange pink Orange pink upper surface | sectors (2), with light daphne pink fringe of dark purple Color Apricot buff; Light salmon | Cinnamon rufous Orange pink reverse sectors (2), orange with dahlia purple | slight carmine mottlin Type of |Appressed Uniform me- Uniform me- Very light growth mostly; very | dium-heavy dium-heavy growth of slight growth | growth of growth of aerial hyphae of aerial aerial hyphae | aerial hyphae yphae; вес- tors—light growth of . aerial hyphae Topography |Entire surfaee |20 or more Shallow concen- |Level except deeply wrin- | shallow radial| trie circle near | for very slight kled furrows center; 25-30 wrinkling in shallow to deep | center radial furrows Rudiments of |None None None None perithecia the amount of growth, being greatest on Leonian’s agar as is shown in pl. 10, fig. 4. Rudiments of perithecia were not produced on Brown’s me- dium at any temperature, but developed on all other media at 18° and 20° C., and on Leonian’s at 25° C. also. Lower tem- peratures seemed to favor development of more numerous and larger perithecial rudiments. Tschudy (’37) observed that species of Chaetomium do not develop normal perithecia on peptone media. Abundant primordia would form on the sur- face of the agar but would develop no further. The fact that mature perithecia developed on agar alone showed the peptone to be an inhibiting factor. The addition of 2 per cent alcohol to the sterilized nutrient agar had the same inhibiting effect on the development of perithecia as the peptone. In this investi- gation on Gibberella Saubinetu, larger and more numerous TABLE VII VARIATION IN MACROSCOPIC CHARACTERS OF A 24 GROWN ON VARIOUS MEDIA AT DIFFERENT TEMPERATURES A 94 Richards’ Leonian’s Potato-dextrose Coons pH 4.5 pH 4.8 pH 5.8 pH 6. 5 18S G, Color Flesh eolor Dark purple Seashell pink cen-|Salmon buff upper surface | mottled with | with wide гове) ter, border Pars center, remain- Indian lake; t border mine, rem dark pur- very wide dark {с=т with ple with slight border of slight mottling | mixture of dark purple of seashell pink | salmon buff lor Salmon with |Dark purple Same as upper |бате as above reverse dahlia purple | with Vandyke| except aprie ottling an red border buff instead of dark purple seashell pin rder Type of = me- |Uniform me- | Center and spots|Uniform light growth um-heavy dium-heavy of medium growth of ine wth of growth of heavy growth of| aerial hyphae aerial hyphae | aerial hyphae | aerial hyphae jeer gl light gro Topography |Few shallow Coneentrie fur-| Very shallow con-|Some short ra- wrinkles near center row, few short radial furrows, lobed margin centric furrow, and large shal- low wrinkling dial furrows, very uneven margin eee. of perithec Very few Very numerous Very numerous |Уегу few 20° C. Rudiments of perithecia Color Flesh color Center and wide} Seashell pink сеп- No growth upper surface | mottled with | border rose er, carmin Indian lake; ink; wide un-| border, remain- dark purple even band of der dark purple margin dark purple with very slight between g of sea- shell pink Color Salmon with |Same as upper |Same as upper |Хо growth reverse dahlia purple | but carmine but aprieot bu mottling and | instead of instead of sea- dark purple rose pink shell pink border Type of |Uniform light |Uniform me- Uniform light |No growth growth growth of dium-heavy growth of aerial hyphae | growth of aerial hyphae aerial hyphae | except ring of very light aerial hyphae around center Topography |Entire surface |Level—no fur- | Very shallow соп-| Мо growth deeply wrin- rows, uneven сепітіс furrow, kled argin hint of radial furrows ne ent Numerous Numerous Very numerous |None GODDARD—VARIATION IN GIBBERELLA SAUBINETII 121 TABLE VII (Continued) A 94 Richards’ Leonian’s Potato-dextrose Coons’ pH 4. pH 4.8 pH 5.8 pH 6.5 25° C. Color Salmon Center and bor-| Seashell pink cen-|Salmon buff, upper surface der flesh pink,| ter; remainder | wide border of remainder ark pur dark purple dark purple mottled with mottled with seashell pink; flesh pink ahlia purple traces in border Color Salmon Same as upper | Same as upper arg color reverse but carmine but cinnamon h dark pur- instead of rufous instead i. pois flesh pink of seashell pink Type of |Mostly ар” Felt-like ы е. Uniform light growth pressed; very | growth of grow growth of im d MAD aerial hyphae ады; Putas aerial hyphae growth of i hyphae Topography Very shallow | Very shallow con-| Level, except Entire surface de in concentric fur- row; 10 very shallow radial furrows; un- even margin furrows or large wrinkles one very shal- low concentric furrow around center Rudiments of |None Numerous None None perithecia 30° C. Color Apricot buff |No growth White Light salmon upper surface orange Color Aprieot buff |No growth White Light salmon reverse orange Type of |Appressed, No growth Appressed ex- Appressed growth mostly very tremely light slight growth growth of aerial hyphae Topography |Entire uiis No growth Level Level except oe eeply w few shallow led wrinkles in r Rudiments of |None No growth None None perithecia [Vor. 26 122 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE VIII VARIATION IN MACROSCOPIC CHARACTERS OF A43 GROWN ON VARIOUS MEDIA AT DIFFERENT TEMPERATURES A 43 Richards’ Leonian’s Potato-dextrose Coons’ H 4.8 pH 5.8 pH 6.5 18° C. Color Flesh color Dark purple Seashell pink cen-/Salmon bu upper surface | mottled with | with wide rose] ter, carmine bor-| center, remain ndian lake, pink border; der, remainder | der dark pur- very wide sectors (2), old| d rple ple with slight border of ose with with slight mot-| mixture of dark purple claret brown tling of seashell| salmon buff apices pink Color Salmon with urple Same as upper |Баште as above reverse dahlia purple | with Vandyke| but apricot та mottling, wide} red border; instead of sea- border etors (2), shell pink dark purple same as for upper surface Type of |Uniform me- |Uniform me- — vue Aon Uniform light growth dium-hea dium-heavy of m growth of growth of growth of меті өтей, of| aerial hyphae aerial hyphae | aerial hyphae;| aerial hyphae, seetors, light remainder light growth of growth aerial hyphae Topography Concentric fur-| Very shallow con-|Some short ra- Level, no fur- rows row, few short centric furrow, dial furrows, radial furrows, large shallow very uneven much-lo wrinkling margin margin — д of |Very few Very numerous | Very numerous |Very few rithee per perithecial rudiments were produced on Leonian’s medium, a peptone agar, than on other media employed. It has been stated previously that no fertile perithecia have been observed in strains A and B The color and color patterns varied widely with the different media used, and to a less extent with the temperature. With the decrease in temperature the colors became uniformly darker, usually red and dark purple. A deeper pigmentation was developed at 18° and 20° C. (see pl. 11). This agrees with the work of Crabill (15) on production of pigmentation in Comothyrium, but accords only in part with the statement of 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 123 TABLE VIII (Continued) A 43 Richards’ Leonian’s Potato-dextrose Coons’ pH 4 pH 4.8 pH 5.8 pH 6.5 20° C. Color Flesh color Center and Seashell pink cen-|Salmon buff upper surface | slightly mot- wide border ter, light car- center, dark tled with In- | rose pink, re- | mine border, re-| purple border dian lake, dark| mainder wide | mainder dark purple fringed| uneven band purple with border of dark purple| slight mottling of seashell pink Salmon with Same as upper | Same upper |баше as above reverse ahlia purple | but earmine m apricot kexa mottling and | instead of nstead o dark purple rose pink shell pin EA fringed border Type of [Uniform light |Uniform me- Uniform light — |Uniform light growth growth of dium-heavy growth of growth o aerial hyphae | growth of aerial hyphae aerial hyphae aerial hyphae | except ring of ry light aerial hyphae around center Topography |Deeply wrin- |Shallow concen-| Very shallow con-|Level, no fur- kled near cen- kis furrow, centrie furrow, ter, more shal| uneven margin| very large shal- low toward low wrinkles margi Rudiments of |Numerous Numerous Very numerous |Уегу few peritheeia Ashley, Hobbs, and Roistrick (737) that the optimum tempera- ture for development and pigmentation in Gibberella Saubi- netii is 24° C. Horne and Mitter (77) found the intensity of coloring in some Fusarium species to be associated with a high C:N ratio. Snyder (733) observed that the pH value, as well as the high earbohydrate content of the medium, may influence pigmentation. ‘‘The color of the mycelium"' as stated in Gäu- mann-Dodge (728, p. 233) ‘‘is largely dependent on the nutri- tion, especially on the reaction of the substrate.—The red mycelium of Gibberella Saubinetu on alkaline media becomes yellow on acid.’’ In the present investigation, strain A became yellow on Richards' medium (pH 4.5) but red and purple on Leonian's (pH 4.8) and potato-dextrose agar (pH 5.8). On [Vor. 26, 1939] 124 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE VIII (Continued) A 43 Richards’ Leonian’s Potato-dextrose Coons’ pH 4.5 pH 4.8 pH 5.8 pH 6.5 25° C. Color Salmon Center and bor-| Orange pink with|Salmon bu upper surface der flesh pink,| radiate splashes| wide border of remainder of dark purple | dark purple dark purple mottled wi flesh pink Color Salmon Same as upper | Cinnamon rufous |Salmon with reverse but carmine with radiate wide border instead of splashes of dark of dark purple flesh pink purple Type of Mostly ap- Felt-like Uniform medium-|Uniform light growth pressed, only | growth of heavy growth of| growth of ery slight uni-| aerial hyphae | aerial hyphae aerial hyphae form growth of aerial hyphae Topography ge surface |Level except ra-| Very shallow con-|Level, no fur- deeply wrin- di 8 сепітіс furrow, | rows led in the lobed hint of radial margin furrows or large wrinkles Rudiments of |None Numerous None None perithecia 30° C. Color Apricot buff |Сћаќепау pink | Apricot buff Light salmon upper surface orange Color Apricot buff Apricot buff Apricot buff Apricot buff reverse very deeply mottled with carmine Type of |Mostly ap- Uniform me- Appressed Aquen Extremely light growth pressed, very | dium-heavy Жы gro xir growth of slight growth | growth o rial nich aerial hyphae of aerial aerial hyphae —- and i. hyphae rOWS Topography |Entire surface |Shallow concen-| Level c. А - Level except d i trie circle near} 20 shallow very shallow center, 10-12 dial ferie nkling in shallow radial furrows None None None None Rudiments of perithecia TABLE IX VARIATION IN MACROSCOPIC CHARACTERS OF A 35 GROWN ON ARIOUS MEDIA AT DIFFERENT TEMPERATURES А 35 Richards’ Leonian’s Potato-dextrose Coons’ H 4.5 pH 4.8 pH 5.8 pH 6.5 159207 Color Flesh color pci purple Seashell pink cen- Salmon buff upper surface cag with | with wide rose| ter, carmine bor-| center, remain- an lake, pink border er, remainder | der dark pur- pen purple dark purple ple with slight border slightly mottled | mixture о with seashell salmon buff pink Salmon with {Dark purple Same as upper |Same as above reverse dahlia purple | with Vandyke bte apricot M ottling and | red border tead of s dark purple shell pink fringed border Type of Uniform me- — |Uniform me- Center and spots |Uniform light growth dium-heavy dium-heavy medium-heavy rowth of growth of growth of growth of aerial aerial hyphae aerial hyphae | aerial hyphae | hyphae, remain der light growth Topography |Level, no fur- |Concentrie fur-| Very shallow eon-|Same short ra- TOWS row, few short| сепітіс furrow, | dial furrows, radial furrows, and wide shal- very uneven lobed margin | low wrinkles margin pore of |Few, small Very numerous| Very numerous |Very few perithec 20° C. Color Flesh color Center о T Whitish to very |Salmon buff upper surface ro sim with | border pale pink center, remain- Indian eri pink, wi, u der dark pur- dark purple ven band of ple fringed border dark OMM bet Color Salmon with Same as upper |Same as above |Same as above reverse dahlia Met but earmine mottling, dark| instead of rose purple fringed| pink border Type of Uniform ue Uniform me- Very slight de- d ші c growth growth o ium-heavy velopment, ap- | growt aerial ЈАНА growth of pressed except aerial a erial hyph for few hy Topography pesci deeply Very shallow mene, no furrows|Level, no fur- ed in concentric fur rows Wu more row, hint of shallow toward, radial furrows, margin uneven margin Rudiments of Numerous Numerous None Very few [Vor. 26 126 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE IX (Continued) A 35 Richards’ Leonian’s Potato-dextrose Coons’ pH 4.5 pH 4.8 pH 5.8 pH 6.5 25° C. Color Salmon ~~ Center and bor-| Orange pink with|Salmon buff upper surface | mottled wi der flesh pink,| radiate splashes with wide deep sl ^ remainder of dark purple | border of violet dark purple dark purple mottled with h pi Color Salmon slightly|Same as upper | Cinnamon rufous |Salmon with reverse mottled with but carmine with radiate dark purple dull dusky instead of splashes of dark| border purple flesh pink purple Type of |Uniform light |Felt-like Uniform medium- |Uniform light growth growth of growth of heavy growth of| growth of aerial hyphae | aerial hyphae | aerial hyphae aerial hyphae Topography Shallow concen-| Very shallow con-|Very shallow Entire surface deeply wrin- led centric furrow, con — di row n wrinkles| hint of radial somewhat ra- | furrows or large) ter, Pye none dial, uneven wrinkles margin Rudiments of |None Numerous None None perithecia 80% С, Color Apricot buff |Сһаёепау pink | Flesh color Grenadine upper surface Color Apricot buff |Apricot buff | Apricot buff Grenadine pink reverse very deeply mottled with ine Type of Mostly ap- Uniform me- Heavy growth of |Light growth of growth pressed, very | dium-heavy rial hyphae aerial hyphae slight growth | growth of of aerial aerial hyphae hae Topography |Entire surface |8-12 very вһа1- 1 deep coneentrie|l concentric deeply wrin- low radial — pon TOW, re- kled furrows агріп, about inder wrin- 12 radial he kled and some- what warty None None None None Rudiments of peritheeia 1939] GODDARD—VARIATION TABLE X IN GIBBERELLA SAUBINETII 127 VARIATION IN MACROSCOPIC CHARACTERS OF A 35-1 GROWN ON VARIOUS MEDIA AT DIFFERENT TEMPERATURES А 35-1 Richards’ Leonian’s Potato-dextrose Coons’ p pH 4.8 pH 5.8 pH 6.5 I8* 0. Color Bittersweet Bordeaux with |Chestnut with ra-|Orange pink upper surfaee | pink few aprieot diating broken buff aerial lines of ox-blood yphae in red center Color Orient pink Bordeaux Burnt sienna Orange pink reverse Type of |Appressed Appressed Appressed Appressed growth Topography |Shallow wrin- |Level, no fur- |Level, no furrows|Some short kles over en- | rows radial fur- tire surface rOWS, very uneven margin Rudiments of |None None None None erithecia 20* C. Color Light salmon Bordeaux with | Light buff Orange pink upper surface | orange few apricot buff aerial hyphae in center olor Orange pink Bordeaux Light buff Orange pink reverse Type of |Appressed Appressed Appressed, very |Appressed growth light growth Topography |Shallow wrin- |Уегу shallow Level, no furrows|Level, no fur- kles toward concentric rows center furrow Rudiments of |None None None None perithecia Coons’ (pH 6.5) and pale pink to colorless. Brown’s (pH 5.6) the strain was very The hydrogen-ion concentration of the media was taken only at the beginning of the experiment before inoculations had been made, and it is quite probable that sub- stances produced by the fungus during growth on certain media tend to neutralize some of the acid, thus producing the red color. A correlation between rate of growth and pigmentation [Vor. 26 128 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE X (Continued) А 35-1 Richards’ Leonian’s Potato-dextrose Coons’ pH 4. H 4.8 pH 5.8 pH 6.5 25° C. n Color Salmon orange |Bordeaux Cinnamon rufous Salmon buff upper surface with broken diate lines М” dahlia purple Color Apricot buff |Bordeaux Same as above |Pale flesh color reverse Type of j|Appressed Appressed Appressed Appressed growth Topography od ver gl Very shallow Very shallow con-|Level, no fur- neentr concentric centric furrow | rows urrow furrow Rudiments of |None None None None perithecia 609540; Color Orange chrome |Briek red Flesh color No growth upper surface Color Medium salmon|Hay's russet Apricot buff No growth reverse orange Type of |Appressed Appressed AA mem of |No growth growth rial hyphae Topography |Level, по fur- (Level, no fur- | About 12-1 No growth rows rows sallow radial furr Rudiments of |None None None No growth perithecia in Alternaria Solan was pointed out by Bonde (’29). The maximum for both was at 25-30° Variations as referred to in the previous paragraphs are not of a permanent nature, as was shown in subsequent trans- fers to other media. They are the non-heritable changes due to environment, the ‘‘eco-variants’’ of Dickinson (732). А total of nine sectors was formed in six of the 360 plates used in this investigation, five being on Leonian's agar at 18? C., one on potato-dextrose agar at 25? C., one on Coons' me- dium at 30° C., and two on Richards’ medium at 30? C. Dis- tribution of sectors according to cultures, media, and tempera- ture are shown in table хі. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 129 TABLE XI DISTRIBUTION OF SECTORS ACCORDING ET CULTURES, MEDIA, AND TEMPERATURE Number of Н Cultures sectors Medium Temperature A4 T Leonian's 189 C. A4 1 potato-dextrose 25° C. A4 2 Richards’ 30° C A17-1 2 Leonian's 18° C A17-1 T C 4 30° C. A43 2 Leonian's 189 C. In an attempt to isolate these possible saltants, inocula were taken from the apex, center, and outer edge of each sector and transferred to fresh media. A transfer of the part not sector- ing was made at the same time, for comparison. Only the two sectors from A17-1 on Leonian's agar at 18? C. proved to be of a different form from the parent culture. These variants, designated as А17-1-1 апа A17-1-2, were identical in appear- ance. They will be discussed further under the next topic. B 5 and B 5-1 produced no sectors, islands, or other visible modifications when grown on the different media at different temperatures. B 5-1, on all media and at all temperatures, was lighter in color than the corresponding culture of B 5. Тһе colors ranged from ox-blood red to Eugenia red except on rown's medium, where it was light buff or pale pinkish buff to white. Depth of color increased with decrease in tempera- ture. The B series, like the A series previously mentioned, did not grow well on Brown's medium, the growth ranging from none (B 5 at 20° C.) through 1 em. (B 5-1 at 20? C.) to covering the surface of the medium at higher temperatures. No rudiments’ of perithecia were formed on this medium. On all other media and at all temperatures used, the aerial growth filled the Petri plate. No rudiments of perithecia were *The term ‘‘perithecial rudiments’’ has been used, because up to this time no mature ascospores had been found. One mature perithecium of B 5 on Leonian’s agar at 18° C. was found when serial sections were cut [Vor. 26 130 ANNALS OF THE MISSOURI BOTANICAL GARDEN produeed at 30? C. Distribution at all other temperatures is shown in table хп. TABLE XII DISTRIBUTION OF PERITHECIAL RUDIMENTS ACCORDING TO MEDIA AND TEMPERATURE Strain or Media variant 25° C. 20° C. 18° C. Coons’ B5 Numerous Very numerous | Very numerous В 5-1 None Very few Very few Richards" B5 None Numerous Numerous B5-1 None None None Potato- B5 Numerous Very numerous | Very numerous dextrose В 5-1 None None Numerous Leonian's B5 Numerous Very numerous | Very numerous В 5-1 None Numerous Numerous Vasudeva (730) found that certain strains of Fusarium when grown on shallow plates of an acid phosphate medium readily gave rise to strangely diverging sectors. Many of these sectors did not prove to be variants and were therefore termed ‘‘false sectors." Matsuura (732) observed that temperature and com- position of the nutrient media influence the frequency of muta- tion, being greater on potato decoction agar. Stakman, Chris- tensen, Eide, and Peturson (729) have shown there were more numerous variations in Ustilago Zeae on some media than on others and that they occur at comparatively high temperatures. However, Tu (730) was unable to induce permanent variations in species of Fusarium by subjecting them to different media and incubating them at various temperatures. Brown (726, 28) reported that saltations in Fusarium were more frequent on concentrated Richards’ solution agar than on many other media. This was confirmed by Chaudhuri (731). Christensen (726) observed more numerous mutations in strains of Helmin- thosporium on one media than on another under similar con- ditions. In 1937 he and Davies demonstrated the frequency of mutation of Helminthosporium on a bacteria-staled medium. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 131 One race cultured for seventeen years produced eighty-one varieties from seventeen colonies on the bacteria-staled me- dium, while on the same number of colonies on potato-dextrose agar none was produced. Paxton (733) was able to secure consistent mutations in Helminthosporium sativum on Cza- pek's medium, with the NaNos omitted. An average of five sectors in each plate was observed. On Czapek's medium which was used as a check, very few sectors were formed. Chaudhuri (731) found that the greater number of variants would revert to the original form when grown on some medium or when re- turned to the original host. He considered saltation in fungi to be purely a nutritive phenomenon, unless it be a rare case of true mutation. Coons and Larmer (730) obtained variants of Cercospora beticola in cultures on artificial media. They re- garded them as modified forms with nutritional disturbances playing a role in their development. Caldis and Coons (’26) expressed the same opinion for variants in Colletotrichum and Cladosporium. This disturbance might have been due to the connections with the substratum being severed by the drying of the mycelium, or the variant might have arisen from cells the protoplasm of which had been poisoned or had been affected by some other unknown factor. Chodat (’26) favored the premutation theory of de Vries as an explanation for the appearance of variants in the various media. His belief was that the media did not produce the variants but only made visible the pre-existing mutations. Shear and Wood (713) found it impossible to trace any causal relation or connection between most of the phenomena of variation observed in Glomerella and the conditions of en- vironment to which the cultures were subjected. Induced variation by heating the ascospores of Eurotium was reported by Barnes (’28, ’31). Some of these variants had remained stable over a period of about four years. He suggested that, apart from the probable nuclear changes, a general derangement of the physiological balance of the cell may be responsible for variation. Dickson (’32) and Goldring (736) were unable to obtain any variants by this method. Chris- у [Vor. 26 182 ANNALS OF THE MISSOURI BOTANICAL GARDEN tensen (729), and later Mitra (731), observed that certain lines of Helminthosporium species mutate only at the higher tem- peratures for growth. Christensen found the optimum tem- perature for mutations to be 25-27? C., while Mitra noted that it was 30? C. In the present investigation on Gibberella Saubi- netii, more variations appeared at 18° C. than at the three higher temperatures, as is shown in table xr. F. Constancy of Mycelial and Conidial Forms.—In the pres- ent investigations, also in Fusarium studies carried on by Brown (728), sectors were formed which were myeelial in char- acter and produced few or no conidia. At other times in mycel- ial types, sectors have been formed with very numerous conidia and very little aerial mycelium. On A17-1, a sector of A17, no conidia developed when transferred to fresh potato-dextrose agar and grown at room temperature as described earlier in this paper. А17, although mycelial in character, produced many conidia under the same conditions. A17 and А17-1 were grown on five different media and at four different temperatures as described in the preceding ex- periment, and the macroscopic characters are represented in tables rv and v. They were examined microscopically to de- termine the constancy of these forms under various cultural conditions. These results are given in table xm. Inoeula from the two sectors of А17-1 were transferred to fresh potato-dextrose agar in Petri plates. A transfer of in- oculum of A17-1 was made at the same time for comparison. А17-1-1 and А17-1-2 remained the typical sector color, or perhaps the color was slightly deeper. The upper surface was Eugenia red to Vandyke red and the reverse was apricot buff to acajou red. The mycelium was mostly appressed, with very little aerial hyphae, and was somewhat wet in appearance. The surface was smooth except for one (rarely two) concentric furrows and numerous short shallow radial furrows. These cultures were definitely of the conidial type. A17-1 remained a mycelial type and produced по сопа on potato-dextrose agar at room temperature. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 133 TABLE XIII PRODUCTION OF CONIDIA IN LINES A17 AND A17-1 UNDER VARIED ENVIRONMENTAL CONDITIONS. A 17 (mycelial form producing numerous conidia) : Tempera- р Potato- | ture Richards’ dextrose Leonian’s Coons’ Brown’s 18510; Many Few Few Many Few 209 C. Many Very few | Very few Few None 25* C. Very many| Few Few Few Very few 30° C. Very шапу | Few Very few Very few Very, very few A 17-1 (mycelial form producing no conidia) : 1890; Very few None por. те None n 2 вес no re nu- merou 20° C. Very few Very few | None None None 259 C. Few Very few | None 1 plate—many| None 1 plate—very few 30° C. Very few Very few | None None Very few Inoeula from A17-1-1 and A17-1-2 were transferred to po- tato-dextrose agar in test-tubes. Instead of the appressed conidial form again, an aerial form was produced. It was pale pinkish and powdery in appearance, and mieroscopie exami- nation showed numerous conidia. ATTEMPTS то INDUCE THE PIONNOTAL STAGE TO REVERT TO THE AERIAL MycELIAL STAGE In cultural work with species of Fusarium, variants have developed which were in the form of pionnotes.* However, so far the writer has been able to find no instance reported of a culture completely reverting to the aerial mycelial phase after it once had gone into the pionnotal phase. In this work A35-1 * Pionnotes is merely a biological term for an effuse conidial stage, with a maxi- mum of conidia and a minimum of aerial mycelium, which, as a rule, is slimy when young and resin-like or powdery-dry іп old age. (Wollenweber, 713. [Vor. 26 134 ANNALS OF THE MISSOURI BOTANICAL GARDEN developed as an appressed form with very numerous conidia. When grown on various media at a rather wide range of tem- peratures, as described under ‘‘ Attempts to Induce Variation,’’ the growth was always appressed except on potato-dextrose agar at 30° C. where a light growth of aerial hyphae de- veloped. At 20° C. on Leonian’s agar the color of this culture was Bordeaux. When transfers were made to malt extract agar in tubes the color reverted to the light salmon orange characteristic of this culture on this medium, but the growth had a slimy appearance with no aerial mycelium. When ex- amined microscopically, the growth was found to consist of a maximum of conidia, the pionnotal stage. A transfer to Leon- ian's agar made at the same time produted the Bordeaux color again, but the mycelium, instead of being completely appressed, was largely aerial. Conidia were very numerous and were 3- to 7- (mostly 5-) septate. A subsequent transfer to potato-dextrose agar in a Petri plate produced a moderately heavy growth of aerial hyphae which were pink with a yellowish tint. This growth soon col- lapsed, and the color of the upper surface changed to Eugenia red and the reverse to acajou red to Vandyke red. To learn whether the pionnotal phase would revert to the aerial mycelial phase, the series of transfers were made as shown in fig. 1. In each case, a small portion of mycelium was transferred with a sterile needle to the fresh media. The Ro- man numbers in fig. 1 represent the stages in the development of the aerial mycelial phase from the pionnotal phase, and are as follows: I. Pionnotal (described previously in text). IL. Appressed type, salmon orange with very faint zoning of Eugenia red. Very numerous conidia. III. Appressed type, salmon orange with Eugenia red center. Very numerous conidia. IV. Wide zone of aerial hyphae about 1 cm. from the center, remainder appressed. Salmon orange except for a wide zone of irregular radially striped Eugenia red coinciding with the zone of aerial hyphae. Very numerous conidia. ЕН 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 135 V. Aerial mycelial stage. Aerial hyphae cottony, white to pale pink, reverse surface acajou red. Conidia fairly nu- merous. VI. Dense aerial growth. Aerial hyphae cottony, white to slightly mottled with Eugenia red, substratum Eugenia red. Few or no conidia. M malt extract { lest- tube P potato - dextrose agar I I-VI Stages ЈЕ ws p es of ‚ the аегта/ mycelia ase from O Petri pb ale the pionnotal phase. I Explanatio in text. Fig. 1. Graphie representation of the development of the aerial mycelial phase from the pionnotal stage. The culture at the right in the third generation was of type I at first but later developed an area of type V. In this series of cultures there seemed to be a transition from the pionnotal phase with no aerial hyphae (I) and the appressed type (II, III), through the aerial and appressed forms (IV), to the aerial mycelial forms (V, VI); from the orange color (I, II), through the orange and red (III, IV), to the red substratum (V, УІ); from forms with a maximum or very numerous conidia (I, II, IIT, IV), through forms with fairly numerous conidia (V) to forms with few or no conidia (VI) (see pl. 12). OBSERVATIONS ON SECTOR FORMATION Figure 2 shows the form and comparative distance from the inoculum of all variant sectors formed in an attempt to induce 156 [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN 6 5 Fig. 2. Sectors formed in cultures ved at various temperatures on different media: -1, on Leonian's agar a °С. One sector mm. from inoculum, nearer one 8 mm. Phi inoculum; 2, А "ea on Coons’ agar at 30? C. Sector 4 mm. from inoculum; 3, А 4, on Leonian's agar at 18° С, Sector starts at inoculum; 4, А 4, on Richards’ agar at 30? C. Both sectors start 3 mm. from inoculum; 5, A 43 on Leonian's agar at 18? C. One sector 16 mm. from inoculum, nearer one 8 mm, from inoculum; 6, А 4 on potato-dextrose agar at 25° C. Sector (secant) 3 mm. from inoculum, 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 137 variation by varying the temperature and medium. It ean readily be seen that sectoring began at varying distances from the center or from the piece of inoculum. One sector (А 4 on Leonian's agar at 18? C.) started at the piece of inoculum and another (А 43 on Leonian's agar at 18? C.) started 8 and 16 mm. from the inoculum. In one, both sectors on the plate started at the same time, but in the other two cases one sector started at approximately twice the distance of the first sector from the inoculum. Christensen (726) found that more sectors started near the edge of the colony than near the center in H elmintho- sporium. Brown (726) found that more saltations took place near the center or in the older mycelia and that they occurred in irregular patches. In a total of 360 Petri plates, six plates formed sectors. Of these, three plates formed two each, and three formed one each, making a total of nine sectors. The chance of getting a plate with one sector then is 9/360 or 1/40, and the chance of getting a plate with two sectors would be 1/40 x 1/40 or 1/1600. Yet in this experiment there were three plates with two sectors each, or 3/360 or 1/120. The question then arises as to why there were so many cases of double sectors. In two sectors the growth type was observed to be the same in both ; or if the sectors were differentiated on the basis of deeper or lighter pigmentation than the remainder of the culture, both showed this character; or if it were ability to produce conidia, both exhibited this character. It seems then that whatever factor or factors were operating to pro- duce one sector tends to produce two. It acts in a qualitative as well as т a quantitative way. ATTEMPTs TO PRODUCE INTERMEDIATE STRAINS BY Crosstne Two MorPHOLOGICALLY DIFFERENT STRAINS Brierley (’29) suggested that certain recorded variations in fungi might be explained on the basis of the ‘‘mixochimaera’’ hypothesis. This term was used first by Burgeff (714) for a mycelium in which nuclei and cytoplasm of distinct types were associated as the result of hyphal fusion. [Vor. 26 138 ANNALS OF THE MISSOURI BOTANICAL GARDEN Hyphal anastomoses are common in fungi. Ward ('88), Beauverie and Guillermond (703), and Brierley (722) have demonstrated anastomoses in Botrytis. Ezekiel (724) observed fusions between hyphae of two varieties of Sclerotinia ameri- cana but no further growth. Matsumoto (721) noted in Rhizoc- tonia Solani fusions between hyphae of the same or closely re- lated strains; or strains which have recently originated from the same ancestral type. He was of the opinion that it was not a sexual process. Stevens (’22) reported that hyphal fusions were common in Helminthosporium. Dosdall (’23) and Chris- tensen (’26) observed numerous fusions of germ tubes in Helminthosporium, Christensen noting as many as seven in- stances of lateral fusion in one series. Ocfemia (’24), in his work on Helminthosporium, showed figures of anastomoses very similar to those of the present author on Gibberella Saubi- netii as shown in pl. 14. Drechsler (723) noted іп Helmintho- sporium Bromi the same type of fusion of germ tubes as did Christensen, but the former observed also that some of the hyphal fusions would swell into subglobose bodies and pro- liferate short irregular processes of inflated segments, the whole resulting in dark brown, knotty masses of mycelium. Some of these continued to increase in size, developing into subspherical sclerotia readily visible to the naked eye. He did not cultivate these further but was of the opinion that they rep- resented immature perithecia. Aside from these observations on hyphal anastomoses, there are the investigations of those who have studied hyphal fusions as such, or who have attempted to synthesize new types from pre-existing strains or even species. Burgeff (714, 715) pro- duced a neutral strain by mechanically mixing the cell contents of a plus and a minus hypha of Phycomyces nitens. This prod- uct, as previously mentioned, he termed ‘‘mixochimaera.”’ Leonian (’30) attempted to induce mixochimaera in Fusarium moniliforme by growing two morphologically different types together in nutrient media, but no new strain was produced. However, Hansen and Smith (732, 734, 735) reported that heterogenic types of Botrytis cinerea resulted from mixing 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 139 together two homogenie strains of the fungus in the same cul- ture. Mixing of cell contents by anastomosis resulting in ‘theterocaryosis’’ was suggested as the mechanism of this phenomenon. Interspecifie combinations were made in the same way by using two distinct species. The authors suggested that the produetion of these aberrant homotypes was due to gene changes brought about in some way by interspecifie anas- tomosis. Davidson, Dowding, and Buller ('32) used hyphal anas- tomosis as a character for differentiation of species of Micro- sporum. They observed fusions between mycelia of the same species but never between different species. Dickinson (732) isolated fusion cells which were the product of the anastomosis of two contrasting strains of Fusarium fructigenum. On isola- tion from the subsequent growth of such fusion cells, the cul- tural eharaeters of the two parent strains were found un- changed. Das Gupta's observations (734) of hyphal anas- tomoses in Diaporthe perniciosa led him to suggest that the fusion of DHc with DHr mycelium exerted an influence on the latter and brought about the conversion of DHr into DHc mycelium. The present work was undertaken, first, to find if hyphal anastomosis took place when conidia® from two contrasting strains of Gibberella Saubinetii were allowed to germinate on the same drop of nutrient agar (this procedure has been de- scribed under ** Materials and Methods") ; and second, to de- termine whether new and different strains were produced as a result of this fusion. The following combinations were made: A35-1 x B5-1; A35 x A35-1; and B5 x B5-1. Camera-lucida drawings of hyphal anastomoses are shown in pl. 14, figs. 1-8. Conidia of A35-1 and B5-1 were germinated separately on nutrient agar drops, and hyphal anastomoses occurred also in single spore colonies (pl. 14, figs. 9-11). The agar drops with the germinated conidia were trans- ferred to Petri plates of nutrient agar. In the first two combi- * During several months in culture, A35 lost its capacity for produetion of со- nidia. Hyphal tips were substituted. [Vor. 26 140 ANNALS OF THE MISSOURI BOTANICAL GARDEN nations, there were sharp lines of demareation between the two strains showing that each had inhibited the growth of the other. In the third combination the two colonies intermixed for the most part. Conidia were isolated along the line separating the two colonies, or along the surface where the two colonies over- lapped. Of the total of 56 conidia isolated from the A35-1 x В5-1 combination, 31 produced the A35-1 type and 25 the B5-1 type. In the second combination, A35 x A35-1, 44 conidia were isolated and all exhibited the A35-1 type. Of the 55 conidia iso- lated from the third combination, B5 x B5-1, 28 were the B5 type and 27 the B5-1 type. No intermediate or new strain re- sulted from mixing the mycelia. As can be seen from the data recorded, there was approxi- mately a 1:1 ratio of the original types which appeared in the isolates from the mixed cultures of A35-1 x B5-1, and B5 xB5-1. The occurrence of only one original type in the isolates from the * A35 x А35-1” cross may be explained by the supposition that A35, which was not producing conidia when the cross was made, still did not produce conidia. This evidence obtained from these crosses and re-isolations indicates that although hyphal anastomoses were common between the different pairs of variants, the strains remained separate. CYTOLOGICAL STUDY No intensive study of the whole cytological phenomenon in variants of Gibberella Saubinetii was attempted. However, ob- servations were made of structures which proved to be peri- thecial rudiments ; also of the nuclear condition in hyphal anas- tomoses. An examination of the perithecial rudiments showed that the vast majority had not developed to maturity. One peri- thecium, nevertheless, which had been produced in a culture of B 5 on Leonian’s agar at 18° C. was found to contain mature ascospores (pl. 13). The asci had probably already disinte- grated, for the ascospores appeared to be loose in the peri- thecial cavity. The ascospores were 4-septate. Hide ('35) found them to be 3-septate in the strains which he examined. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 141 Four-septate ascospores are exceptional in this species (Wol- lenweber and Reinking, 735). In the study of hyphal anastomoses, the nuclear condition was found to be more complex than the data on isolation of single-spore colonies from the mixed cultures would lead one to suspect. Dickinson (’32) found the fusion cells in hyphae of Fusarium fructigenum to be binucleate, although both nuclei were sometimes found in one half of the cell. The hyphal cells are generally uninucleate except in the fusion cells, or sometimes in cells adjacent or very near to the fusion cells. In this study, lateral processes were observed to push out from adjacent filaments and come together and fuse. The wall between them disintegrates, thus forming a connection between cells of the two filaments. Plates 15 and 16 show various nuclear conditions, many of which cannot һе explained until some additional information has been gained. Figures 2 and 3 of pl. 15, and figs. 2a, 5a, 6a, and 7a of pl. 16 show binucleate fu- sion cells either before or after one nucleus has migrated into the other half of the cell, conditions described by Dickinson (732, fig. 6) for Fusarium fructigenum. In other fusion cells one or both nuclei appear to have divided once or more, and in a few cases some of the daughter nuclei are seen migrating through the anastomosing tube (pl. 15, figs. 4, 5 and 7, pl. 16, figs. 1, 2b, 4, 5, 6b). D'Oliveira (736, pls. 4 and 7) reported a similar phenomenon in Fusicladium. His figures showed anastomoses between two hyphae, and between two conidia. In the former, nuclei are seen which have recently divided, and in the latter some recently divided nuclei are seen passing into the anastomosing tube. No instance of caryogamy in these anastomoses was observed. All fusion cells were two- to several-nucleate. Discussion AND CoNCLUSIONS Gibberella Saubinetu appears to be a very variable species exhibiting a number of forms or phases differing from each other in type and rate of growth, color, and amount of conidial production. These characters may be influenced by media and [Vor. 26 142 ANNALS OF THE MISSOURI BOTANICAL GARDEN temperature. Brown (726) remarks, with regard to Fusarium fructigenum, that **the tendency of these Fusarium strains to saltate is a function of the cultural medium.’’ That the ma- jority of variations recorded in this paper were due to reaction to the environment is evidenced by the return of the variants to the original form when grown under the original conditions of culture. Others, however, did not revert to the original form but continued to produce the same type of variation or to form still other variant types. One culture, originating as a sector from A35, went through a cycle of growth phases. It was mentioned under ‘‘Sources of Cultures’’ that the original cultures used in this study were ob- tained from Dr. Eide, who had isolated them from corn stubble in 1932 and 1933. He described his original ascospore isolate A43—4-I, from which this A43-4-I-I or A line developed, as fol- lows: ‘‘ ‘Normal’ type; characterized by abundant, cottony, aerial mycelium, red, often with a tinge of yellow. The bottoms of the cultures were pink to deep Eugenia red." (Eide 732, р. 12, table 4, and p. 13.) A43-4—I-I or A of this paper is deseribed in detail on page 106, and is illustrated in pl. 9, fig. 1. Briefly, it was an orange pink form at first with scant aerial mycelium but with age produced abundant thick-walled deep purple cells in the substratum. Upon further culture, A35-1 was produced as a sector in one of the conidial isolates (table тп). It differed from A35 in having no aerial mycelium and developed no deep purple thick-walled hyphae. It was of the conidial or sporulat- ing type. On five different media and at four different tempera- tures it produced this appressed type of growth with very nu- merous conidia, but on potato-dextrose agar at 30? C. a light aerial growth resulted. When transferred from Leonian's agar at 20? C. to potato-dextrose agar and malt agar, the cul- ture assumed the pionnotal phase. In subsequent transfers to potato-dextrose agar, as is shown in fig. 1, the pionnotal phase changed to the aerial mycelial phase with few or no conidia. This phase seems comparable to the description of Eide's orig- inal ascospore isolate, although a stock culture of the original could not be obtained for purposes of comparison. 1939] GODDARD—VARIATION IN GIBBERELLA SAUBINETII 143 Whether this culture will again pass from the aerial mycelial phase, through the appressed or conidial phase and the pion- notal phase, to the aerial mycelial phase again is still being investigated. Upon the basis of data obtained thus far it seems a more logical conclusion that there is a definite cycle of growth phases through which this fungus passes, than to conclude that all these variations represent separate strains within the species. It has been definitely shown that the pionnotal phase reverts to the aerial mycelial phase. This, it seems, is a very significant contribution. SUMMARY 1. A number of conidial isolates of two strains of Gibberella Saubineti were allowed to grow for several generations on potato-dextrose agar to determine the relative stability of the strains. Only one permanent variant was formed in one strain and two in the other strain. 2. Nine conidial isolates, including the three variants, were grown on Brown's, Coons’, Richards’, Leonian’s, and potato- dextrose agar at 18°, 20°, 25°, and 30? C., to induce variations. Ecovariants, or temporary variants due to environment, as well as some permanent variations, were produced. More vari- ations, temporary and permanent, occurred at the lower tem- peratures and on Leonian’s agar. Growth also was best on Leonian’s agar. The optimum temperature for growth was 25? C. 3. Mycelial and conidial forms were only fairly constant when subjected to variations in temperature and media. Nu- merous conidia appeared in sectors of the mycelial types which had previously formed no conidia; and conidial types have changed to aerial forms producing only very few or no conidia. 4. The pionnotal stage in one strain reverted to the aerial mycelial stage which seemed to answer the description of the original ascospore isolate from corn stubble. It completed a cycle of growth by passing from the aerial mycelial phase through the conidial and appressed phase, through the pion- notal phase back to the aerial mycelial phase. [Vor. 26 144 ANNALS OF THE MISSOURI BOTANICAL GARDEN 5. No new or intermediate strains resulted from crossing two morphologically different strains. While nuclear migra- tion occurred between hyphal anastomoses, there was no evi- dence that caryogamy took place in the hyphal anastomoses. 6. The two facts: (1) production of two sectors at about the same time, and (2) identical mutant sectors, favor the hy- pothesis that the saltation is somatic rather than germinal. The soma, rather than the germ-plasm, might more readily be expected to saltate more or less simultaneously at diverse points under the proper stimulus. Germinal changes are usually somewhat at random and even if two occurred in the same culture it might confidently be expected that they would be different mutants. ACKNOWLEDGMENTS Many persons have assisted the writer during the course of this study and she wishes to express her appreciation to all of them. The work was first begun at the University of Minne- sota under the direction of Dr. E. C. Stakman, who suggested the problem and was very helpful during the early stages. Later it was extended in the laboratories of the Henry Shaw School of Botany of Washington University under the direc- tion of Dr. C. W. Dodge, whose continued assistance made its completion possible. Acknowledgment is also due Dr. C. J. Eide for the stock cultures used, to Dr. Edgar Anderson for advice on the genetieal aspects of the problem, to Dr. Louise Dosdall for helpful suggestions, and to President Roscoe Pul- liam of the Southern Illinois State Normal University for one year's leave of absence from the faculty of that institution in order that this project might be more easily carried out. BIBLIOGRAPHY Ashley, J. N., B. C. Hobbs, and H. Roistrick (’37). Studies in the biochemistry of micro-organisms. LIII. The erystalline coloring matters of Fusarium cul- т (W.G. Smith) Басе. and related forms. Biochem. Jour. 31: 385-397. Barnes, B. (’28). Variations in Eurotium herbariorum (Wigg.) Link, induced by the action of high temperatures. Ann. 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WE p deseription of strains together with a dis- cussion of the "EA at present adopted in the classification of Fusarium. : 285- Burgef, H. (14). Untersuchungen uber Variabilität, Sexualität und Erblichkeit bei Phycomyces nitens, lora : - or --------, (715). Ibid. 17 тъй. 108: 323—448. 13 Burger, O. F. (721). Variations in Colletotrichum реннде» (Penz.). Jour. Agr. Res. 20: 723-736 Burkholder, W. H. (723). 4% gamma strain of Colletotrichum lindemuthianum (Saee. et Magn.) B. et C. Phytopath. 13: 316-323 = (25). ты in а member of the genus Fusariwm grown in culture jus a period of five years. Amer. Jour. Bot. 12: 245—253. шр 2) A y^ and G. H. Coons (726). Achromatie variations in pathogenie fungi. ead. Sei, Papers 6: 191-936. белин: H (724). A description of Colletotrichum biologicwm, nov. sp., and observations on the oecurrenee of a saltation in the species. Ann. Bot. 38: 735- 744. 1 pl. ? figs. ——— — — —, (781). Nutritive saltation in fungi. Ind. Bot. Soc., Jour. 10: 154. Chodat, F. (726). El ame. sur la mutation de: les champignons. Soc. Bot. Genéve, Bull. 18: 41-144. 52 figs. Christensen, C. (732). mn races and the production of variants in Pestalozzia unerea. Torrey Bot. Club, Bull. 59: 525-544. 6 Christensen, J. J. (725). Physiologie specialization dd mutation in Helmintho- sporium баеым. Phytopath. 15: 785—795. 4 figs. 16:20). Physiologie pup and parasitism of Helmintho- sporium bium. Minn. Agr. Exp. Sta., Tech. Bull. 37: 1-99. 12 pis. 1 › (729). The influence of Nul ie on the frequency of айса in са sativum. Phytopath. 19: 155-162. 3 figs. [Vor. 26 146 ANNALS OF THE MISSOURI BOTANICAL GARDEN d F. R. Davies (7/37). Nature of variation in Helminthosporiwm sativum. Mycologia 29: 85-99. 3 figs , and E. C. Stakman (726). Physiologie specialization and mutation in Ustilago zeae. Phytopath. 16: 979-999. 11 figs. Coons, G. H., and F. 6. Larmer (730). The physiology and variations of Cerco- spora "sd en in pure culture. Mich. Acad. Sci., Papers 11: 75-104. 3 pls. Crabill, C. H. (714). Mutation in Phyllosticta. Phytopath. 4: 396. —— — — —, (15). Dimorphism in Coniothyrium pirinum Sheldon. Amer. Jour. Bot. 2: 449-467. 15 figs. Curzi, M. (730). Su la mutazione di un ifomicete (Fusarium moronei). Atti del 11° Congr. Naz. Microbiol, Milan. 49—52 Das Gupta, S. N. (730). Studies in the genera Cytosporina, Phomopsis, and Dia- porthe. YI. On the occurrence of saltation in Cytosporina and Diaporthe. Ann. Bot. 44:349—384. 2 pls. 9 figs. , (734). Ibid. VI. On the eonversion of one бұға of Diaporthe perniciosa into another. Roy. бос. Lond., Phil. Trans. В. 223: 121-161. 4 pls. --------- (736). Saltation in fungi. Loses Univ. Stud. 5: 1-83. Davidson, A. M., E. В. Dowding, and A. Н. В. Buller (732). Hyphal fusions in der nét ad Canadian Jour. Res. 6: 1-20. 3 pls. 22 figs. De Vries, H. (706). Species and varieties, their origin by mutation, ed. 2, 847 рр. Chieago. и S. (732). The nature of saltation in Fusarium and Helminthosporium. Agr. Exp. Sta., Tech. Bull. 88: 1—42. 6 figs. (733). The technique of isolation in microbiology. Phytopath. 23: М 357-367. Diekson, Н. (732). The effeets of X-Rays, ultra-violet light, and heat in produeing saltants in Chaetomium cochliodes and other fungi. Ann. Bot. 46: 889-405. 4 pls. 1 fig. D'Oliveira, B. (736). Notas para o estudo do género Fusicladium. II. Tipo de germinação dos conídios dos Fusicladia dindriticum, pirinum е eriobotryae, Rev. Agron. 24: 20-51.7 pls. Dosdall, L. T. dic Faetors Ге әде кке кенде of Helminthosporium sativum, n. Agr. Exp. Sta., Tech 6 pls. а, C. cm) Some онеро species s bia ы ARN Jour. Agr. Res. 24: 641-740. көлігінің C. $ (708). Physiology and development of some anthraenoses. Bot. . 45: 367-408. 1 pl. --------> (714). Plus and minus strains in the genus Glomerella. Amer. Jour. Bot. 1: 244—254. 2 pls. Eide, C. J. (735). The pathogenieity = > мен of Gibberella Saubinetii (Mont.) Saee. Minn. Agr. Exp. Sta., Tech. 106: 1-55. 7 pls. 9 figs. Ezekiel, W. N. (724). Fruit-rotting Selerotinias е The Ameriean brown-rot fungi. Md. Agr. Exp. Sta. Bull. 271: 87-142. 22 figs. "is d А. В. ( x: The dps method for сағана 58 Bot. Gaz. 81: 339. Güumann, E. A., and С. W. Dodge (728). Comparative morphology of fungi, ed. 1, p. v New York. Goldring, D. (736). The effect. of environment upon the production of sporangia and sporangiola in Blakeslea trispora Thaxter. Ann. Mo. Bot. Gard. 23: 527- 542. pl. 25 1939] | GODDARD—VARIATION IN GIBBERELLA SAUBINETII 147 | Greene, H. C. (733). Variation in single spore cultures of Aspergillus Fischeri. = Mycologia 25: 117-138. 5 figs. Hansen, H. N., and R. E. Smith ('32). The mechanism of variation in Imperfect Fungi: Bag cinerea. т 22: 953-964. 4 figs. 34). Interspecific anastomosis and the origin of new Ub of Imperfect Еи Abstr. in Phytopath. 24: 1144-1145, , (785). The origin of new types of Imperfect Fungi from Бао eo-eultures. Zentralbl. f. Bakt. II. 92: 272-279. 6 figs Horne, A. S., and J. Н. Mitter (727). Studies in the genus Fusarium. V. Factors determining septation and other features in the section Discolor. Ann. Bot. 1: 519-547 , and S. N. Das Gupta (729). Studies in the genera Cytosporina, Phomopsis, and Diaporthe. I. On the oceurrence of an ever-saltating strain in Diaporthe. Ibid. 43: 417—435. 7 figs La Rue, C. D. (722). Тһе results of seleetion within pure lines of Pestalozzia Guepini Desm. Geneties 7: 142-201. 10 figs. and Н.Н. Bartlett (7/22). A demonstration of numerous distinct strains within the nominal species Pestalozzia Guepini Desm. Amer. Jour. Bot. Leonian, L. H. (726). Тһе morphology and To of some Phytophthora mutations. Phytopath. 16: 723-730. 1 pl. 3 , (730). Attempts to induce ‘‘ ања, іп Fusariwm monili- forme. Ibid. 20: 895-001. 2 figs. , (732). The pathogenicity and the variability of Fusarium monili- forme о corn. W. Agr. Exp. Sta. Bull. 248: 1-15. 6 figs. Matsumoto, Т. ('21). his in the physiology of fungi. XII. Physiologieal specialization in Rhizoctonia Solani Kuhn. Ann. Mo. Bot. Gard. 8: Matsuura, I. (730). Experimental bid on the saltation in fungi (Preliminary report)—I. Оп the saltation of Ophiobolus Miyabeanus Ito et в с parasitie on rice gea ти бос. Agr. Sci., Trans. 2: 64-89. 1 pl. — · On various types of saltation, Jour. Plant Protec. 17: 7 pp. (Japanese). mos n Jap. Jour. Bot. 3: (68). 193 „(кај VT. On the saltation in the genus ‘As dt VER Ibid. 19: 121- 139. 1 e 1 EA Mitra, M. (731). A comparative study of ста and strains of itii ори on certain Indian cultivated crops. Brit. Мус. Soc., Trans. 54—293 зе Н. (729). Studies in the genus Fusarium. VIII. Saltation in “к section olor. Ann. Bot. 43: 379—410. мілага, К. К. ('28). А study of the changes undergone by certain fungi in arti- fieial eulture. Ann. Bot. 42: 863-889. 3 pls. 2 figs В. » J. (722). Variation due to change in the шалады gene. Amer, Nat. 56: T nu м, and T. Johnson (727). Color mutations in Puccinia graminis tritici (Pers.) Erikss. and Henn. Phytopath. 17: 711—726. 1 pl. 4 figs Ocfemia, б. О. (724). The Helminthosporiwm disease of rice occurring in the outhern United States and in the Philippines. Amer. Jour. Bot. 11: 385—408. 6 pls. Palmiter, D. Н. (734). Variability in the monoconidial cultures of Venturia in- aequalis. Phytopath. 24: 22—47 [Vor. 26, 1939] 148 ANNALS OF THE MISSOURI BOTANICAL GARDEN Paxton, 9. E. (733). Consistent mutation x Helminthosporium sativum on a no- nitrogen medium. Ibid. 23: 617—619. Ridgway, R. (712). Color standards and e votaste inte. Washington, D. C. Rodenhiser, Н. A. (730). Physiologie specialization and mutation in Phlyctaena linicola Speg. Phytopath. 20: 931—942. 4 figs. Saccardo, P. A. (784). Sylloge Fungorum 3: Sellsschop, J. P. E. (29). A mutation in Glocosporium from lemon. Phytopath. 19: 605. 1 fig. Shear, C. L., and A. K. Wood (713). Studies of fungous parasites belonging to the "M Като. U. S. Dept. Agr., Bur. Plant Ind. Bull. 252:1-110. 18 m 4 figs Snyder, ү. C. (733). Variability in the к» -wilt organism, Fusarium orthoceras var. Pisi. Jour. Agr. Res. 47: 65-88. 8 figs. Stakman, E. C., J. J. Сыйда, C. J. Hide, and B. Peturson ('29). Mutation and hybridization in Ustilago zeae. I. Mutation. Minn. Agr. Exp. Sta., Tech. Bull. 65: 1-66. 10 pls. ? figs. , and Е. W. Hanna (729). Mutation in Ustilago геае. Abstr. in Phytopath. 19: 106. Stevens, F. L. (722). The Helminthosporium foot-rot of wheat, with observations n the morphology of Helminthosporiwm and on the occurrence of saltation in the genus. Ill. Nat. Hist. Surv., Bull. 14: 77-184. 28 pls. 55 Sys Tschudy, R. H. (737). Experimental morphology of some spec hae AL actions of species of Chaetomiwm under various на of cultive Jour. Bo : 657—665. Tu, C. (730). Physiologie specialization in Fusarium spp. ыры head blight of small grains. Minn. Agr. Exp. Sta., Tech. Bull. 74: 1-27. 8. Vasudeva, R. N. S. (730). On the occurrence of ‘‘ false cin > jn cultures of Fusarium fructigenum. Brit. Mye. Soc., Trans. 15: 9 pl. Ward, H. M. ('88). A lily disease. Ann. Bot. 2: 319—382. Wiltshire, S. P. (729). A Stemphyliwm saltant of an Alternaria. Ibid. 43: 653- 662. 1 pl. 4 figs. -------, (3 A reversible Stemphylium-Alternaria saltation, Ibid. 46: 343-352. 1 pl. 2 figs Wollenweber, H. W. (713). Studies on the Fusarium problem. Phytopath. 3: 24- 50. 1 pl. 1 fig. — — ————, und, О. А. Reinking (735). Іле Fusarien, ihre Beschreibung, яру iene und Bekümpfung, Berlin. PLATE 9 EXPLANATION оғ PLATE Cultures grown on potato-dextrose agar at room temperature. С Fig. 1. Petri plate culture of strain A. Fig. 2. Petri plate culture of strain B. Fig. 3. Petri plate culture of B 5-1, a variant from strain B (fig. 2). PLATE 9 ANN. Mo. Bor. Garb., Vor. 26, 1939 GODDARD —VARIATION IN GIBBERELLA SAUBINETII 152 [Vor. 26, 1939] ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 10 Variations in a single culture due to differences in the composition of the medium, Temperature, 25° C. 1 2 „8. 4 5 А 17 on Brown's agar. A 17 on Coons' agar. А 17 on Richards? agar. А 17 on Leonian’s agar. А 17 on potato-dextrose agar. PLATE 10 26, 1939 ANN. Мо. Вот. Garb., Vor. тенден IN GIBBERELLA S GODDARD —VARIATION EXPLANATION OF PLATE SES cau: 4-42. PLATE 11 Variations in a single culture due to differences in temperature. Grown on | Fig. 1. A17 at 18° C. Ann. Mo. Вот. Garb., Vor. 26, 1939 PLATE 11 GODDARD —VARIATION IN GIBBERELLA SAUBINETII E [Vor. 26, 1939] 156 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 12 Culture A 35-1 on potato-dextrose agar, showing some stages in the develop- ment of the aerial mycelial phase from the pionnotal phase. Stage I, the pionnotal phase, was grown in test-tube cultures. Fig. 1. Stage II. — type, salmon orange with Eugenia red center; very numerous conidia Fi age III. gue type, salmon orange with Eugenia red center; very numerous conidia. Fig. 3. Stage IV. Wide zone of aerial hyphae about 1 em. from the center, striped Eugenia red coinciding with the zone of aerial hyphae; very numerous conidia. This stage is intermediate between the appressed type and the aerial mycelial type. It was also intermediate in color between salmon orange and Eugenia red. Stage V. was identieal in appearance with Stage VI. Conidia were fairly nu- merous. Figs. 4 and 5. Stage VI. Dense «и mycelium; aerial hyphae 2” white to slightly mottled with Eugenia red ; or no conidia (see fig. 1 in text). is a culture developed from the vto region of the test-tube culture, and ~ 4 from the aerial mycelium of the same culture. The two resultant cultures are identical. ANN. Мо. Bor. Garb., Vor. 26, 1939 4 5 GODDARD —VARIATION IN GIBBERELLA SAUBINETII PLATE 12 [ Vor. 26, 1939] 158 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 13 The microscopic structure of a fertile perithecium. Figs. 1-3. Serial sections of a fertile perithecium from a Petri-dish culture of B 5 grown on Leonian's agar at 18? C; x 350. In fig. 3, a median seetion, аясо- spores are plainly visible. Fig. 4. Тһе ascospores of fig. 3 shown at a higher magnifieation; x 865. Note that these spores are 4-septate (3-septate ascospores are usually found in this species). ANN. Mo. Вот. Garb., Vor. 26, 1939 PLATE 13 3 4 GODDARD — VARIATION IN GIBBERELLA SAUBINETII EXPLANATION оғ PLATE PLATE 14 Hyphal anastomoses drawn with the aid of a eamera lueida from living material; x 625. Figs.land2. В5-1 x А35-1. Figs.3and4. А 35 x 35-1. Figs. 5, 6, 7, and 8. В5 x B65-1. Figs. 9 and 10. В 5-1. A 1. ANN. Mo. Вот. GARD., Vor. 26, 1939 PLATE 14 sat ae \ | GODDARD-—VARIATION IN GIBBERELLA SAUBINETII EXPLANATION оғ PLATE PLATE 15 Hyphal anastomoses drawn with the aid of a camera lucida from stained material; x 450 Figs. 1, 2, and 3. A 35 x A 35-1; the remainder, B 5 x B 5-1. _ Figs. 5-9 inclusive show 6 fusions or beginnings of fusion of hypha X with h ; M ypha Y. | Fig. 10 shows hypha X fusing with ћурћа 2. ANN. Mo. Вот. GARD., Vor. 26, 1939 PrATE 15 ИНЬ УЫС. ас. O 9 GODDARD—VARIATION IN GIBBERELLA SAUBINETII . PLATE 16 Hyphal anastomoses drawn with the aid of a camera lucida from stained EXPLANATION OF PLATE "fl o Nes ‘ Figs. 1-8. B5 x B 5-1; x 450. .9. A single hypha showing type of branching; x 225. втш Өсө Hmm ae ANN. Mo. Вот. GARD., Vor. 26, 1939 GODDARD—VARIATION IN GIBBERELLA SAUBINETII PLATE 16 Annals of the Missouri Botanical Garden Vol. 26 SEPTEMBER, 1939 No. 3 TREE TEMPERATURES AND THERMOSTASY ERNEST 5. REYNOLDS Formerly Physiologist to the Missouri Botanical Garden Associate Professor in the Henry Shaw School of Botany of Washington University ТЕ is commonly assumed that, with minor variations, the temperature of the plant body is essentially that of the sur- roundings, or to be specific that the root system practically holds the temperature of the soil, while the stem temperature is that of the air. Stiles (736) states, for example: “Апу differ- ence in temperature, however, between the plant and the me- dium in which it lives is generally very slight, and it has been stated that the temperature of growing shoots is not as a rule more than 0.3? C. above that of the surrounding atmosphere." Pfeffer (706, Vol. 3, p. 381) says: ‘‘Hartig found, for instance, that the interior of a tree trunk sank to -13? C. during a winter when the air was frequently at -15° C. to -22? C. in spite of the upward flow of heat from the warmer roots." Although nu- merous more or less intermittent records of the temperatures in tree trunks have been made by use of thermometers, it has not been possible, until the invention of modern thermographs, to follow the temperatures, minute by minute, through long periods of time, as in the study to be reported upon here. Variations of tree temperatures from those of the surround- ing air have been noted from time to time. Elevated temper- atures were believed to be eaused by local, excessive respira- ANN. Мо. Bor. GARD., VoL. 26, 1939 (165) [Vor. 26 166 ANNALS OF THE MISSOURI BOTANICAL GARDEN tion or to slow cooling following periods of high air tempera- tures due to slow heat conduction of the tissues. Temperatures below those of the air have been assigned to the slow heat con- duetion of the tissues, or to the transpiration stream pulling cool water from the soil up through the stem. Mason ('25) de- scribed a partial thermostatic action in the growth center of the date palm which ‘‘is able to neutralize much of either cold or heat as the case may be, that has penetrated from without.’’ This he attributed essentially to **the ascending sap current, with a temperature acquired from the soil from which it is drawn by the roots.’’ Various investigators had previously noted occasions when tree temperatures were either above or below those of the air, but no regulation of tree temperatures except through insulation effects of the bark and the equaliza- tion action of soil temperature has been seriously considered. From the results to be reported here it will be evident that under certain environmental conditions there is a distinct thermostatic action in trees involving new concepts of physical conditions within them and resulting in significant benefit to them. APPARATUS AND METHODS In planning this study the effort was to attain accuracy to- gether with a minimum of artificial conditions. It was recog- nized that conduction of heat into and out of the organism by the apparatus might lead to serious error and that intermittent observations might miss important information. After an in- vestigation of several of the chief types of recording instru- ments, a resistance thermometer was adopted as the most sat- isfactory. The apparatus, kept in operation for about four years, was an adaptation of a commercial instrument manufac- tured by the Brown Instrument Company and composed es- sentially of two main units, the recording instrument (fig. 1) and three sensitive resistance bulbs (fig. 2). The resistance wires of pure electrolytic nickel were enclosed in pyrex glass protective tubes. Although glass has some disadvantages, especially its relatively low rate of temperature conduction, its characteristics seemed less likely to cause error than those = E мый = © = ~ m: 1939] REYNOLDS—-TREE TEMPERATURE AND THERMOSTASY 167 of other materials. As a means of reducing so far as possible any conduction of heat or cold either from or toward the se- lected tissue and to give added mechanical protection, a celeron fiber tube encased the glass down to the sensitive elements. A three-wire cable connected each of the bulbs with the automatie recorder. The recording instrument is described briefly as follows by the manufacturers: “Т consists of а Wheatstone bridge with two ratio arms of equal resistance, a third arm consisting of a resistor having electrical resistance equal to that of the bulb at maximum temperature, and the fourth arm a resistor having resistance equal to that of the bulb at minimum temperature; a switeh permitting transposition of the bulb into the bridge circuit in place of the latter resistor; a galvanometer and storage battery, with standardizing rheostat, being connected to the bridge at the proper points; the galvanometer scale being suitably calibrated in temperature units, 77 This is a completely automatic, electrically driven apparatus with synchronized clock and a three-record chart in different colors having a temperature range of —35? C. to +40° C. The chart moved at the rate of 14 inch an hour, and a record of each bulb was made every 3 minutes with a 20-second depression of the needle. Small differences of temperature may most readily be recorded over a range limited only by the recording device; and several different records, covering long periods of time, may be kept simultaneously on the same sheet of paper for di- rect comparison. A cottonwood tree (Populus deltoides Marsh.), with a trunk about 10 inches in diameter at 30 feet from the ground, where the bulbs were inserted, was selected for study. In setting up the apparatus the three bulbs were distributed as follows: One was inserted with its sensitive element at the center of the tree. The second bulb was placed on the southeast side of the tree, as near the cambium layer as possible, by boring a hole from the opposite side of the trunk. Hence the tissues external to the bulb were left intact, and necessary mechanical support for the bulb was obtained. Both holes were bored to the diameter of the celeron tube to obtain a tight fit. The tight-fitting appa- ratus was undisturbed for the period of the experiment, so [Vor. 26 168 ANNALS OF THE MISSOURI BOTANICAL GARDEN that its physical continuity with the tissues of the plant was not broken. Much of the success in obtaining the detailed and continuous record described later may be ascribed to this fact. The third bulb, which recorded the air temperature, was placed in a small eage built in imitation of the U. S. Weather Bureau shelters, to screen it from direct sunlight and rain. During the growing season all the bulbs were shaded by the tree foliage. The immediate problem was to determine accurately the fluctuations of the tree temperatures in relation to those of the air and to discover any indication of a control of the tempera- ture by the tree itself. It was possible to read readily from the record-charts 0.25- degree changes of temperature and to compare almost minute for minute the temperatures of the three bulbs. Photographic reproductions of many of the original graph-records made dur- ing the 4-year study are cited by date іп the body of the text and may be identified thereby. The diagram in fig. 3, which is an exact сору of a typical medium temperature record, will help to understand the general principles followed in inter- preting the graphs reproduced at the end of the paper. GENERAL PRINCIPLES FOR READING THE CHARTS 1. The usual record for a 24-hour period shows (fig. 3) the air temperature beginning to rise at from 5 to 8 a. m., reaching a maximum between 1 and 5 p. m., followed by a decline in the late afternoon and night. Commonly the air-temperature line (A) crosses the tree-temperature lines (H and C) during the early morning rise of the air temperature and again in the afternoon with its decline. At these intersection points (W, X, Y, and Z) the air temperature is momentarily the same as that of the tree center (W or Y) or cambium (X or Z). Many modi- fieations of this daily record appear, as will be seen in the graphs, and even complete inversions of the air temperature may occasionally take place when it increases during the night or decreases during the day. Nevertheless, this fundamental type must constantly be borne іп mind when these records аге being examined. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 169 2. Air-temperature increases, before the morning intersec- tions of the temperature lines, cannot raise the tree temper- atures because the air temperature is below those of the tree. 3. Air-temperature decreases, before the afternoon inter- sections of the temperature lines, cannot lower the tree temper- atures because the air temperature is still above those of the tree. Fig. Typieal record Жы the three tree Lp 69-4 tures. The lines A (air), H (tree center) and C (cam- bium) are the first ү 2 ји dig pie gd records for the 24-hour period, 7 a. m. W and X are the a. m. intersections of A with H er C respectively, and Y 2 Z the eorresponding intersections made during the p. . de- cline in Eo Later, W, X, Y and Z are рылым **iso-ther nodes In the original graph-records the vertical 5% represent 0.5? C. and the horizontal lines reading digg елінде to top, 1- tolle intervals fro The ers on the horizontal lines of the gr tx records are o p^ disregarded, but the tem perature lines are eorreetly numbered. In the graph- -records and in this figure, therefore, temperature inereases from left to right and ime advances upward. Fig. 3 4. However, such an increase before the intersections W and X in the morning, or a decrease before the intersections Y and Z in the afternoon, does slow down the rate of the temperature changes in the tree and hence will prolong the time between the minimum air temperature and the minimum tree temperatures in the morning and between the maximum air temperature and the maximum tree temperatures in the afternoon respectively. 5. From 2 and 3 above, it will be evident that, in calculating the direct effect of air-temperature change upon the tree tem- peratures, only the number of degrees after the morning inter- sections and the afternoon intersections respectively should be counted. 6. The same intersections must be used as the basic points in ealeulating the degree-hours as described later. [Vor. 26 170 ANNALS OF THE MISSOURI BOTANICAL GARDEN 7. Aslong as the eambium temperature is appreciably above that of the center the latter continues to rise regardless of whether the air temperature is rising or falling. 8. Tabulations of maxima and minima or of mean temper- atures have not usually been presented, although heretofore most of the published data on tree temperatures have been given in this form. Such tabulations are usually inadequate and often inaccurate due to infrequent or arbitrarily timed ob- servations. Much of the value of the present records would be lost, as has been true of former published data, by the use of mean temperatures, since averages iron out individual differ- ences from which, in studies of this type, principles may be determined. Maxima and minima, as ean be seen from numer- ous examples in these records, very often cover considerable and irregular periods of time and are not merely points, as has usually been tacitly accepted in former studies upon this subject. ** DEGREE-HOURS'* Two methods have been adopted to indicate the quantitative relationship between rise in temperature of the air and that of thetree. Figure 4 is a tracing of the lower portion of a typical graph-record in which LM represents the hour at which the air- temperature line (T4) makes an intersection in the morning with the tree-center temperature line (Тн) during the daily rise in Тл. Тһе intersection point is A and is referred to as “Тл min." in the discussion and tables. DB represents the hour at which T4 reaches its maximum, and В is “Т, max.” E is the point at which Тн begins to rise and is “Тн min." AD is the temperature line on the chart through A. XF is the tem- perature line on the chart through E. CF equals ХЕ; and FG represents the hour-line through Е. G is taken as “Тн max.” The reasons for adopting these limitations have been partly indieated in the preceding section, and will be given in detail in further discussions. If the increases in temperatures were perfectly steady and Тл and Тн therefore straight lines, DB and FG would correctly indieate the increases and the ratio 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 171 DB/FG would be a measure of the net effect of air-temperature rise upon tree-temperature rise. For certain purposes it has seemed satisfactory to use this ratio as given in some of the following tables. However, since Тл апа Тн usually depart considerably from the straight line a more accurate method of estimation was adopted. Any area on the chart, as for example ABD or EFG, bounded by the tempera- ture record line and any given tempera- ture base line and within any given time limits, may be rather accurately deter- mined by counting the small rectangular врасев of the graph paper. The number of these spaces, divided by two, because each space represents 0.5? C., gives the ‘“degree-hours’’ for this area. Тһе ratio ABD/EFG is taken as a measure of the total net effect of atmospheric temperature change upon the tempera- ture change in the tree over the given Fig. 4. Method of de- 5 А termining the ‘‘degree- period of time. E T a t* GENERAL RESULTS As would be expected, there is always a ‘‘time-lag’’ between temperatures of the tree and those of the air. This occurs in a temperature change, as well as in the attaining of a maximum or of a minimum, and is greatest at the center of the tree. The length of this ‘‘lag’’ period is extremely variable, depending upon the interrelations of a number of factors. Since the phys- ical conditions in the tree and the environmental factors are so variable, the results of the investigation are best considered under three headings: (1) ‘‘low’’ temperatures, from about 10? C. downward; (2) ‘‘high’’ temperatures, from about 30° C. upward; and (3) ‘‘medium’’ temperatures, in the intermediate zone. Тһе limits of these three temperatures ranges are only very broadly placed, and under certain conditions the ‘‘me- dium"! range extends above or below the limits indicated. The (Vor. 26 172 ANNALS OF THE MISSOURI BOTANICAL GARDEN generalizations stated below are supported by selected ‘‘case studies"! given in detail later. LOW TEMPERATURES One of the outstanding tendencies during the colder portions of the year was for the tree temperatures to remain steadily at 0 to -1.5° C. for many hours while the air temperatures might be steadily dropping below freezing or rising above that point. Fluctuations between day and night air temperatures were often not reflected at all or only slightly in the tree tem- peratures, whereas a corresponding number of degrees of change at moderate temperatures directly affected the tree temperatures. Thus there was exhibited a buffer action which tended to prevent frequent changes in temperature across the freezing point. On the other hand, after 24-48 hours or more, if the air temperature continued to change in the same direc- tion, the tree temperatures began to follow the general course of the air temperature and eventually approximated any stead- ily maintained air temperature. HIGH TEMPERATURES During the summer of 1934, and especially the latter half of the month of July, high temperatures and low atmospheric humidities provided an exceptional opportunity to study the relationships of tree temperatures to high air temperatures in the absence of many of the usually complicating factors. When the air temperature rose to above 35° C. and there was a low relative humidity, the center temperature of the tree dropped contemporaneously over a variable period of time until an equilibrium was reached, after which it began to rise with the drop in the air temperature. On the hottest days, when the air temperature was 42.5? C., the center temperature was 27 to 27.5? eooler. On other days the center was 22 to 26? cooler than the air with a low varying from 15 to 17? C. If, during the day, the air temperature rose and fell more than once, the cen- ter temperature of the tree changed in the opposite directions immediately. The rate and amount of change were less than 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY liv those of the air but were in a definite ratio to the air changes. Frequently during July 18-25 a sudden rise or fall of even 1.5? in the air temperature produced an immediate drop or rise respectively іп the center temperature of 0.5? or more. The eambium temperature varied much less sharply than that of the center and air. It tended to rise in the morning with that of the air, but later attained an equilibrium between the air and the colder center temperatures. A subsequent slow rise, usu- ally eulminating about 5 hours after the beginning of the drop in the air temperature, varied slightly with the speed of change in the center and air temperatures. Thus, on July 19, 1934, at 4 p. m. when the air temperature (39.5? C.) began to drop, the center temperature was 17? C. while at 7 a. m. the next day it was 22? C. Here was a rise of 5? in 15 hours in the tree center occurring simultaneously with a drop in the air temperature of 13°. Тһе eambium meantime had changed only from 30.5 to 32.0? C. On July 20, from 5:30 p. m. to 2 a. m. the center tem- perature changed from 16.5 to 21? C. and the cambium rose from 31.5? to only 32.5? C. in 5.5 hours. The cambium temper- ature usually rose with the rise of the center temperature and against the drop in the air temperature, although concurrent with a rapid rise in air temperature there was at times a tem- perature increase in the cambium. From these observations it is clear that the temperature of the cambium region is a resultant of the cooling effect of the tree temperature acting against the absorption of heat from without. During the early morning of July 14 the rapid drop in the air temperature carried it below the two tree temperatures. During the same period the influence of the temperature of the air on that of the cambium is shown by the decline of the latter. As the temperature of the air began to climb, however, and that of the center began its daily drop, the cambium tempera- ture tended at first to follow the direction of the air but finally took the downward course of the center temperature. Тһе ef- fectiveness of this thermostatic action is seen in the records, for example, of July 21 and 22. Early in the morning the cam- bium temperature began to rise with, and to follow fairly [Vor. 26 174 ANNALS OF THE MISSOURI BOTANICAL GARDEN closely, the air temperature until the cooling effect of the cen- ter definitely pulled it down again in about three hours, even when the air temperature was still rapidly rising. At other seasons of the year the cambium was often at the same temper- ature as that of the air. It appears that there is only one adequate cause of the al- most instantaneous reduction of temperature of the center of the tree during the periods of high temperature increases. High air temperatures, both directly and through effecting a rapid decrease in relative humidity, set up an increased trans- piration which caused a certain water deficit in the tissues of the tree. This in turn resulted in a rapid interior vaporization of water which absorbed large amounts of heat, thus cooling the tissues. MEDIUM TEMPERATURES At moderate, steady temperatures, associated with other steady climatic conditions, the two temperatures of the tree, which ran close to those of the air, were almost identical, and their rise usually began very soon after that of the air. How- ever, the beginning of the decline in the cambial temperature was usually delayed 3-4 hours after the initiation of the fall in the air temperature, while that of the tree center was fre- quently delayed 1 to 2 hours longer, during which time the lat- ter even continued to rise. When there were gradual changes in the air temperature the changes in tree temperature kept расе, with only slight lag. When there was a more rapid and sharper change in the air temperature, as frequently in passing from night to day, the tree temperatures showed much less change. Thus differences between day and night air temper- atures of about 16? were reflected in corresponding tree tem- peratures by differences of only 2.5 to 3.5? (table 1). At times, even under moderate conditions, as on July 15, 1932, inereases in air temperatures resulted in slight, but defi- nite, slow reduction in the center temperature, thus exhibiting the thermostatic tendency; and at other times the cooling ac- tion is evidenced by an unusual wide spread between the air- 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 19 TABLE I Date Air А Cambium Е Center E 1934 temp. p temp. Tue temp. в Мау 27-28 | High 27 12 m. 20.5 8p.m 19.5 9 p. m. Low 11 4-5 a. m. 17.0 T 8 HL 16.5 8-9 a. m. Diff. 16 3.5 3.0 28-29 | High29.5 |12 т.-4р. т. 22.0 8-10 р. m. 20.5 |10-12 p. m. Low 13.0 ба. m. 18.5 7а. т 18.0 8 a. т. Diff. 16.5 3.5 2.5 and the tree-temperature lines. However, at moderate temper- atures this tendency was often obscured by other factors. When the air temperature was between 20 and 30° C. the cambial temperature kept close to it. During periods of slight, slow changes of air temperatures, cambial temperatures were often maintained 0.5 to 1.5° above those of the tree center, re- gardless of whether the air temperature was above or below that of the tree center. This might seem to indicate a tendency for the cambium region to maintain its own temperature some- what independent of the influence of the air and center temper- atures. We may conclude that, at or near the critical temperatures of freezing and of heat injury to protoplasm, living cells of the tree trunk are partially protected through special physical ad- justments. These physical adjustments, during high temper- ature periods, are dependent upon the excessive transpiration often induced by heat. Hence during such periods not associ- ated with excessive transpiration the tree might not exhibit the physical adjustments indicated above; and under high trans- pirational conditions, induced by other factors than excessive temperatures, an increased internal vaporization might be induced. DETAILED STUDY OF SPECIFIC PERIODS LOW TEMPERATURES The temperature of the cambium layer is mainly influenced by that of the air, but it is evident that in the changing climatic [Vor. 26 176 ANNALS OF THE MISSOURI BOTANICAL GARDEN conditions of the area in which these studies were made the cambium layer and the air are seldom at the same temperature. When the temperature of the air is on the decline that of the tree center is usually higher than that of the air, while with the air temperature rising the tree center is soon colder than the air. This relatively warm or cold center slows down the up- ward and the downward tendencies of the cambium temper- ature in response to the rise and fall of the air temperature respectively. This was particularly evident when the air tem- perature line erossed the zero temperature line in eontinuous upward or downward swings following a steady period below or above zero. After an adjustment in the tree had been made at about the zero line the temperatures followed the direetion of the air temperature with relatively slight lag in time but did not usually reach the extremes of the air temperature until the latter had become steady for several hours. These conditions, as well as the usual buffering action at the freezing point, are well illustrated by the following typical examples. 1. The tendency for the temperatures of the tree to follow closely those of the air after the tree had become adjusted to freezing weather is shown by the cold spell in the early part of March, 1932. From March 8 to 12, the tree temperatures closely paralleled those of the air which varied most of the time from —8.0 to -10.0° С. Also, during the night of March 12-13, 1932, the air temperature dropped from -3.59 to —9.5? C., and in an essentially coincidental drop the tree-center temperature reached –8.59 C. an hour later. This period had been preceded by 36 hours of sub-freezing temperatures in the tree, the cam- bium having attained a minimum of —4.0? C. and the center -4.759 C. The following specific examples illustrate well the usual buf- fering action at the zero line, by which the tree temperatures are held steadily at or close to zero for many hours or by which the cooling of the tree tissues is considerably slowed down. 2. At 11:00 p. m., November 14, 1932, the air temperature dropped from 14.0 to 9.09 C. in 0.5 hour, followed by a slower almost uniform drop to -8.0° C. at 6:30 а. m., November 16, or 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 177 a total drop of 22.0? in about 32 hours. Тһе cambium and center lines began their drops in 0.5 and 1.5 hours respectively, and after 2.5 hours they were essentially superimposed. Тһе cen- ter temperature reached zero at about 10:00 p. m., November 15, 23 hours after the beginning of the cold spell and 11 hours after the air temperature crossed the zero line. It then very slowly dropped in 8 hours, November 15-16, approximately 1.0? more, while the air temperature dropped from -5.0 to —8.0? C., giving a ratio of air temperature drop to tree temper- ature drop of 3:1. During the night of November 17 and 18 the air temperature dropped from -0.25 to —6.0? C. in 10 hours, while the tree center dropped only from 0.25 to 0.509 C. in that time. This gives a ratio of 23:1. On November 19 a 4.0? air- temperature drop resulted in a 0.5? drop in the tree center, or a ratio of 8:1. From 9:00 p. m., November 15, for more than 6.5 days, the cambium temperature was about a degree higher than that of the center, while neither showed more than a slight variation up or down. Meantime, the air temperature was mainly somewhat below zero, but with short, upward turns to about 45.0? C. on November 17 and 18, and 16.0? on November 20. Finally, on November 22, following a 12-hour rise in air temperature to about 8.0-10.09 C., the cambium, at 3:00 p. m., and the center, at 10:00 p. m., began their periods of rise. This ease history demonstrates the tendency for the tree temper- atures to remain at about zero even when the air temperature alternated from -8.0 to +16.0° C. It also shows, under an es- sentially constant zero tree temperature, the tendency for the temperature of the cambium to remain slightly higher than that of the center, even when that of the air is mainly below both tree temperatures. 3. At about 4 :30 p. m., December 6, 1932, a sharp drop in air temperature from about 20.0 to 5.0? C., followed by a slower decline to a minimum of –10.009 C., initiated an 11-day period of sub-zero weather, mostly between —5.00? and -10.00% C. Dur- ing the first 28 hours after the center temperature reached zero the cambium remained about 0.5? above the center tempera- ture, with the cambium attaining and holding a temperature of (Vou. 26 178 ANNALS OF THE MISSOURI BOTANICAL GARDEN -0.59 C. Then the cambium line gradually erossed the center line at about –1.259 C., and for more than 24 hours the cambium temperature remained about 0.5? lower than the center, while both temperatures were dropping to approximately —5.0? C. This case illustrates the usual tendency, under these condi- tions, for the cambium to hold a temperature during day and night slightly higher than that of the center while both re- mained at about zero. It shows also the tendency for the cam- bium subsequently to respond somewhat more rapidly than the center, as it does at more moderate temperatures, to the further changes in the air temperature. During the long cold spell fol- lowing the above initial drop in temperature the air temper- ature, on December 7 and 8, fell from —5.0? to —9.75? C., while the tree center fell from 0.0? to 11.25? C., a ratio of 3.8:1. Dur- ing the next two days a drop in air temperature from —3.5 to —10.00° C. brought about a drop in the tree center from -1.0 to —1.75? C., a ratio of 8.6 :1, while from December 9 to 10 an air- temperature drop from -7.5 to —9.5? C. caused a tree-center drop from —3.0 to —5.00? C., a ratio of 1:1. This shows that after the tree had been at a sub-freezing temperature for an extended period, in this case approximately 45 hours, a degree of air- temperature reduction was much more effective in lowering the tree temperature than when the tree had been only for a short time at the sub-zero temperature. This greater effectiveness of a change after a long period of sub-zero air temperatures is shown in a further drop in temperature beginning about 7 p. m., on December 11, 1952. In 12 hours the air temperature dropped from —2.75° to –15.50° C. Correspondingly the tree center dropped from -3.75° to –11.25° C., a total of 7.509, giving a ratio of 1.7:1.0. Тһе tree tissues had constantly been at sub- zero temperatures from the morning of December 8. 4. From December 19 to 22, 1932, the tree center held steadily at —0.5? to —1.5? C., with the cambium usually about 1 degree higher, although at one time the air temperature was above zero for more than 24 hours with a maximum at 11.5? С, Finally, on December 22 to 23, a rise in air temperature to +14.0° C. caused a slow rise in the tree temperatures almost to 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 179 that of the air, with the cambium temperature at the time of the air maximum 1 or 2? higher than that of the center. On the downward swings of the curves between December 7 and 22 the cambium- and center-temperature lines soon (3-4 hrs.) became superimposed, when the air temperature change was 5-8? C. in 12 hours; or the cambium assumed a temperature slightly be- low that of the center when more rapid or extensive depres- sions of the air temperature occurred. 9. From about 3:30 p. m., March 9, 1934, for 60 hours there was a zero to sub-zero air temperature reaching —12.0° C. in a continuous drop from zero іп 14 hours. Twice it rose to «1.5? C. for an hour or less, but otherwise it was mostly zero to —4.5? C. During all of this period the center tree temperatures were from —1.50? to 1.75? C., and the cambium about -0.5° C., except at the coldest period when it was -1.0? C. For the total period the ratio of Тл drop to Тн drop was 4.7 :1. 6. Тһе period of 34 hours, from March 18 to 19, 1934, with an air temperature minimum of —10.25° C., gave rise to a steady tree-center temperature of —0.5 to –2.09 C. for about 35 hours, beginning about 8 p. m., on March 18. During the initial change ТА dropped from 16.0? to –4.59 С.) while Тн dropped from 16.5? to 1.0°, ога ratio of 1.3:1. During the second significant lower- ing of temperature T4 dropped from -1.0 to -9.5? C., while Тн dropped from 0.259 to —2.0? C., or a ratio of 3.7 :1. In this case, approximately three times as many degrees of change in air temperature were necessary to cause one degree change in the tree temperature at or immediatly below zero as above it. 7. On March 5, 1932, at 3:30 a. m., there was a sharp drop in air temperature from 5.50 to 211.25? C., in about 28 hours. The tree-center temperature began to drop about 1.5 hours later, and the cambium in 0.5 hour. Thus there was а ‘‘lag’’ of only 1.5 hours in the beginning of the response of the center temper- ature to the change in air temperature. At this season of the year there is little or no heat used in the vaporization of water in the tissues, and at this time of day no direct insolation to complieate the situation. At temperatures above 0.0? C. the complications of freezing action are also absent. This is ap- [Vor. 26 180 ANNALS OF THE MISSOURI BOTANICAL GARDEN parently a good example of ‘‘lag,’’ due simply to the rate of heat transfer through the tissues. For over 56 hours the air temperature remained at —4.0 to -11.59 C., and for about 28 hours from the time that the tree temperatures reached 0.0? C. they held between that point and -1.25° C. For about 10 hours after the tree temperatures had reached zero they declined further only when the air temperature decreased again. For example, when the air temperature remained at -7.00 to ~7.25° C. for 6.5 hours (7 :30 p. m. to 2:00 a. m.), the tree center remained at -1.0° about 8 hours. Following the further drop in air temperature, the tree temperature began to drop slightly, and minor fluctuations continued in accord with those of the air. There was then a period of several hours of adjustment, near the zero line. Later, when the air temperature remained steadily at —11.0° C. and even after it began to rise, the tree temperature continued to fall for at least 6 hours. In this pe- riod the tree-temperature reaction was similar to that under moderate temperatures. During the first decline in air temper- ature the tree center dropped 6.25°, while the air temperature made its drop of 16.75?. This gave a ratio of T4 to Тн of 2.6 :1. During the second period of decline the ratio for the last 12 hours was about 1.3:1, which indicates that the zero-line adjust- ment had almost been completed in the preceding 32 hours. 8. On January 29, 1932, a sub-freezing period of 3 days with minima at —11.5 and -9.0? C. began. А steady drop in air tem- perature from 5.0 to 11.5? C. carried the tree center from 9.5 to 1.0? C. Тһе ratio for this period above zero in the tree was 1.05:1. While the tree temperature was erossing the zero line from 1.0 to —1.50? C. the air temperature dropped from -4.0 to -11.5? C., which gave a ratio of Тл change to Тн change of 3:1. During this time the tree temperatures remained steadily at 0.0 to -2.0° C. and continued so 24 hours longer in spite of almost continuous air temperature of 5.0? C. during this latter period. The cambium temperature then began a slow rise to a maximum of 2.5? C., with an air maximum of 9.5? C. Mean- while the center temperature remained steadily at —1.0? C. for another 4 days despite air temperatures for several hours from 5.0 to 13.0? С. on the last of these days. 1939] REYNOLDS— TREE TEMPERATURE AND THERMOSTASY 181 9. Тһе tendency for the tree temperatures to hold at or near 0.0° C. during frequent and sometimes rather extensive up- ward and downward changes of air temperature is further shown in the record of November and December, 1932. For ex- ample, from November 16 to 22 the tree temperature was es- sentially unchanged, while the air temperature shifted from -7.09 C. at night to 410.0? and once to +16.0° C. in the daytime. During this period the cambium temperature continued almost uniformly at 40.5? C., and the center at about –0.5 C. 10. From noon, January 12 to midnight, January 13, 1931, the center temperature remained at 0.0 to -0.59 C., and then slowly fell to -3.0° C. at noon the next day. It rose again in 12 hours to -1.0° C., and then for 3.5 days remained at -1.0 to 0.0° C. in spite of continuous air temperatures of 13.0 to 6.0° C. In this and two succeeding cases there is especially demon- strated the slow reaction of the tree temperatures at the zero line when the air temperature passes above zero after having been for some time below the freezing point. 11. Following the sub-zero period ending February 28, 1934, the air temperature rose and remained above zero almost all of the time for 80 hours, for 68 hours varying from about +3.5 to +10.0° C. During the entire period the center temperature held steadily at –1.5 to -0.5° C. and finally zero. The cambium stood at zero for 44 hours, with a gradual rise above that point for the rest of the time. 12. That the tree resisted temperature change when it had been at a steady sub-freezing temperature was shown on March 12, 1934. An air-temperature rise to 18.0? C. gave a total of 90 **degree-hours,"' while only in the latter part of this pe- riod the tree center had a 3 ‘‘degree-hour’”’ rise, or a ratio of 30:1. This contrasts sharply with the degree-hour ratios for periods of moderate temperatures as shown elsewhere. 13. About 9 a. m., January 28, 1934, the air temperature dropped steadily from about 10.0 to —16.5? C., a total of 26.5? in about 24 hours. When the air temperature was -14.0? C., the superimposed tree temperature lines were carried across the zero line without any apparent retardation in rate of fall. Fol- lowing a rise of a few degrees there was a second period of de- [Vor. 26 182 ANNALS OF THE MISSOURI BOTANICAL GARDEN cline in temperature, during which that of the air was 7.75? C., and of the tree center 5.0? C. This shows a ratio of 1.55 11. Dis ing the first period of decline the tree center dropped 12.0? in response to the 26.5? of the air, or a ratio of 2.2:1. сән although no visual retardation occurred at the zero line it is evident that during the first period a 2.2? change in air temper- ature was necessary to cause a 1? change in the tree, while dur- ing the entire second period after the internal adjustments had been made, only 1.55? of change in the air temperature was needed to eause 1? change in the tree temperature. This latter value agrees very well with the cases cited for periods of tem- perature change after the zero line adjustments had mainly been made. During the second period a change in speed of drop in the tree temperature occurred at about 10 p. m., January 29, although no change in speed for the air-temperature drop is evident. From that point to the end of the period the ratio be- tween the two temperature declines was 1:1. Since this oc- curred during the night when there were no complicating condi- tions, it demonstrates that the theoretieal value for this rela- tionship may be actually reached when there are no restraining influences. The attainment of this value also emphasized clearly the retarding influence of the zero line on the decline in tree temperatures, during the first period, when the ratio was 2.2 :1. HIGH TEMPERATURES The marked, thermostatic response of tree temperatures to changes in air temperature during periods of extreme heat was first noted in the records for the latter portion of July, 1934, although records of other years give the same indications in a less extreme form. Тһе graph-records for the period of July 15 to 26 reveal the principal fact that with every morning ad- vance in air temperature there was usually an immediate de- erease in the tree temperatures and with each afternoon de- crease in air temperature there was a corresponding immedi- ate inerease in the tree temperatures. For the whole period, table іп lists the data which show that for 2.48? rise in air temperature there was a 1.00? lowering of the temperature of 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 183 the tree center and for each 2.83? drop in the air temperature there was a 1.00? rise in the tree-center temperature. It should be noted that, in view of the cause of this phenomenon as indi- cated later, these ratios represent maximum values, since a more complete insulation would have more successfully pre- vented heat interchange with the environment, and it would have taken a smaller change in air temperature to effect a de- gree change in the tree temperature. Also it should be noted, as indicated in table п, that throughout this period the tree temperatures averaged much below those of the air, and that, in contrast to periods of moderate temperatures they were seldom directly influenced by fluctuations in the external tem- perature. TABLE II MAXIMUM EXTREMES Diff. Diff. 1934 | Tree eenter| Т, max, and Air T, max. and Cambium July Тн min. Тн min. T, шах. Те min. Тос min. 20 16,5% C. 26.0? 49.5? C. 2:0? 85 to 325° U. 21 16.5? C. 23.5? 40.0? С. 9.0? 810 to 82.0? С. 22 16.0? C 23.55 39.5° С. 8.5° 31.0 № 32.0° С. 23 15.0° С. 27.59 49,5% С. 11.0? 31.5 to 39.5” C. 24 15.0? C. 27.5? 49,5% С. 10.5? 82.0 :%0:88.0% -C. 95 15,5% С 27.0? 42.5? C. 10.5? 82:0 to 3957 С. During the day throughout this period the line registering the cambium temperatures was always between the other two lines and usually about 10? below that of the air temperature. This shows that some influence antagonistic to the heating ac- tion of the atmospheric temperature was at work. The chart indicates clearly that the cold central zone provided this influ- епсе. Radiation of heat from the cambium zone inward kept this zone from attaining the temperature of the ambient air and its temperature therefore was a resultant of the heat from without and the cold from within. Had this tissue been located midway between the center and the outside it would be expected that its temperature would have approximated the average of the air and center temperatures. However, when, as on July [Vor. 26 184 ANNALS OF THE MISSOURI BOTANICAL GARDEN 15, 18, and 20-25, the maximum air temperature of 38-42? C. continued for from 4 to 6 hours the cambium-layer temperature would be expected to rise rapidly due to eontinued absorption of heat from the outside. Nevertheless, during this period, be- eause of the counter cooling action of the central cold zone, it usually remained almost constant, or with only a slight in- erease. During certain other portions of the year in such a pe- riod of uniform air temperature when the various other Ғас- tors were steady the cambium temperature closely approxi- mated that of the air. Two main factors thus were concerned in determining the temperature of the tree at this time of year. 'The first was the flow of heat from high to low, that is during the day from the environment inward ; and the second was the active withdrawal of heat from the tree tissues. This latter action, as amply demonstrated in the records, increased and decreased directly with the increasing and decreasing air temperature, and its cause must then be associated with some reaction of the plant to temperature changes. The relative intensity of these two faetors determined the exact temperature attained in the tree. With an increase in the air temperature the cooling action in- ereased faster than the transfer of heat inward from the en- vironment, while during a decrease in the air temperature the transfer of heat inward exceeded the cooling action. Early in the day the cambium attained an approximate balance between the two faetors and later a balance was also reached in the tree center, resulting in a longer or shorter period of an approxi- mately steady, low temperature. The application of these prin- ciples accounts for the details of a typical record such as that of the following. From 9:00 p. m., July 13, 1934, the usual steady decline in air temperature continued until 1:30 a. m. on July 14, when there was a sharp drop of 9.5? in the air temperature which ended at 6:00 a. m. Meanwhile the center temperature, coincident with the slow decline in air temperature, continued its slow rise of the night period until 1:30 a. m., at the rate of 1.25? in 4.5 hours. From 1:30 a. m. until about 4:15 a. m. it rose 1,259, thus 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 185 increasing the rate to 1.25? C. in 2.75 hours coincident with that of air-temperature decline. This immediate, inverse relation- ship is also visually shown by the fact that at exactly 1:30 a. m., when the air temperature began its sharp decline, there was a very slight but definite upward movement in the record of the tree-center temperature. From 4:30 to 6:00 a. m. the cen- ter temperature remained steadily at 24.75? C., when it be- ean its drop in response to the rise in the air temperature. This record of the center temperature, like that of the cam- bium, indicates the compound character of the tree temper- ature. At first the heat added to the system, including the flow inward from the outer tissues, exceeded that absorbed through the internal cooling, and the tree temperature rose. From 4:30 a. m., for 2.75 hours, the transfer of heat inward and the cooling effect balanced one another, causing the leveling of the center-temperature line. At 6:00 a. m. the cooling action be- gan to increase, coincidental with the beginning of the rise іп air temperature, and became greater than the inward flow of heat. Therefore the center-temperature line shows the begin- ning of the daily decline which eulminated at about 3:45 p. m. and which caused a drop from 24.75? to 18.00? C., or a total decline of 6.75°, while the air temperature was rising from 22.00 to 36.00? C., or а total of 14°. From 3.45 p. m. until about 6:15 p. m. slight but definite fluctuations in the air temperature were inversely reflected in the center temperature. From then on the regular nightly drop in the air temperature was reflected in the rise of temperature in the center of the tree. During the next 12 days there were similar conditions, often in intensified form, which may be seen in the graph-records and in table іп. Тһе tree-center maximum (Тн max.) and the air-temperature minimum (ТА min.) usually occurred at the same time in the early morning, and the tree-center minimum (Тн min.) and the air-temperature maximum (ТА max.) at the same time in the afternoon. However, the maxima and minima often covered considerable periods of time, and for tabulation purposes it was necessary to select some certain point in each of these periods. Because of the instantaneous response of the [Vor. 26 186 ANNALS OF THE MISSOURI BOTANICAL GARDEN tree to changes during the high-temperature period the point of beginning of the air-temperature rise was assumed to mark the point in the tree-temperature maximum when the morning air-temperature rise began to influence the tree temperature. This point then was used as Тн max. and Та min. The other maximum and minimum points were selected by the application of the same general principle. From tables ш and ту it can be e | | Fig. 5. Бекет method of calculating ‘“degree-hours’’ for high-temperature perio O is the T, line; FHK the T, line; C, the , the 7 a. m. li he 3: .m line, and KO at 5:15 a. m., July 21. The posi- >“ of IE M p by the sg wpm of the decline 1 c Р 1 И п ВАО. taken as the area representing J the total eng in punt -hours’’ “aa ring the air- hes erg rise, and FHIG the ae н т д mber of ‘‘degree-hours’’ E: tempera de- erease at the tree center. Area PEO ud the total ' or -hour?? даба | in air temperature to the 5:15 a. line, and JIK the corresponding "degree Алези of temperature rise at the tree center Fig. 5 seen that the average ratio Тл change/ Тн change was about 2.5 and hence 2.5° change in air temperature caused 1.0° reverse change in the tree center. The method of determining the ‘‘degree-hours’’ for this pe- riod is analogous to that in fig. 4, and is shown in fig. 5, which is a direct tracing of the record for July 20, 1934. There are two possible explanations of the type of curve found in the record throughout most of July, 1934. The alter- 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 187 nating upward and downward movements of the lines might be due to an essentially regular ‘‘lag’’ period of twelve hours, by which the low tree temperatures of one daylight period TABLE III COMPARISON OF a ee OF RISE AND FALL OF AIR TEMPERATURE TREE TEMPERATURE Period of air-temperature rise (a) (b) (d) (e) (f) (g) 1934 Тн шах.” | Та min.t | Ty change | T, min.# | T, max.$ | T, change uly 14 23.75** 18.25 5.50 23.75** 34.75 11.00 15 22.00 18.25 3.75 25.75 38.50 12.75 16 28.25 19.50 9.75 26.00 37.50 11.50 17 21.75 17.75 4.00 22.75 32.75 10.00 181 21.00 15.75 5.25 25.75 37.50 11.75 19 21.50 17.25 4.25 26.75 38.75 12.00 20 22.25 17.00 5.25 28.75 42.00 13.25 21 21.50 17.25 4.25 27.25 39.25 12.00 28 21.50 17.6 4.00 27.25 38.50 11.25 23 21.50 14.75|| 6.75 25.00 36.50 11.50 24 21.50 15.0 6.50 29.00 42.00 13.00 25 20.50 16.25 4.25 29.50 41.50 12.00 26 20.00 19.00 1.00 27.25 30.25 3.00 Total 58.50 145.003: Xx Period of air-temperature drop 14 22.507 18.50 4.00 27.2511 37.00 9.75 15 8.15 19.25 4.50 27.50 39.00 11.50 16 21.50 | 19,50 9,00 97,50 87.50 10.00 17 21.25 19.00 2.25 26.75 89.00 5.25 18 21.75 15.25 6.50 26.50 39.25 12.75 19 22.25 18.00 4.25 28.75 39.50 10.75 20 921.95 17.25 4.00 29.50 41.50 12.00 21 21.50 17.50 4.00 29.50 40.00 10.50 29 91.75 17.25 4.50 25.50 38.75 13.25 23 21.25 18.25 3.00 32.75 41.75 9.00 24 20.75 16.00 4.75 29.50 42.25 12.75 25 19.50 16.50 3.00 33.00 42.00 9.00 26 18.00 17.00 1.00 30.00 33.25 3.25 Total 47.75 129.75tt # Ta min. taken at the last low point — th § Ta max. taken at the first high point reached ** Тн max. and Ta min. taken y^ a. m. intersection of Т max e rapid rise in the air po A with by the air temperature in the a. Tn. , rise. sd Subsequent small changes in air temperature and inverse changes in tree tempera- for r drop”) taken at the beginning of the steady high tem- 1 . take the first point in the Тн 4 at which it reached es- sentially a ndr | E if not at the absolute T4 n HH ТА/Тн = 145.00/58.50 = 2.47 :1. 11 ТА/Тн = 129.75/47.15 = 2.71:1 (Vor. 26 188 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE IV HIGH-TEMPERATURE PERIOD. RATIO BETWEEN eoe од E AND TREE- Sie ey TEMPERATURE CHANGE IN "DEGREE- HOURS." THE DIVIDING LINE BETWEEN “UP” AND “DOWN BEGINNING POINT IN THE DECLINE OF AND RISE OF Тн 1084 Air temp. Tree temp. Ta Up T4 Down July Up Down | Down Up Тн Down Tu Up 74 2.1 34 2.4% 1 4 84 55 эчүе ae — E 4—15 7 14 35 14 1 77 2.5 67 8.27 18-19 77 67 31 21 — = — — =— 31 1 21 Д 72 2.8 26 21% 19-20 72 26 25 18 c - 2 —ÓnáÓ 25 1 12 1 91 2.6 33 2.04 20-21 91 33 35 16 = 2 == cu M жим 35 16 L 116 2.1 49 2.4 24-25 116 49 54 20 = @ эш = 12% 54 1 20 1 * ізі ТА min. өле Тн max. at intersection, 7:30 a. m.; 2nd Ta min. and Ta max., : In, 177 1 1st Ta min. and Тн max., ETE Mi 2nd T4 min . and Тн max., 3:15 a. т., 7/19 # ist Ta min. and Тн max., 6:30 a, ‚ and ТА min. and Тн max., "А 2% midnight. 1 ist Ta min. and Тн max., 7:00 a. A ; 2nd ТА min. and Тн max., | T/21. $ 1st Та min. and Тн max., 6:00 a. m. : 2nd ТА min. and Тн max., i 00 = etg 1/25. would be due to the declining air temperature of the preceding night. The only alternate explanation is that the low tree tem- peratures were due to a definite cooling concurrent with and related to the air-temperature rises of the daylight period. This latter is the hypothesis adopted in the earlier portion of this section. We will now consider the objections to the first of these alternate suggestions. First, in the earlier part of the year the apparent lags due to rate of heat conduction through the tree tissues were, at the longest, about 1.5 to 2.5 hours, and sharper changes of air tem- perature caused an evident response even within an hour. Moreover, a study of the records shows that immediately after the intersections of Тл with Тн in the morning and afternoon the temperature usually continued its decline or rise respec- tively for 0.5 to 1 hour before the change in direction of the Тн 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 189 line can be detected. Hence the 1.5- to 2.5-hour lag includes the time when the influence of the preceding temperature was still operating. Actually, then, this apparent lag is longer than the true lag due to the heat conduction rate of the tissue. Second, the records at various seasons of the year show that when there was a deep and long depression of the air temperature below and before the morning intersection of Ta with Тн, especially with a slow rise in air temperature above the intersection, the apparent lag in rise of the tree temperature might be pro- longed to 3 to 4 hours. With a shortening and decreasing of the eool period prior to the morning intersection of Тл and Тн the apparent lag period decreased. Therefore when there was no such depression below the tree temperatures, as during the latter part of July, 1934, there would be no apparent lag period and the cooling action would be immediately evident with rise of air temperature. Such was the condition during this hot spell of July, which is strong evidence also that the conditions recorded in the chart could not have been due to a 12-hour lag. Third, since the air temperatures during this entire period were, even at their lowest, higher than the highest point in the tree-center temperatures, a decline in the air temperature could not have lowered the tree-center temperature. Since the first explanation evidently cannot be accepted, the positive evi- dences in favor of the second alternative will be considered. In passing from the early portion of the year toward the high-temperature period the apparent morning lag in Тн ad- vanced from about 1.5 hours to about 3.5 hours (table v, column ‘‘d’’). This lengthening of the apparent lag period cannot be assumed to be due to an actual change in the heat conductance of the tissues and hence a change in the true lag. Moreover, since the tissues involved are identical for the vari- ous years listed, no important difference in conductivity can be due to tissue differences. Therefore, this difference in ap- parent lag period can only be accounted for on the assumption of a cooling of the tissues which counteracted to a greater or less extent the heat from the rise in the air temperature. Furthermore, the following study of the records of several [Vor. 26 190 ANNALS OF THE MISSOURI BOTANICAL GARDEN во 19 10 19 > © © _ 12 ој дејецомк~ 916% er 999 кек S as оччо о oon coor омоч о g авай БЕН 888 ЯЕЯЕЕ а 58 Ada Es & gg d. & dí du & e д дд Eslecece зоо occ onoce s = Sot ee em -- pens iie Sy o 00 са C1 r4 са oon ~ ~ > Ф ~ ~ 0 с = === rA n n = E. Е . . . . . LÀ LJ ы . . . . . . . . ^ ЖЕГЕ ЕЕЕ НЕЕ EEEE — е о 5 » 4 LE TE 4 . 22 s В іш Е шашағы Ба ка БА = Ба = Py Py я Бы . ооо юю о 2| |53|в888%5) (888) |353| |95589 = © Ф чо "ч oo > ~ o ж E Б === © e 4 T E о Ф Н a| eo |. соба > | eae месео z, = А5 | оі са ci cd ei e ci Aes eo сї сі о & Ё 5 ||*e rrr *» z| |. [88888 ЕЕЕ ЕЕЕ ЕНЕЕЕ P b == б а а а d dd & дд, d дд дд. М © „Б 32138838 825 |398 282822 Ф саса са = са Шо =ч orn aa — сеа > : lae жұға 4 "EUR „К RAR aS BER НЕЕ ЕНЕЕЕ “о MPHELEDLET: даа шаа далда с|сосюою e x <2 |28893 |388 588) |88888 в vonon oon t- m тч te 00 © Е [9] 2 т Ы кн 2 = |дгјујеегаче iow 19 мо м € V3 M» О и d ASIN a са со се saa са са & || „ 2 Ф м x ЕБЕБЯ ЯЕЯ БЕН ERRRE 5 == Баа ісе бе а dddcd ~ о (= Alo e © "| |88|88288 BRS 882 8585322 ^ -Toocc oon © Ф <> 2:00 © Q 2 ст ae 4 “аже "ap "MEIN PET. e БЕБНЕ БЕБЕ БЕН AA BASE Е х 8 асса за а ба «а баса ЕЕ ЕЕСЕРІЕРГСІСІ eco ooo ooooc = = |го> еф 52 65 & с вене ЈЕ собе t- t- 00 t- t- t- ~ t- 00 tO © bo Q ea тэ ~ — +H тэ es са% + са ь, а | 2 2 | то о ~ о | о д | о = ез | с >> e | "сео о’ | мамам | © SAA asl 00 шш 44616155 "іы a » | - | > МУ ~ w bh pc 1939] 191 REYNOLDS—TREE TEMPERATURE AND THERMOSTASY "әлоҙәд ULUI HL 03 ләзорә IL ЧИМ рие ӯр, ut эццоэр ‘ш 'd 993 [HUN 98H әріп MOUS 9 pue ет Ат # "алпувлод шој JI? әц JO э5м ‘ши 78 993 SULINP әлпуеләашәў ләҙиәо-әәлі ƏY} UI әвї JO YOR] ay} Аа peoouopiAe SEM попов Зицооо оушцор зојер әвәці лэзуе рие 910geg 72661 FT-OT 9unf имоц$ SEA рлооәл JO әй} JUELS оц t "әлпјеләйашәј ліе UL эзы BY} JO Pee oy} Ајојојашоо ezi[e1jnou 0} juerogjns SVA UOL Зипооо sy} eur YOM Aq “ш ‘А eu) ur эиПоэр 03 uesoq әлпуеләйшәзў ie оца 1933? [NUN әвім зои рур әлпуеләйшәзў ләҙиәо-әәлі IUJ 65 AINE ЧО fry uuin[oo ur ҙиәҙхә 94105 03 pue 4, put D. suuin[0o ui UMOYS ве 'sporred „ILL, eu) SuiseaJ9UI UI QU9DIA9 SEM иопов Зицооо 9[Q.I9pISUOO е *0eer ‘Aine jo Hed 193381 eu? 3urinq $ ПЕ: рие әзіл әлпувләйшәў-де jo Sutuulseq 993 ‚.‘5роцзэй,, uo uorjoes ор, рие HY, цам VL JO uonoes19jur IYJ 3€ uox) st оца JO $ рив 2 ‘SON лорип рэзеотрит SAd pud 94} SurMO[[O,T s 090 "ur'd 00:2 | "ш ‘d 02:9 042 эш ‘d 00:01 | "м ‘d 08:2 eT "ut 00:21 |°ш ‘е 06:0Т 05 35'0 u ‘d 00:9 |'ur'd cpg ecc ‘ud 08:8 [ш ‘d ст:9 ет эш се (6:6 [ш ‘е 00:8 6t 00'T эш ‘d ep:g [uw cd ст: ест "ш 'd 00:11 | "м ‘d сў:6 CLT "ш € 06:6 [ "ш € 87:1 8T VORES NE (вевт) от "ш '4 08:9 (сш '4 og:¢ 0072 "ш `4 08:8 |'u 'd 08:9 “т ча 7% 06:07 |"ш ^e 00:6 gI от эш а 08:2 |'ur'd 08:9 ест эш ‘d 02:6 |'u ‘d ст:8 e "ш се 00:6 |W ‘Be 02:8 от 35'0 эш ° от: |°ш 'd 00:2 0072 "а "4 08:6 |" 'd 08:2 от "uri? 00:8 |°ш 7% 00:4 6 с270 “ш 4 op:g |*щ 'd 00:6 007 эш `4 00:9 |'ut 'd 00:8 от "ur? 05:8 [ш * 08:1 Ӯ 09'0 эш ‘d 08:2 | "ш 'd 90:4 0€T "ur'd 08:6 |7474 00:8 0% "ur? CT: OT |W ^e ст:8 е 090 "u `4 og: or | "ш ‘d 00:01 OST эш в OEIT |°ш 'd 00:21 “т "осе 08:8 |'u се 00:4 2 00'T ‘u ‘d 00:8 jvm ‘d 00:2 ест ш 74 08:6 |" ‘d ст: 8'5 "ur? 02:8 |°ш 00:9 I аду (ғевт) (Vor. 26 192 ANNALS OF THE MISSOURI BOTANICAL GARDEN specifie cases will give clear evidence of the validity of the con- cept of a positive cooling action in the tissues, and the difficulty in accounting for the curves on the basis of a ‘ас? of several to 12 hours. In early June, 1934 (e.g., June 3, 4, 5, ete.), the maximum temperature of the cambium was reached approximately 2 hours before that of the center, while the air temperature was falling, sometimes even below the tree temperatures, as on June 5 at 12:00–5 :30 a. m. Тһе high air temperature preced- ing the high tree temperature was at about 1:30 p. m., the day before, with a secondary high at 4:30—5 :30 p. m. (30° C.), or in other words 10 to 12 hours before. This rise of the tree temper- ature, both center and cambium, could not be ascribed to "lag" due to slow conduction of heat from the outside, because of the great length of time. Therefore it must be ascribed to an actual warming up of the inner tissues due to the slow removal of the cooling action. The records show that on May 13 and 14, 1932, there was a period of 1.5 to 2 hours from the morning intersection of T4 with Тн to the beginning of the rise in Тн, while on May 15 there was no rise at all until the afternoon decline in T4 began. The 1.5- to 2-hour period is the usual interim, which represents the maximum true lag in the beginning of the reaction of the tree- center temperature to a change in air temperature. The lack of such a lag period on May 15 indicates that the cooling action within the tree was sufficient to counteraet the incoming heat. In other words, due to the cooling action, the 43 ** degree- hours" change of the atmosphere was unable to raise the tem- perature at the center of the tree. On May 14 a 12? rise in the air temperature caused a rise of only two degrees at the tree center while on May 15 a 15.5? rise failed to change the tree- center temperature. During the night of June 3-4, 1932, the tree-temperature lines and that of the air were superimposed for about 13 hours, and about 5 a. m. the air temperature began a slow rise. At about 8 a. m. the tree-center temperature began to rise, and a total rise of 10.00? in the air temperature resulted in a 1.25? 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 193 rise in the tree center. During the next several days the tree- center temperature showed no rise except in association with the afternoon decreases in the air temperature. Here again on the first of these days the cooling action was not quite sufficient to neutralize the heat which penetrated from the atmosphere, while on the several following days it was sufficient. Тһе гес- ords for July 13, 14, and 15, 1932, are typical of a large number of those for that month, which show that the cooling action was sufficient to prevent any heating of the tree center. During most of this period the cambium temperature was held at 1 to 2? above the center temperature, with little evidence of being influenced by the air temperature. This condition contrasts with that in March and April, as, for example, April 29, 1934, where the cambium temperature was influenced much more by that of the air and averaged 3? or more above that of the tree center. Even at this time, however, there was probably a con- siderable cooling action, since a few days later, by May 3 and 4, there was only a slight rise of temperature in the tree center. The record of March 19, 1932, illustrates the relationship of the three lines when little affected by the cooling action within the tree. Here there was an average difference between the Тн and Тс lines of about 4°, and the Тс line was almost in mid- position between the Тн and ТА lines. А comparison of the spread of the three temperature lines during the latter part of June and the month of July, 1934, (table v1) shows that in general while the distance between the air-temperature and the tree-center-temperature lines (Ta max. minus Тн min.) inereased greatly with the hotter weather, the distanee between the air-temperature and the cambium- temperature lines (Тл max. minus То) averaged about the same throughout the whole period. Since, moreover, the dis- tance between the two tree temperature lines (Tc minus Тн min.) inereased greatly, the cooling action must have increased much more at the center than at the cambium. That the center cold zone was somewhat more effective in cooling the cambium at high temperatures than at lower ones is shown by the fact that there was a greater increase in the air temperature from 194 ANNALS OF THE MISSOURI BOTANICAL GARDEN [Vor. 26 the early part of the period to the latter part than there was in the cambium temperature. TABLE VI Тн MIN., Ta MAX., AND Tc AVERAGE, JUNE AND JULY, 1934* Diff. (1934) | a max Diff Diff June Ty min. T, max, | То average and Т, max Tof and Тн min and То mi 19** 19.5-21.5 31.75 20.00—24.00 11.25 9.75 1.5 20** 21.5-23.0 33.50 22.50-25.25 11.25 10.25 2.0 21 23.25 33.00 25.00 9.75 8.00 1.75 22 23.25 34.00 25.00 10.75 9.00 1.75 23 24.75-25.25 37.00 26.25 12.00 10.75 1.25 24 25.00 36.00 27.00 11.00 9.00 2.00 25 24.50 35.75 26.50 11.35 9.25 2.00 26 25.00 36.25 27.00 11.25 9.25 2.00 27 25.50-25.75 37.75 27.15 12.00 10.00 2.004- 28 95.75 87.75 27.75 12.00 10.00 2.00 29 26.00 38.00 28.00 12.00 10.00 2.00 30 irregular 26.25 July AF 21.50 33.50 25.00 12.00 8.50 3.50 2 20.75 36.00 26.00-27.25 15.25 9.50 5.75 3# 19.00 37.00 26.75-27.50 18.00 10.00 8.00 4 18.00 36.00 27.00-27.75 18.00 8.50 9.25 "B 18.00 6.50 28.00 18.50 8.50 10.00 6 19.50 29.00 irregular 27.00 9.50 2.00 7.50 7+ 17.75 1.00 26.00 13.25 5.00 8.25 8 17.25 31.50 25.75-26.75 14.25 6.25 9.00 9t 20.50 32.00 26.00-27.00 11.50 5.50 5.75 10 18.00 34.25 25.00-28.00 16.25 7.75 8.50 11 20.00 37.00 27.50—31.00 17.00 7.75 9,25 19 19,75 89,50 27.50—31.00 19.75 10.25 9.50 18 18.75 39.50 29.25—31.00 20.75 9.25 11.50 14 18.00 36.75 27.50-29.25 18.75 8.75 10.25 15 18.00 38.75 28.50-30.50 20.75 9.25 11.00 16 19.50 37.00 29.50-80.00 17.50 7.25 10.25 17 17.75 32.25 28.25 14.50 4.00 10.50 18 16.75 38.75 27.75-30.75 22.00 10.00 12.50 19 17.50 39.25 29.25-30.75 21.75 9.75 12.50 20 16.50 2.00 30.50-31.75 25.50 11.00 14.50 21 17.00 40.00 30.25—31.50 23.00 9.25 13.50 22 17.50 38.75 30.25—31.00 21.25 8.25 13.25 23 15.50 41.50 29.25—32.00 26.00 11.00 15.00 94 15.25 42.00 31.25—32.25 26.75 10.35 16.50 25 16.00 42.00 31.25-32.95 26.00 10.25 15.75 2 17.00 32.75 15.75 3.25 12.50 * In degrees centigra ** Both Тн and Tc = 1 Slight a. m. Intersection of Ta with Тн. 1 CL ms with ТА. # а. т. omes TS of Ta with Тн. 1 жылла values sometimes used for Tc. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 1095 On July 16, 1934, at 7:00-7:30 p. m., a sharp drop in the atmospherie temperature not only resulted in a sharp rise in the tree-center temperature but also in about a 0.5? temporary rise in the cambium temperature. This was immediately fol- lowed by a decline in the latter as the air temperature dropped. The immediate inverse response in the tree to air-temperature change definitely indicates the instantaneous nature of the thermostatic action. Often, even in minor fluctuations, this is shown in the records of the high temperature period (table уп). TABLE VII EXAMPLES OF MINOR, INVERSE REACTIONS TO TEMPERATURE CHANGES (1934) Air-temperature| Tree-temperature July Hour change changes Notes 14 9:30- |1.5° decline Cambium and center 10:00 a. m. rise 5:30- Slight rise Slight center drop 6:00 p. m. 15 1:30 p. m. |1.0? rise 1.0? drop 16 10:00- |8.57 rise 1.0? center drop Further air-tempera- 11:30 a. m. 0.5? cambium drop ture and center nge 17 4:00- |2.25° drop andj|About 0.5? rise and |Several further 6:00 a. m. then a. m. rise| then a. m. drop minor fluctu- tions 18 10:30- |6.5° rise 3.0? center drop persas — -— 11:30 a. m. and re sie questa 19 Several fluctua- |Several reverse re- i sponses in eenter 24 11:00- |Sharp inerease |Sharp drop 1.5? center 11:30 a. m. | in temp. rise 3:30- Sharp drop and |Sharp rise and drop in 4:30 p. m. rise center and slight ef- fect on cambium On each of these days also the beginnings of the rapid morn- ing rise of air temperature and of afternoon decline are associ- ated with immediate reverse changes in the tree temperatures, so that in general the Тн line is usually a mirror image of the Тл line. These examples not only clearly indicate the almost (VoL. 26 196 ANNALS OF THE MISSOURI BOTANICAL GARDEN instantaneous nature of the thermostatic action, but also give positive evidence that the active cooling of the tissues is a re- sponse to the air-temperature rise. After considering the various positive evidences just cited it can hardly be doubted but that thermostatic cooling is a major factor in determining the tree temperatures during the high-temperature periods of the year. Other phenomena as- sociated with the summer periods will now be considered. The morning sharp rise in the cambium temperature, during this period, which parallels that of the air temperature, may be due to either one of two factors or a combination of them. It may be assumed that in the morning a certain amount of direct insolation of the tree trunk might have taken place in spite of its being shaded by the heavy foliage. There are no direct ob- servations upon this point. On the other hand, it may be as- sumed that the sharp rise in air temperature generally caused the corresponding rise in the cambium temperature. It ap- pears from a tabulation that these sharp rises in the cambium temperature began essentially at the same time, about 7:30 each morning. Direct insolation could have been the cause, sinee the sun's rays would have been at the same angle each day over this short period of time. On the other hand, there was a direct relationship between the intersection point and the beginning of the rise in Тс, us- ually a 15-minute interval only, which coincides with the lag in cambium-temperature at other times in the day and other sea- sons of the year when direct insolation would be impossible. There is then no conclusive evidence on this point, although the ease next cited indicates direct insolation as a factor at this time of day. Тһе cambium temperature during the night of July 13-14, 1934, began a slow decline at about 11 p. m., which continued until about 4 a. m., when a 3? drop in 3.5 hours occurred, result- ing from an almost synchronous sharp drop in the air from 27.75 to 22.00? С. Incidentally it may be noted that there was a ‘‘lag’’ of about 15 minutes between the beginning of the sharp drop in the temperature of the air and the beginning of the 3? 1939] | REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 197 drop іп the cambium region. From 7:30 a. m. until about 10:15 a. m., this region remained steadily at about 28.25? C. Since both the air and center had lower temperatures the cam- bium should have continued to drop due to continued radiation of heat to them. That it did not do so is indicative that a source of heat sufficient to balance the radiation from the cambium must have been present. Direct insolation is thus suggested. It will be evident from the following discussion that thermo- stasy was not confined to the excessively hot dry period of late July іп 1934. An intermediate condition is shown on the record for July 14, 1934, when the air temperature dropped below that of the tree center for approximately 3 hours during the early morning. Except for this early morning drop, the record is essentially like those which followed it. The Тн line began to drop from 25.009 C. about 1.75 hours after the Тл line first crossed the Тн line, at which time the temperature of the air fell below that of the tree center. For about 1.25 hours the tree- center temperature dropped in response to the lower air tem- perature. Then the Ta line re-erossed the Тн line due to the daily rise in air temperature. After that the Тн line continued its downward соптве, but now the decreasing center tempera- ture was due mainly to the thermostatic action associated with the rising air temperature. That this decreasing tree tempera- ture is due to one factor in part of the curve and to another Ғас- tor in another part emphasizes both the necessity of a careful analysis of the records and one cause of misinterpretation of former records in which intermittent and partly correlated ob- servations were made. On July 2, 1934, about 5 a. m., the air temperature dropped somewhat below that of the tree center and under its influence the latter continued to decline. At 7 a. m. the air-temperature line re-erossed that of the center temperature, which continued to drop with a slight acceleration until 10 a. m. This decline may perhaps be considered as due to: (1) the ‘‘lag’’ in response to the former air-temperature decline, and (2) an acceleration of this drop due to thermostasy. That the latter is a real factor ean be seen from the further changes of the two temperatures. (Vor. 26 198 ANNALS OF THE MISSOURI BOTANICAL GARDEN From 9 to 10:30 a. m. the air temperature was almost steady, though with a drop of 1? during the last 0.75 hour. At about 10:30 the center line leveled out, thus showing that the flow of heat in from the heated air and out through the cooling ac- tion had attained a temporary equilibrium. When at 11:30 the air temperature began to rise again the center temperature responded by a slow decline of 0.50°, beginning about 0.5 hour later. А decline of air temperature of 2? in 1.5 hours, begin- ning at 1 p. m., was registered an hour later in the center by the beginning of a rise of nearly 0.59. Тһе air-temperature rise, starting at 2:30 p. m., was reflected in the center an hour later by the beginning of a decline of 1.25°. The final decline in air temperature for the day began at about 5:15 p. m., and the final rise of the center temperature began about an hour later. This analysis of the fluctuations in the day's records shows that there was a ‘аз’? of about one hour in the response of the tree center to air-temperature changes. It should be clearly under- stood that this type of ‘‘lag’’ is in no way similar to the ‘‘lag’’ which may be due to slow conduction of heat into or out of the tree. At a later stage in the water deficit in the tree (July 15- 30) there was essentially no lag in this internal thermostatic aetion. On July 26-28, 1930, the temperature reached a maximum each day of 39—41° C., following а long period of medium-high temperatures with maxima between 25 and 35? C. Тһе tree temperatures during the earlier period had varied plus or minus 1 to 2? around 25? C. During the 3-day period under consideration this variation had shifted to plus or minus 1 to 2? around 30? C., with the center during the maximum periods about 2? lower than the cambium. Two additional phenomena are especially notable during this period. First, when the air temperature was at its maximum, the center temperature was approximately 10? below it, and its own maximum was 7 or more degrees below the air maximum. Second, on the third day, which was the hottest, the center and cambium regions were both cooler than on the preceding day as evidenced in table уп. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 199 TABLE VIII Degree-hours be- (1930) Max.air | Tree-center | Tree-cambium| tween 30? line and July Time __| temperature |temperature| temperature | air-temperature line 26 3:00 p. m. | 38.75° C. 29.75° C. 31.50? C. 82 5:00 p. m. 32.00? C. 9:45 p. m. 31.25? C. 27 3:00 p. m. 40* C. 30* C 31.75° C. 95 5:30 p. m. 32.00-° C. | 11:00 p. m. 31.25? C. 28 3:30 p. m. 41% С. 29.75? C. 31.50* C. 103 5:30 p. m. 31.75? C. 11:00 p. m. 31.25? C. In addition, although the maximum air temperature on July 28 was 2.25? higher and there were 21 more ‘‘degree-hours’’ of change than on July 26, the tree temperatures were the same on both days. This indicates clearly that during the summer period of 1930 the same cooling action which was so sharply evident during the excessively hot dry spell of 1934 was effec- tive in keeping the tree temperatures well below those of the air. It should be noted again that since during periods of low to moderate air temperatures the tree-temperature graphs often are almost superimposed upon that of the air, at higher temperatures a great resistance is evidently offered by the tree tissues to increase of temperature. This cannot be due to slow conduction of heat through the tissues, since in this set of ob- servations the same set of tissues was involved throughout, and relatively rapid response, together with a temperature es- sentially equal to that of the air, was very frequent. The ‘‘lag’’ which has been heretofore ascribed to slow heat conduction and heat radiation is therefore due not only to these factors in part, but also to this thermostatic cooling of the tissues. During large portions of July and August, 1932, both tree temperatures held steadily between 25 and 30° C., with only slight movement up and down in response to the daily and nightly swings of 10° in the air temperature. This resistance by the tree to change of temperature during considerable [Vor. 26 200 ANNALS OF THE MISSOURI BOTANICAL GARDEN changes in air temperature may now definitely be ascribed to the thermostatic action and not mainly to ‘‘lag’’ induced by slow heat conduction. On July 29, 1930, the cooling effect on the tree temperatures is shown by the fact that, following the intersection of Ta with Тн and Тс during the morning rise of ТА, the line representing Тн dropped as Ta increased and the rise in То was postponed for 3 hours, until 12:30 p. m. During the preceding days it had varied only from 0.25 to 0.75 hour later than the intersection of Тл and То. For the entire period of July 23-28, 1930, an in- creased cooling action in the tree is evidenced by the increase of the difference between the tree-temperature maxima and the air-temperature maximum as seen in table тх. TABLE IX (1930) Diff. Diff. July T, шах. Тн max. T, and Ти Тс max. T, and Тс 23 31.50 26.25 5.95° 26.75 4.75 24 30.00 25.75 4.25? 26.00 4.00° 25 36.00 27.75 8.25° 28.75 7.25? 26 38.75 31.25 7.50? 81.75 7.00 27 40.00 31.00 9.00? 31.75 8,252 28 41.00— 81.25- 9.75? 31.75 9.25? 29 88.75 28.25 5.50? 29.00 4.75? For all of these periods, during which a definite thermostatic cooling can be demonstrated, the number of ‘‘degree-hours’’ of air-temperature rise required to cause one ‘‘degree-hour’’ rise in the tree center is indicated in table x. In general, it can be seen that the ratio rises from about 3:1, when the cooling action due to transpiration would be none or slight, to much higher ratios as the season advances until in certain cases little or no rise takes place in the tree in response to the rise in air temper- ature. The next step is the positive reduction of tree temper- ature during the air-temperature rises. The variability in the ratios may be accounted for by the action of other factors than air temperature as discussed in a later section. It is clear from the records just cited that the thermostatic cooling of the tree tissues is a phenomenon present at least dur- 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 201 ing the warm portions of the year and not simply under the ex- treme temperature conditions such as existed in the latter por- tion of July, 1934. TABLE X DEGREE-HOUR RATIOS АТ VARIOUS SEASONS OF THE YEAR * Ratio заг) ABD eh ABD EFG Era T, max. 15 83 29 2.8:1 15.50° C. 9 hrs. 16 42 16 2.6 :1 17.00? C. 2hrs 17 37 10 8.7:1 23.00? C. 2hrs 29 87 30 9,9:1 19.00? C. 2hrs 30 55 14 8.9:1 29.95? C. S8hrs April al 72 24 8:1 18.00° C. 5hrs 2 93 30 31:1 94.50? C. 3hrs 14 94 34 2.4:1 23.50? C. 2hrs 16 58 16 8.6:1 20.00? C. 2hrs 17 52 18 2.9:1 20.00? C. 3 hrs 18 69 25 8.7:1 26.50° С. 23 76 19 4.0 :1 27.00? C. 1.75 hrs 25 39 9 48:1 20.00? C. 27 21 7 8:1 15.00? C. 2hrs 28 51 1 3.4:1 18.50* С. 2 29 68 18 8.5:1 24.00? C. 1.5 hrs May 3 44 8 5.l:l 27.50? C. 2hrs 6t 66 9 731 29.00? C. 1ћг 71 81 40 1 40.0:1 29.50? C. 2hrs 9t 71 3 23.0:1 88.25? С. 9,5 hrs 19 53 10 5.3 21 98,259 C. 2hrs 16 66 16 4.1:1 24.00? C. 3hrs. 1 69 15 4.6:1 28.50? C. 1.5 hrs t 69 9 7.6:1 29.50? C. lh 19-22t 50 10 5:1 26.75^ 0. $ he 25 29 10 2.9:1 21.50? C. 1.5 hrs 26 58 15 8,8:1 28.75? С. 1.5 hea, 27 75 15 5.0:1 26.25? C. 4hrs. 28 129 23 5.6:1 29.25? C. 2.5 hrs 29 100 13 GRI 33.00? C. 2 hrs 301 814 June 8 * In calculating these areas the boundary of the tree temperature area was raised 1.5 hours to make up for the 1.5-hour “lag” approximately, which occurs in the € ation of the rise of the tres temperature after the intersection of the Ta with the Т line during the morning rise of T. 1.5 hours past the last point of air maximum taken as line FG. (See fig Shows inverse Eolo of Тн to Tain p. m. [Vor. 26 202 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE X— (Continued) (1932) pons T a max, June ABD EFG — EFG 18 45 5 9:1 13 28 4 7:1 14 16 1 16:1 15 33 4 8.2:1 16 59 6 10:1 17 63 7 9:1 29 63 10 0.331. July 14 55 2 97.5:1 15 56 3 18.7:1 (1930) uly 24 23 5 4.6:1 26 74 15 5:1 97 69 i 9.8:1 28 66 5 13.2:1 29 24 1 24:1 MEDIUM TEMPERATURES Many of the principles previously discussed are applicable to the medium range of temperatures, and some ‘саве studies”? in this range were necessarily considered in former sections of this paper. The demonstration of thermostasy in this temper- ature range is important as indicating that it is a general phe- nomenon which is one of the significant factors determining the tree temperatures. Evident cooling of both center and cambium tissues, associ- ated with air-temperature increases, shows clearly on the rec- ord of early July, 1934, when both failed to follow the upward trend of the air temperature and when the center temperature had even a slight downward trend. The thermostatic action is visually demonstrated in an especially striking manner on July 9, when at 2 p. m. a sharp drop in the air temperature of almost 9.0? was reflected immediately in a sharp rise of the center tem- perature of slightly over 0.5°. This contrasts sharply with the normal condition at periods of the year when foliage and there- fore active transpiration are absent. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 203 EARLY EVIDENCES OF THERMOSTASY IN 1934 Between 6:15 and 6:30 p. m., June 17, 1934, there was a sharp drop in the air temperature from 30.25 to 19.509 C. At the same time the center and the cambium temperatures took an upward trend, the latter somewhat more marked. This was followed by a general downward movement, the center beginning 1.5 hours after Ta crossed Тн, associated with the continued drop in the air temperature. Two things are shown at this date: (1) the direct and immediate dependence of a rise in the tree temper- atures on a drop in the air temperature, and hence the presence of a prior cooling action; and (2) an interval of only 1.5 hours between the intersection of the air line with the tree-center line and the beginning of the decline of the tree-center temperature. In the latter part of June, 1934, as, for example, June 26, a balance was evident between the transfer of heat inward and the heat removed by the cooling action. From 7 a. m. to 5 p. m. a temperature of 25? C. was steadily maintained in the center of the tree while the air temperature increased from 25? to 36.25? C. in six hours and remained at about that point for 4 hours. At 5 p. m. the air temperature began to drop and simul- taneously the tree-center temperature began to rise. This same reaction is traceable through the records of many days from early in May onward through June and July. At this period of the year the daily downward tendency of tree-center temper- ature usually began coincidentally with the rise in the air tem- perature. However, when the air temperature dropped for a few hours below that of the tree center, as, for example, from 1:00 to 7:00 a. m. on June 22, there was at times a slow drop in the tree temperatures. This downward movement, due to air cooling, frequently merged into the cooling associated with the rise in the air temperature, but the latter caused an accelera- tion in the rate of cooling. Thus, on June 22 the rate of cooling just prior to the intersection of the air line with the center line was 0.5? in 2 hours, while immediately following this intersec- tion it was 0.5? in less than an hour. During the latter part of June the period of steady low temperature in the tree center [Vor. 26 204 ANNALS OF THE MISSOURI BOTANICAL GARDEN became longer, indieating an inereasing amount of cooling ae- tion with the advance of the season. On June 1, 3, and 4, 1934, a sharp drop and subsequent rise in air temperature occurred each afternoon, and at the same time a small bend upward and downward in the tree-temper- ature lines appeared. These inverse responses to air temper- ature changes are identical in type with those which occurred during the high-temperature period of the latter part of July, and indicate clearly the concurrent nature of the air-tempera- ture changes and the inverse tree-temperature changes. For several hours on June 26 and 27 the air temperature was maintained at 36 and 37? C., which was as high as on some of the days during the later period of July. Yet the cooling of the center of the tree was much less marked, which shows that high temperature alone was not sufficient to occasion the excessive thermostatic action of July, 1934. At air temperatures which averaged below 35° C., as in a long period prior to June 26, the two tree temperatures were very close, usually not more than 2° apart, thus giving evidence of thermostatic cooling of the cambium. On several days during May (6-9, 18-22, 30 and 31), 1934, the tree-temperature line showed definitely a greater rate of increase at about the point on the air-temperature line where the afternoon decrease began. For some of these days also it is impossible to calculate a ratio between the T4 rise and Тн rise, since no evident increase in tree temperature took place until this afternoon inflection of the two lines showed on the record. This lack of rise in the tree temperature in the early part of the day, at the time that the air temperature was in- creasing, can only be explained by a cooling action within the tree associated with increasing air temperature, and the rise at the time of the air-temperature decrease must be due to a decreasing cooling action associated with decreasing air tem- peratures. This may be demonstrated also in the following manner. The period of temperature rise in the tree center may be divided into two portions, the first, up to the time of the be- ginning of the afternoon decline in the air temperature, and the second after that time. During the first portion the increasing 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 205 air temperature, if there were no concurrent cooling action, should have eaused a more rapid rise in the tree temperature than during the second, when the air temperature was actually falling. If the rate of rise in the tree temperature was greater in the second than in the first portion it would indieate an ex- cess of cooling action during the first portion of the curve. Тһе following data for several of the days in Мау, 1934, thus clearly indicate thermostatie cooling at this period. May 3--Тн minimum, 19.25? C. at 9:30 a. m. Тн at 4:30 p. m., 21.25? C. or 2.0? rise in 7 hours. Тн at 9:00 p. m., 22.00? C. or 0.75? rise in 4.5 hours. Rate during 1st portion of rise, .28? C. per hour. Rate during 2nd portion of rise, .16? C. per hour. Here it is evident there was no excess cooling action, since the rate in the latter portion of the curve was much less than during the first portion. The values for other days in May, cal- culated in similar fashion, are listed below: May 4—Rate 1st portion of eurve, 0.05? per hour. Rate 2nd portion of curve, 0.25? per hour. May 6—Rate 1st portion of curve, 0.11? per hour. Rate 2nd portion of curve, 0.25? per hour. May 8—Rate 1st portion of curve, no rise discernible. Rate 2nd portion of curve, 0.17? per hour. May 9—Rate 1st portion of curve, 0.11? per hour. Rate 2nd portion of curve, 0.25? per hour. May 29—Rate 1st portion of curve, 0.33? per hour. Rate 2nd portion of curve, 0.41? per hour. Considerable rates of inerease are therefore evident on May 4, 6, 8, 9, and 29, during the second portions of the curves, thus indicating cooling action during the first portion. The record for May 31, 1934, may be studied as a typical ex- ample during the portion of the year when medium tempera- tures dominated and the thermostatic cooling definitely af- fected the tree temperatures (table хі derived from the graph- record). The beginning of the rise in air temperature and the [Vor. 26 206 ANNALS OF THE MISSOURI BOTANICAL GARDEN beginning of the daily increase in the rate of decline in the tree temperatures were coincident, at about 5:30 a. m. From about 8:30 a. m. to 5:00 p. m. the tree center remained steadily at 22.75? C., and the cambium slowly rose from 24.50 to 24.75? C. At 5:00 p. m. the air temperature began its usual decline and simultaneously the tree temperatures began to rise, for one hour very slowly and then more rapidly. TABLE XI DATA FOR RECORD OF MAY 31, 1934 Temp. Rate per Item Time "Є hour l. 1st T, min. 5:30 a. m. 22.00 2. 1st intersection of T, and Ty 6:30 a. m. 24.00 3. Ta min. (beginning) 12:15 p. m. 22.75 4. T, max. (beginni 12:15 p. m. 35.00 5. Tim n 5:00 p. m. 35.50 6. Beginning 2nd phase of p. m. rise in Тн 6:30 p. m. 23.00 7. 2nd intersection T, and Ty 1:30 a.m. 6/1 25.50 8. Тс min. 8 a. m.-5 p. m. | 24.25-24.75 9. 2nd jns eae Tc and T, 11:15 p. m. 26.7 10. 2nd T; m 12:00 p. m. 26.75 LL рани | Ist phase p. m. rise in Ty} 5:00 p. m. 22.75 12. Beginning 18% phase p. m. rise іп Тс 5:00 p. m. 24.75 13. Beginning 2nd phase р. m. rise in Тој 6:00 p. m. 25.00 14. EI be 2nd phase p. m. decline in 6:30 p. m. 32.50 15. a. n T, 4 minus 2 5.75 hrs. 11.00 1.91 16. Pee Реј EN max, 4 to 5 4.75 hrs. 17. a. m. decline in Ty 2 minus 3 5.75 hrs. 1.25 0.21 18. p. m. decline in T, 5 an 11 8.50 hrs. 10.00 LIT 19. Total rise іп Tj 7 minus 3 13.25 hrs 2.75 0.20 20. Ist phase p. m. rise in Ts 11 minus Я 1.5 hrs 0.25 0.166 21. 2nd phase p. m. rise in Ty 7 minus 7.0 hrs 2.50 0.357 22. lst period p. m. decline in T, 5 minus 14 1.5 hrs 3.00 2.000 23. 2nd period p. m. decline in T, 14 inus 7.0 hrs 7.00 1.000 24. Ist phase p. m. rise in Tg 13 minus 12 1.0 hrs. 0.25 0.250 25. 2nd phase p. m. rise in То 9 minus 13 5.25 hrs. 1.75 0.333 An inspection of the graph-record shows a small but definite bending downward of the tree-temperature lines at 5:30 a. m. coincidental with the beginning of the rise in the air tempera- ture. This demonstrates an increase іп thermostatic cooling when the air temperature was relatively low (i.e. 22.00? С.) 1939] REYNOLDS— TREE TEMPERATURE AND THERMOSTASY 207 and below the tree temperatures, and shows that the cooling aetion was not necessarily associated with high temperatures. From the data in table хі it is evident that the rise in tempera- ture of the tree, associated with the decline in the air tempera- ture, occurred in two stages. During the first, while the air tem- perature was dropping at the rate of 2.0? an hour, the center and cambium rose at the rates of 0.166? and 0.25? an hour re- spectively. During the second phase, when the air-temperature rate of decline was 1.0? an hour, the center and cambium tem- perature rose 0.357? and 0.333? an hour respectively. Since it cannot be assumed that the rate of heat conduction increased, the data cited above demonstrate that the thermostatic cooling was more effective at higher air temperatures. On June 17, 1934, from 6:00 a. m. to 3:30 p. m., there was a slow downward movement of the tree-center temperature from 26.00 to 25.00? C., almost coincidental with an increase in air temperature from 24.50? C. at 5:30 a. m. to 31.75? C. at 10:30 a. m., followed by sharp depressions and rises until about 6:15 p. m. At this time a sharp drop from 30.25 to 21.00? C. resulted in an immediate small swerve upward in the center temperature of about 0.5? and in the cambium of about 0.75? C. At about 3:00 p. m. both tree temperatures showed a small but distinet swerve downward in response to an increase in the air temperature from 25.00 to 31.25? C. About 0.5 hour after the intersection of Ta with To and 1.0 hour after the inter- section of Ta with Ти in the afternoon the Tc and Тн lines be- сап a slow decline in response to the lower air temperature. This was due to heat conduction outward from the tissues. Тһе record for June 17 emphasizes а number of important points. (1) At this date, well before the hot dry period of late July, the thermostatic action can be seen, not only from the calculations given in table xm but also from the curve where sharp changes in the air temperature occurred. (2) The com- pound character of the tree temperature due in part to heat gradients across the tissues and in part to the thermostatic cooling action is indicated. (3) That the temperature of the cambium, as well as that of the center, is in part due to a local [Vor. 26 208 ANNALS OF THE MISSOURI BOTANICAL GARDEN cooling of the tissues is demonstrated by the almost immediate reduction of the cambium temperature concurrent with the rapid inerease in the air temperature and vice versa. (4) The phenomenon heretofore called ‘‘lag’’ is not simply due to slow conduetion of heat into or out of and across the tissues as has been explained by other investigators. This сап be demon- strated by a comparison of this record with the records for previous days, as indicated in table хп. On June 14, 15, апа 16, for example, there was for each day an interval of from 10 to 12 hours between the middle of the maximum-temperature period of the air and the middle of the maximum-temperature period of the tree center. This formerly has been designated as а “Час”” of 10 to 12 hours and ascribed to slow conduction of heat. On June 17, between 5:00 and 7:30 p. m., the sharp drop in air temperature, with mid-point at about 6:30, had its maximum effect upon the cambium and the center of the tree at 7:00 and 8:00 p. m. respectively, or 0.5 hour and 1.5 hours afterwards. Then the cooling action due to the lower air tem- perature began to reduce the tree temperatures. These inter- vals of 0.5 and 1.5 hours constitute a partial measure of the true ‘‘lag’’ in the usually accepted sense of that word. A heat gradient from the inner to the outer tissues sufficient to cause the beginning of a detectable decline in the center temperature was attained in about 1.5 hours. However, if an internal ther- mostatie cooling was taking place, then a decrease in the rate of this cooling due to decline in the air temperature would tend to neutralize for a while the loss of heat to the outside and thus extend the time before the beginning of the decline in the tree temperature. Hence the 0.5 hour and 1.5 hours represent more than the maximum which, under these circumstances, we should assign as the true ‘‘lag’’ period due to slow heat conduction. It is evident, in any case, that since there was little or no rise in Tu while Тл was at its maximum, the 10-12-hour difference be- tween the maximum of the air and that of the tree center on June 14, 15, and 16 could not be due primarily to a slow conduc- tion of heat inward across the tissues, but to a reduction in the cooling action. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 209 TABLE XII "LAG" BETWEEN ТА МАХ. AND Тн MAX., JUNE, 1934 (1934) Diff. T, max. T, max. Diff. June T,max.* | Тн шах.* | degrees timeday | time night time 11 29.501 23.751 5.75 1 :30 10.5 hrs. 12 27.251 22.501 4.75 4:00-5:30 |10:30—1:00| 5 hrs. 13 29.751 23.00 6.75 1:00-5:00 11-2 9 hrs. 14 28.75t 24.001 4.75 1:30-6:00 | 12:30-2:30 | 10 hrs 15 31.751 25.001 6.75 1:00-4:00 | 1:30-3:30| 12 hrs. 16 33.251 26.251 7.00 1:30-5:00 | 1:30-5:00 | 12 hrs. * ТА max. and Тн max. taken as: 7 central line through а — н period of less than 0.50? variation, ог t the maximum held for more than 1 ho From the cases cited it is evident that at least during the period from early May, 1934, onward there was a thermostatie eooling which often was sufficient to more than overcome the effect of the heat from without. Тһе cases cited will show that this phenomenon was associated not only with the year 1934, when there were exceptional conditions of heat and dryness, but also with other years under moderate temperature condi- tions. In 1932 the thermostatie action is traceable back through July and June (at least to June 4) by the actual drop in the center temperature with the morning rise in the air temper- ature, and by the very slow concurrent rise in the cambium tem- perature. The latter also showed even on June 4 an accelerated upward movement when the air temperature began to drop. During periods of moderate fluctuation of the air tempera- ture, e.g., between 15? and 25? or 30? C., as during much of the month of May, 1934, the cambium and center temperatures usu- ally kept within 1 to 2 degrees of each other, with the cambium usually a little higher. Тһе rise and decline of the tree tem- peratures usually began within less than 2 hours after the intersections of the air-temperature line with the tree-tem- perature lines, the cambium temperature responding most rapidly. It has already been pointed out that when the tree temperatures were within 2 degrees of each other and the air temperature several degrees above that of the cambium a cer- tain amount of thermostatic cooling was indicated. Usually [Vor. 26 210 ANNALS OF THE MISSOURI BOTANICAL GARDEN this type of record merged a few days later into that in which thermostasy was indicated by a long ‘‘lag’’ period between the morning intersection of T4 with Тн and the beginning in the rise of the tree-center temperature. The various stages in in- creasing thermostasy during the early part of the season can be seen by comparing successively the records of April 20, 24, 30, May 3, 4, and 5, 1932. On April 20 there was no evidence of eooling aetion, since (1) the Тн line began its rise 1.5 hours after the morning intersection of T4 with Тн; (2) the Tc line followed elosely the rise in T4 and at least 4.0? above the Тн line; and (3) there was no inverse reaction of the Tc and Тн lines at the beginning of the Т, decline in the afternoon. On April 24 (1) the somewhat longer interval, about 2.25 hours, be- tween the intersection of Тл with Тн and the beginning of the rise in Тн, and (2) the somewhat closer approach of the Tc to the Тн line, suggest a slight thermostatic action. A somewhat more pronounced, similar eondition on April 30 and May 3 is further indication of increasing cooling action. On May 4 (1) the 3-hour morning postponement in the rise of Тн, (2) the slow rise of Ти and То, with a several-hour (ca. 6 hours) flattening of the To curve, during the rise in Ta, (3) the close paralleling of Tc with Ты, (4) the distinct rise in Те concurrent with the de- cline in Та, and (5) the inflexing of the Ти line as well, during the decline in ТА, all give clear evidence of thermostatic cool- ing at this time. АП of these features are further strengthened in the record of May 5. In this series of records thermostasy oceurred at moderate air temperatures, with maxima around 30.0? C. for only short periods of the day. An inspection of the graph-records, how- ever, will show that in general there was, through this period, an increasing amount of heat each day, as indicated by the greater area in the chart covered by the Т^ line in the later days. The normal direct reaction of the tree temperatures to changes in the air temperature, as shown in the cases cited be- low, contrasts in certain definite ways with the indirect ther- mostatie reaction just illustrated. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 211 The records for March 18 and 19, 1932, are typical of the re- lationship of the three temperature lines at a time when the tree temperatures were not complicated by transpiration in the tree or by the zero-line adjustments. The cambium tempera- ture was about 4 degrees higher than that of the tree center and was nearly halfway between that of the air and of the tree center. This may be used as one criterion for judging when cooling action became somewhat effective in retarding the di- reet influence of the atmospherie temperature upon the tree temperatures. The fluctuations of 12.0 to 15.0? between the night and day air temperatures resulted in almost parallel advances and de- clines in the tree temperatures, with the latter below the air temperatures from about 8 a. m. to about 6 to 7 p. m., and above them during the night. Тһе beginning of rise in the center tem- perature on March 19 was about 1.5 hours after the morning intersection of Тл with Тн. The center temperature attained its maximum 1.5 hours after the afternoon intersection of Ta with Tz. On March 17, 1934, before foliage had developed, there was a sharp drop in the Ta line from 21.5 to 11.5? C. in about 0.75 hour. Тһе Тн line continued its upward movement 0.5? above the intersection of T4 with Тн for about 0.5 hour, and the Tc line continued less than 0.25? above the intersection of T4 with Те for about 0.5 hour. Both Тн and То, after retaining their maxima for about 1.0 and 0.5 hour respectively, began a steady fall for about 20 hours, gradually approaching the Т, line. This demonstrates the typical reaction of the tree tempera- tures to a very rapid change in air temperature when not com- plicated by the presence of transpiring foliage or other dis- turbing faetors such as occur when the tree temperatures eross the zero line. The true heat diffusion ‘‘lag’’ was about 0.5 hour for the cambium and 1 hour for the tree center. The maximum Та, which held for about 2 hours just before the sudden drop, was 22.0? C. The number of **degree-hours"' of atmospheric change was about 37, producing about a 10 degree-hour change in the tree center or a ratio of about 3.7 1. This appears to be [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN 212 #'0 „0т ^o[oq пода prog S'e эш ‘d 00:% ii 6 w ‘d g —/ ше 06:01) ee 006 044 8 —0$:5 [ш ‘е 06:8 | 6072 00'€T 6/79 ЄТ пода роо 047), зш ‘d 0є:/ "ш ‘а og:T су “от -00:9 [ш ‘е Gp: GL 026 | OOST 9 -06:017ш “ЕС%:) | 6/8 02786 22'61 +0Т 0201 "ш се 06:21 ш "а 0е:$ не сот |-u 'd бе:тү[ ш ‘е 02:01 OL | OCII | OCT 8 -00:6 [ш 7% ср:9 07Т | 00°6T 0072 6 пода plop 8 44 "17% 00:6 "ш 'd 00:9 SUR IT —00:3r/m `4 00:71 44 0577 0076 “8 -00:6 [ш 7% 00:6 | CL'OI | 00°$Т Go's L SL'0T “Qo [948 prop 079 ‘a 'd 00:6 "ш “а 02:2 cg от —0£:4 [ш ‘в 06:6 0'9 0СТТ | OS'S 4%) —0€£:6 ш ‘е 00:2 | 066 00°9T 0479 86 е-е "u ‘d 08:8 pow 35°0Т | ur'd 08:8 [w'e сто S'e 06% 0070 2 —05:5 Ue 08:4 | 006 006 0070 16 ов Hy, | SMO moy лпоц вәәлдәр влпоц moq moy зээ18эр "Uu | ша ‘хеш Н, "шш "L ша [xeu EL uu EL| ga | ‘хе УТ, эшш YL чпа хеш [| „ши | (ze61) ƏSH VL ASVISONWHWNH,L ЧО ӘМІЗННЯ Ag амачавзта LON NAHM ичптучнаиняу чачу NO ячптучяаинх UIV NI ЯЅІЧ AO HONAATANI IIIX W'IH VL 1939] 213 REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 'алпувлодшој 991} ut ISPA €? osn9o JOU p[noo олпувлодшеј ле UI ƏSH 993 зитоа вид MOTE 'әвїл Аер в} UF IUH әлпуеләйшәҙ-әәлҙ IYJ рәѕѕолә JUF олпувлодшој-лув IYJ YOY 38 3ujod 993 SLM у „ст "О „01 AO[9q Пэм SEM UoruA ‘хеш ут, злоце Алод $ '9'g/*9'$ = HL/VL JO ONLI в ‘9913 әцу UF OSTA ,0'g е рәвпво {у 2078 03 0 шолу әлпјеләйшәј} ITV Ul OSTA е 8T "4ӘЯ чо # 'do1p 531 u'e3eq әц уд, 941 1933? 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"ui 'd Og: IT "ui *d 06:6 TET от —05:6 [ш ‘е 06:10 0079 0697 | OS OT L -06:% ш 7% 06:6 | OS'IT | 00706 0€'0I 86 007% "ш “а 02:6 эш 'd 00:6 eje “8 —00:'8 үш 7% Q£: TT, 00% сет | 9651 Ӯ -0ӯ:6 (шо CP: OT) 92'9 90781 0%2Т 26 04% "ut "d 00:01 "ui ‘d ey: 006 “6 -06:8 [ш ‘е 00:11) 09% | 9291 | SEST | 99 -gy:p [ш ‘e 06:ТТ| 006 60710 cost 96 9276 "ui ‘d 00:9 сүзі вт | ‘wd pr-or[|ur "e 06:01) 5026 | 0991 | 952 GL —08:$ fu L 00:8 | SZ'TT | 667006 06 35 4/76 "ui 'd 00:3 0091 ті | ‘wd ТІ-6 fw e 06:01) 3/6 ІТ | OST L -06:2 |ш ‘е 06:8 | OQ'OT | 0677 | LOST v6 00% "ui “4 00:61 эи 'd ogi $008. L -00:6 [ur'd 00:5 | 00% | 00% 00'T oP —0£:g [ш "е GT: TT] 0075 00°9 00°T 55 82% ‘ur “4 00:01 "ui 'd 00:8 Mu 6 -06:2 [me 06:01) 927 | 00°9 €e'T 49 -00:6 [ur^9 06:6 | 0072 €o'8 “СТ 66 (Vor. 26 214 ANNALS OF THE MISSOURI BOTANICAL GARDEN the usual approximate, maximum ratio when the disturbing factors noted above are absent. Various other early-season records showing thermostasy have been previously cited, so that there is ample evidence of the presence of this phenomenon at various seasons and in dif- ferent years. Direct insolation of the tree accounted for a rise in the cam- bium during certain parts of the season. For example, on March 14, 1934, at about 9 a. m. the cambium temperature be- gan to rise from 6 to 8° C., while the center temperature re- mained steadily at 5.5° C. and the air temperature remained below that of the cambium. A similar situation existed on the morning of March 18, when the cambium rose from 1.0 to 2.25° C., while the air temperature was from 1 to 2° below zero. On April 12, 15, 19, 20, 21, 24, and 25, direct insolation caused a rise of about 3.0? in the cambium temperature under circum- stances similar to those of March 14 and 18, and with no evident corresponding rise in the center temperature. Several other examples are to be found in the records, as on February 26 and 21, 1932, and on January 31 and February 1, 1931, when the cambium remained approximately 2.5? higher than the atmos- phere for from 3 to 4 hours. The direct effect of air temperature upon the tree tempera- ture is well shown in table xm under the column ТА гіѕе/Тн rise. It is evident from these data that since the ratio never reached 3:1, less than 3° of air-temperature rise was needed to cause a rise of 1? in the tree center. This period of the year was of course free from the complication of thermostatic cooling or other effects due to the presence of foliage and its transpira- tion. It will be noted that this rule held at all temperatures above 0° C. and when the minimum air temperature was at or above that of the tree. When the air temperature was below that of the tree it of course could not raise the tree temperature, and in preparing the table all air temperatures below the mini- mum tree temperatures were ignored. Any heat derived from direct insolation of the tree trunk at the thermometer level would tend to increase the factor “Тн rise’’ and thus lower the 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 215 ratio. That this possible disturbing factor probably did not seriously alter the ratio is indicated by a comparison of the ratios in table хш with those between the temperature drop of the air and of the tree at night during this same period, as seen in table xiv. The average ratio during the day was about 1.71:1 and during the night about 1.64 :1. Discussion AND CONCLUSIONS LAG In former publications the word ‘‘lag’’ has been used to cover any departure in time between an air temperature and a supposed correlative tree temperature. Most frequently it has been used to cover the period between an air-temperature maximum or minimum and the following tree-temperature maximum or minimum respectively, on the assumptions, first, that the transfer of heat into or out of a tree requires time, and second, that the tree-temperature maximum or minimum is di- reetly and only due to the preceding air-temperature maximum or minimum more or less modified by factors of relatively slight importance. The first of these assumptions is of course correct, but many authors have also tacitly assumed that the time con- sumed in the transfer of heat would vary from time to time in the same tree as well as in different trees. Тһе second assump- tion, as has been demonstrated in this investigation, will have to be fundamentally and seriously modified, although it is clear that the air-temperature changes under certain conditions are reflected directly, in modified form, in the changes in the tree temperatures. An examination of the records as already presented demon- strates that the rate of conduction of heat across the tissues is for an individual at a given place a constant, which under the given conditions may be stated as follows: A readily detectable change of temperature at the cambium layer occurred in less than 0.25 hour and in the tree center in less than 1.5 hours. For purposes of this paper these periods of time have been called the ‘‘true lag’’ periods. Theoretically a change of temperature [Vor. 26 216 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE XIV INFLUENCE T REDUCTION OF AIR Уе TREE TEMPERATUR (1932) Ratio Feb. | Т, шах. | Т, min. | T, 1088" | Ти max. | Tg min. | Tyloss | 221988 Тн loss 7.5 7-8 7.50 0.00 7.5 7.5 4,5 3.00 E 15.75 12-13 | 17.75 2.00 15.75 | 17.75 5.5 12.25 deep 12.25 1.15 13-14 | 13.00 5.95 7.75 9.00 1.0 8.00 T aie 8.00 i 8.00 19-20 5.00 | -3.00 8.00 5.00 | -1.00 6.00 383 6.00 6.50 29-93 5.00 | -15 6.5 5.00 1.00 4.00 Mesa 4.00 7.00 24-25 | 11.00 4.00 7.0 11.00 7.25 3.75 ы, 3.75 7.50 25-96 | 16.00 8.5 7.50 16.00 | 12.25 3.75 ее 3.75 1.25 26-97 | 16.95 9.00 7.25 | 16.75 | 12.25 4.50 ins 4.50 9.50 27-98 | 15.50 6.00 9.50 | 15.50 10.50 5.00 С 5.00 28-99 | 16.50 7.00 9.50 | 16.50 12.00 4.50 „9.50 4.50 99-3/1| 15.25 9.00 6.25 | 15.95 10.50 4.75 6,25 4.15 padok of tha air-tenaperature line with the tres temperature Rie (ihe Tz DAA.) aed the point of actual minimum air temperature (Ta min.). at the surface of the tree would be propagated through the tis- sue at a very high rate, of the order of the propagation of any other true wave in elastic matter, and in general determined by the thermal conductivity of the tissue. Since the detection of the change would depend upon the relative delicacy of the ther- mometer and since the limit of the instrument used here was about 0.25° C., in order to record a temperature rise, enough heat must have accumulated at the point of its insertion to cause .25° of temperature change. The average density and specific heat of the system would be the main factors determin- 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 217 ing the time consumed before enough heat had accumulated to cause this change. The rate of this accumulation of heat in the tissue is dependent upon the amount and rate of change in the air temperature and the diffusivity of the system, designated by the symbol ‘‘h?’’ which equals K/CP, where ‘К? is the con- stant of thermal conductivity, “С” is the specific heat, and “P” the density (Ingersoll & Zobel, 713). The ‘‘true lag," as used in this paper, is therefore essentially invariable, at least within the medium temperature limits and the usual liquid water content of the tissues. In many of the older papers on this subject, however, the ‘‘lag’’ periods reported were ex- tremely variable and irregular from day to day and over longer stretches of time. This was due partly to the method of de- termining the “Чао,” and partly to the unrecognized thermo- static factors. It has already been noted that the intersection points of the air-temperature line with the tree-temperature lines are most important in the temperature curves, since they indicate us- ually momentary identical temperatures. These intersection points, which are here called iso-thermal nodes, have seldom been noted heretofore in the numerical data of this subject, and their significance has therefore been overlooked. It will be evi- dent from an examination of the various temperature graphs during medium temperatures that the period from the air- temperature maximum to the following iso-thermal node was very irregular. This was influenced, first, by the rate of rise of the air temperature to the maximum, which therefore af- fected the rate of rise in the tree temperatures. Second, the length of the maximum period also influenced the rate and length of the rise in the tree temperatures, as well as helping to determine directly the length of time from the air maximum to the intersection. Since in most former records the length of this maximum period was undetermined, its effect on ‘аз’ was entirely ignored. Third, the rate of decline in the air tem- perature prior to the intersection greatly influenced the ap- parent ‘‘lag’’ period. In general, a slow decline postponed the time of intersection of the lines, sometimes by many hours, and [Vor. 26 218 ANNALS OF THE MISSOURI BOTANICAL GARDEN a rapid decline greatly shortened this time. Now, since the maximum tree temperatures must occur at or after the inter- sections it is evident that the ‘‘apparent lag’’ between air and tree maxima must be an extremely variable quantity. Fourth, the rate of decline in the air temperature subsequent to the in- tersection caused variations in the length of time between the intersection and the maximum in the tree temperatures. This was influenced largely by the diffusivity of the tissues, since loss of heat by the tree could now take place in proportion to the speed of decline in the air temperature. Analogous considerations demonstrate that the **apparent lag’’ between the air and tree minima also is necessarily very irregular. It has been unexplained in former investigations, due largely to incomplete data and a lack of recognition of the iso-thermal nodes. The two other factors, however, which in even greater measure and in a more important manner influ- ence the lengths of **apparent lag," are: first, the adjustment period at the zero line, and, second, the thermostatic cooling of the tissues. In most of the periods of declining air temperature in which the tree temperatures fell below 0? C., the tree-temperature minima were delayed by the long zero-adjustment period until many hours after the beginning of the air minima. In a few cases, notably that of January 28, 1934, a rapid decline in air temperature carried the tree temperatures below the zero line, and the tree minima were delayed due to adjustments gradually made while the tree temperatures were dropping. In a similar fashion, the tree temperature maxima, following a rise in air temperature which carried the tree temperatures above zero, were usually attained many hours after the air maximum, and in many instances the air temperature had several maxima and minima which were not even registered in the tree tempera- tures. This delay and frequent lack of registering of maxima were associated with the long zero-adjustment period which greatly modified the usual somewhat rhythmic rise and fall in the tree temperatures associated with the usual daily rhythm of air temperatures. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 219 The effect of the thermostatic cooling upon lag was shown in the extreme form in July, 1934, when the low tree temper- atures and the high air temperatures usually exactly coincided (and vice versa). The apparent rhythmie lag of approximately 12 hours was then entirely false, since the tree minima and maxima had no relationship to the preceding air minima and maxima respectively, as demonstrated in a former section of this paper. In less extreme cases, as during the latter part of July, 1930, the minimum period in the tree center partly co- ineided with the air-temperature maximum and vice versa. This condition in part obliterated the **apparent lag’’ period by substituting more or less of the false ‘‘apparent lag’’; in other words, the tree minima, due to preceding air minima, merged more or less completely with the minima due to the thermostatic cooling action. Likewise, the preceding air тах- ima caused a rise in the tree temperature which merged with the rise associated with the decreasing thermostatic cooling action, and the apparent lag period was somewhat extended.’ FACTORS AFFECTING TREE TEMPERATURES As was early recognized by plant physiologists, the atmos- phere and direct insolation are the main sources of heat for the plant. Many attempts were made in the early days of the sub- ject to demonstrate elevated temperatures of the embryonic regions of the stem associated with respirational activity, but few satisfactory results were obtained because of the masking effect of the rapid and excessive changes due to the outside en- vironment. In the course of these investigations experimenters became greatly impressed with the rhythmic alternations of temperatures in the tree, apparently following more or less regularly those of the air. Many of the investigators recorded considerable deviations of the tree temperatures from those of the air, but were usually content to point out that the mean temperatures of the tree and of the air ran parallel. From the present records the importance of the air temperature as the main factor in determining directly and also indirectly the tree 1 Another type of ‘‘ false apparent lag" has been described in a preceding section. [Vor. 26 220 ANNALS OF THE MISSOURI BOTANICAL GARDEN temperature is evident. However, the faetors influencing the diffusion of heat through the tissues, which is a basie physieal phenomenon, must be clearly defined in order to interpret the various reactions indicated in the graph-records. The order of magnitude of the thermal conductivity of wood is indicated by that of pine, which at 15? C. and perpendicular to the face is given as 0.361 A x 10, while that of water at 12? C. is 1.36 Ax 10?.! Hence the heat conductivity of the tree trunk would tend to increase or decrease (directly) with an increas- ing or decreasing proportion of water. As indicated later, con- current with a decreasing water content there is an increasing amount of water vapor, and since its thermal conductivity is less than that of water (e.g. at 46° C., 4.58 à x 107) the rate of heat transfer in the entire system would be further reduced by this factor. Under the high transpiration conditions of the summer the center temperature tended to respond less readily to changes in air temperature than under more moderate con- ditions. In light of the above, this may be partly accounted for by a net loss of water from the tissues, resulting in a decrease in heat conductivity. That there is a tendency toward a de- ereasing water content of trees as the transpiration rate in- creases has been demonstrated by various investigators (Mac- Dougal, Overton & Smith, 29), and a study of the various pat- terns of water distribution in tree trunks at different seasons points toward the general conclusion that there are sharp dif- ferenees in seasonal distribution and quantities of water in tree trunks (Craib, 718-283). Since the specific heat of ice at -10° C. is approximately half that of water at 0? C. (0.48 vs. 1.0087) the reactions of the tree temperatures to subfreezing air temperatures would tend to be more rapid when the water in the tissue is frozen than when liquid. Moreover, the heat conductivity of ісе is more than quadruple that of water, or about 5.7 А x 103. This physical factor also would tend to increase the speed of reaction of tree temperatures to low air temperatures as compared with the reaction at temperatures above zero. While it is not possible * Physical data from Lange (737). 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 221 at present to determine from the records the relative quantita- tive effects of these factors they must be considered in any attempt at a complete analysis of the factors concerned. In general, it has already been shown that the ratio between the increase or decrease in atmospheric heat and the increase or deerease in the center temperature is higher at higher temper- atures and lower at lower temperatures. This must be aseribed mainly to the thermostatic cooling at higher temperatures. However, these heat-transmission factors under extreme condi- tions may be sufficiently important to affect noticeably the gen- eral result, as would be indicated by the fact that when the tree was at sub-zero temperatures the ratio air-temperature change/tree-temperature change was unusually low, even reaching the theoretical ratio of 1:1 as cited elsewhere. This contrasts somewhat sharply with the usual ratio at tempera- tures above zero when there was little thermostatic cooling, and indicates less heat absorption and more rapid heat trans- mission at sub-zero than at supra-zero temperatures. Dur- ing the winter sub-zero periods the tree-temperature lines were more often superimposed and also more closely followed the air-temperature line in its wanderings than during early spring and late fall supra-zero periods. This general observa- tion may be explained mainly by the recognition of these physi- cal factors. In a consideration of the phenomena which have been here- tofore included in the phrase ‘‘zero-line adjustment,’’ it is clear that at or just below zero, because of the latent heat of fusion of ice, heat is steadily given off as ice formation pro- ceeds. The steady temperature at or near the zero line is thus maintained until ice formation is complete, and a continuance of an air temperature below that of the tree would cause a lowering of the tree temperature. The reverse process would take place during the crossing of the zero line concurrent with the rise of temperature. The following data seem to substanti- ate this concept. During the period, January 29-February 6, 1932, the center temperature line held at about —1.5? C. almost steadily, although the air temperature line was above zero for [Vor. 26 222 ANNALS OF THE MISSOURI BOTANICAL GARDEN 3 days or more. However, the number of degree-hours below zero during the first cold spell was about 327, while during this first warm spell, which did not carry the temperature of the tree center above zero, it was only about 244. That this use of degree-hour units is a valid criterion is evidenced by the faet that for the entire period the total degree-hours below zero (421) just about equaled the number above zero (432), the pe- riod beginning at the time that the center temperature line erossed the zero line on its way down and ending when it re- crossed the zero line. The relatively long period during which the temperature of the tree hangs at about 0? C., even when the outside tempera- ture is steadily dropping, may possibly be associated with the phenomenon of change of ''free water" to ‘‘bound water."' Newton and Gortner (7/22) show that winter hardy wheat changes its free- and bound-water relationship at low tempera- tures, and such changes may well occur during this transition period in the tree. Gortner ('37) states that **by bound water we mean water molecules which have been so reduced in activ- ity that they are not oriented into the crystal lattice pattern, characteristic of ice, when exposed to low temperature," and he evidently considers the binding of water as an adsorption process (Gortner, ’38) which, as is well known, evolves large quantities of heat. It may then be possible that more or less of the heat evidently evolved in this ‘‘adjustment’’ period is de- rived from this source. Moreover, it has already been shown that even when the air temperature declines so rapidly that the tree temperatures are carried past the zero point an evolu- tion of heat can still be demonstrated, proving that the adjust- ment process still takes place. Whether or not super-cooling occurs under these circumstances cannot yet be definitely proven, but it is entirely possible. Since this phenomenon is facilitated by the absence of active liquid movement (Luyet & Надарр, 738) and the whole mass of water in a tree trunk is divided by the cell walls and membranes into numerous par- tially immobilized small units, the conditions for super-cool- ing would be especially favorable. The influence of the higher 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 293 osmotic concentration of the biological fluids on the freezing point during the zero-adjustment period is shown by the fact that the temperature during this time was from -0.50 to —1.50? C. instead of 0° C., with the lower temperature pre- dominating when the temperature was on the decline. SOIL TEMPERATURE Several investigators have maintained the hypothesis that the temperature of the ascending soil water eaused tree tem- peratures above or below those of the air. It was pointed out that if the transpiration stream had a different temperature from that of the air it would tend to modify the effect of the air temperature by constantly giving off or taking up heat. In some cases soil temperatures were correlated with tree temper- ature in substantiation of the hypothesis. Hartig (773), in his table п, shows that a cut, living log containing water accumu- lated heat in the direct sunlight, while a standing transpiring tree (oak) under similar conditions, even at 4 em. deep, defi- nitely cooled not only to a temperature below that of the cut log but also in general below the air temperature. The cooling action could be seen in a shaded location also, although it was not so great. The cumulative heating of the log in the sun was marked, especially at the 4 cm. depth. Selected data are given in table xv. TABLE XV DATA ASSEMBLED FROM TH. HARTIG Outside sun Time i Log temp. rise Tree temp. rise or loss or loss or loss 6—8 a. m. 48,2 +3.8° C. -0.3% С 0 a. m. 4112.3? С 46.2? C. +1.7° C 10-12 a. m. 40.4? С 46.5? C. 41.83? С. 12-2 p. m. 41.6? С 42.3? C. 41.2? C m. 11.0? C 42.0? C. 411.5? C 4-6 p.m —2.6° С —2.3° С. 41.0? C 6—8 p. m. –5.8 C —4.0? С. 41.0? C The air temperature (in shade) also showed a decline from 4 to 6 and 6 to 8 p. m. (Vor. 26 224 ANNALS OF THE MISSOURI BOTANICAL GARDEN Several items of interest appear in this table: (1) The mani- fest cooling action in the transpiring tree which held the tem- perature rise to less than 8? C. as contrasted with rise in the log temperature of nearly 21? C; (2) the slower rise in the log temperature as compared with that of the outside, probably be- cause of the high specific heat of water; (3) the continued rise of temperature in the tree due to the fact that the outside tem- perature, although declining, was still above that of the tree and contributing heat to it; (4) the rise in temperature and ac- eumulation of heat in the water-containing, but essentially non- transpiring log. This independent demonstration of cooling aetion, ascribed by Hartig to cool soil water, is of special inter- est, since the data were gathered from a study of a different species growing under different climatic conditions. If in the present study the cooler temperature in the tree had been due to cool water ascending from the lower cool regions of the soil, there should be specific evidence in the records. Cool water, at its maximum speed of flow, passing through the stem for one or more hours, should have somewhat reduced the tree temper- ature during the extended periods of maximum air tempera- ture. However, at no time is there evidence that this took place. Moreover, there is no evidence that during the night a cooling of the tree tissues occurred due to cool water from the ground, since usually when the air temperature was at its minimum, the maximum center temperature had been reached and main- tained. The only possible evidence in favor of the cooling ac- tion of soil water is that early in the morning, before the sharp rise in air temperature, the center temperature sometimes made a slight drop before the sharper drop of the day. How- ever, this can be explained by the same factors that account for the major cooling action as discussed later. Furthermore, the cooling effects reported here could not be considered as due to the temperature of the soil water for the following four reasons: First, the greatest cooling was in the center where, it is universally agreed, there is the least conduc- tion of water and where gases predominate. Second, when the temperature of the air began to drop that of the center be- 1939] REYNOLDS— TREE TEMPERATURE AND THERMOSTASY 225 gan to rise, while that of the cambium usually accelerated its rise. This change of tree-center temperature could hardly be ascribed to a change of temperature in the soil water, nor to its warming-up due to slower conduction, since the center was af- fected as soon as the conducting region. Third, the amount of change in the cambium temperature was somewhat propor- tional to that of air temperature and less than that of the tree center, whereas it should have been more if due to a change in the temperature of the transpiration stream. Fourth, the be- ginnings of these responses were essentially instantaneous, which could not have been true if they had been dependent upon the rise of the water from the soil through 30 to 40 feet of vas- cular tissue. Finally, the marked cooling action during July, 1934, could not have been associated with the passage of cool soil water through the trunk, as evidenced by a comparison of the records of corresponding dates of other years. When, for example, as shown by the continuous chart record during much of July and early August, 1932, the air temperature varied slightly, the temperatures of the cambium and of the center varied mainly between 25 and 30° C. In July, 1934, during the prolonged hot period the tree minima were often close to 15° C. Manifestly, the soil temperature in the same location could not have been approximately 15° C. in 1934, and 25° C. in the cooler year of 1932. While there is thus no evidence that the temper- ature of the soil water is the main factor in controlling the tem- perature of the tree, it seems probable that it is a contributing factor in modifying the final temperature. The same general statement applies, in some degree, to the belief that the warmer soil temperature of winter might be a source of heat which flows upward through the root system into the tree trunk, thus helping to maintain a temperature in the tree trunk somewhat higher than that of its surroundings. Such a hypothesis has no basis in direct observation. STRETCHING OF WATER COLUMNS AND VAPORIZATION The presence of water vapor in the tissues of the tree has long been taken for granted, and Scheit and von Hohnel, by [Vor. 26 226 ANNALS OF THE MISSOURI BOTANICAL GARDEN various ingenious experiments, demonstrated the probability of water vapor in the tracheae. Nevertheless the corollary of this concept, namely, that by the absorption of heat in the process of vaporization the tissues would necessarily be cooled, has apparently not been given due consideration. There has been much discussion concerning the presence or absence of air bubbles in intact tracheae of the hydrostatic system, but at least a certain amount of water vapor would necessarily be present in such bubbles. Тһе amount of vaporization into these bubbles would inerease with an inereasing negative pressure, resulting in an inereased absorption of heat from the surround- ing tissues. Vaporization into the pneumatie system would likewise cool the tissues. If, as is postulated in the traction- cohesion theory of water transfer, the water columns become stretched and if this liquid acts similarly to other substances under stress, it would be cooled in accord with the well-known physieal principle that substances which expand upon heating absorb heat in the process of stretching. Thus two possible physical processes exist which seem to fulfill the general known or postulated conditions in the tree and which separately or to- gether may account for the cooling action demonstrated in these studies. A careful eonsideration of the detailed records and of the various special conditions involved should give some indieations whether one or the other of these physical processes is to be given preference in the formulation of a theory. The general considerations involving the иен be- tween the several faetors under study here have been given in considerable detail by MaeDougal, Overton and Smith ('29). Certain of their conclusions which have important bearings upon this problem are given here. ** A cohesive meshwork of sap occupying portions of all untylosed annual layers of these trees. “Тһе cohesive columns of water occupying the tracheids and vessels are іп a state of tension set up by evaporation from the exposed walls of cells adjoining intercellular spaces of leaves. ** Dendrographie studies made show that the pull set up by water-loss from such surfaces causes daily variations in size of intact stems and trunks, owing to an inerease and decrease of the tension, 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 221 * * Pressures and suetions on the gaseous system within the trunk are readily trans- mitted vertieally for distanees many times the length of the vessels. Tangential transmission of suetions and pressures is at a very slow rate, and is even slower in a neis direction. «с The relative volumes of the hydrostatic and pneumatic systems within the tree are subject to variation during the course of the season. Specific conducting ele- ments may at one time be partially or wholly filled with gas, and at another time filled with water. t‘ Tensions in the pneumatic system may vary from something less than half ап atmosphere to not more than one or two atmospheres, Tensions of the hydrostatic system may vary from a compression or positive pressure to a suction or pull of опе to two hundred atmospheres. ’’ It would appear then from the studies of MacDougal and his associates that the increased foliar transpiration under in- creasing air temperature might produce two effects as related to this problem. The greatly increased tension of those water columns which remained intact would cause absorption of heat from the surrounding tissues. Moreover, vessels might be added to the pneumatic system by the breaking of their water columns, associated with an increased production of water vapor, and the extraction of heat would effect an increased cool- ing in the tissues. This condition of greatly stressed water columns seems to require that the greater cooling action should be at the place of greatest tension, which would be in the younger wood near the cambium zone. However, in these studies the colder area was always found to be in the tree cen- ter, whenever thermostatic conditions could be demonstrated. There seems to be no combination of circumstances in the tree trunk by which the greater cooling action could take place at an outer layer of tissue and cause a lower temperature in an inner region. Although we cannot ascribe the main cooling of the tree center directly to the stretching of water columns, at the cambium layer this might be an important, or even the major, cause. Since the cambium layer would receive much more heat than the center by conduction from the outside, it is probable that there would be a considerably greater potential cooling force there than is evident by the temperature re- corded. If, on the other hand, we assume with Priestley (732) that there is no such great tension on water columns, then [Vor. 26 228 ANNALS OF THE MISSOURI BOTANICAL GARDEN vaporization of water in the tissues appears to be the only ade- quate physical principle to account for the notable cooling ac- tion with its immediate response to changes in air temperature. As this discussion indicates, the conditions necessarily pos- tulated under either hypothesis would lead to some vaporiza- tion. This process absorbs a large amount of heat (584.9 gram- calories per gram at 20° C. to 574.0 at 40° C.) from the im- mediate environment and cools it proportionately. The inner tissues of the tree, being somewhat insulated from the sur- rounding atmosphere, may attain and for some time may hold in part a temperature considerably different from that of the environment. Any conversion of water to water vapor will thus tend to cool the tissues in proportion to the amount vapor- ized. An advancing air temperature would usually induce a higher rate of foliar transpiration which in turn would cause a greater rate of internal vaporization. With a drop in air tem- perature the rate of transpiration, and with it the rate of in- ternal vaporization, would decrease. This would result in a decrease in the cooling of the tissues and a consequent rise in temperature, due to the flow of atmospheric heat inward and possibly to a positive release of heat in the tissues through the transformation of water vapor to water. Since there is a steady flow of heat into the tree, there must be a steady absorption of this heat, as was demonstrated by the fact that the tree temperature does not rise and may even be- come lower. This would mean, under the vaporization hypothe- sis, that vaporization must be maintained concurrently with this inward flow of heat. Since increasing transpiration leads to water deficit in the tissues, including the stem, increased space is constantly being made available for water vapor, more or less in direct proportion to the rate of transpiration. Vapor- ization would tend to continue until an equilibrium has been attained, but due to the changes in rates of transpiration it would not for long remain poised. It is assumed that the walls of the tracheae in the hydrostatic system are constantly moist and that whenever they are in contact with spaces in the pneu- matic system vaporization proceeds as indicated above. More- 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 229 over, throughout the pneumatic system there would be a ten- . dency for the vapor pressures to become equalized. The move- ment of vapor longitudinally would doubtless be very rapid, as MacDougal and his associates (’29) have demonstrated that pressures are transmitted longitudinally at relatively high rates. Imbibition in the walls and diffusion of vapor through the lumina would account for the lateral equalization. The re- lationships of water and water vapor to each other and to the structural units seem to provide an adequate system in which vaporization would be effective in the tree trunk. However, the question of the relationship between the foliar transpira- tion and vaporization in the vascular region is important. It is generally accepted in the traction-cohesion theory that trans- piration causes a definite pull upon the water in the vascular elements of the leaf which is transmitted downward through the connecting vascular elements to the entire body of water in the hydrostatic system. Apparently the tendency toward rare- faction of the pneumatic system which would be induced by the tension on the hydrostatic system is partly compensated, since MacDougal and associates (’29) did not find negative pres- sures in the pneumatic system corresponding with those pos- sible in the hydrostatic system. It would seem probable, in view of the sharp cooling at the tree center, that at least some, if not all, of this compensation is associated with the added produc- tion of water vapor. This might account also for the almost in- stantaneous inverse response of the center temperature to in- crease in the air temperature. On the other hand, Priestley (732) accepts the concept of the presence of water vapor in some elements essentially throughout the vascular system, with the water columns breaking and vapor replacing the water in additional tracheae as transpiration increases. This replac- ing of water by vapor would cause the cooling of the tissues. Priestley’s concept also definitely implies a partial rarefaction of the contents of the tracheae, which might extend rapidly for long distances throughout the vascular system until a tempo- rary equilibrium had again become established. Hence this concept also might account for the almost instantaneous nature [Vor. 26 230 ANNALS OF THE MISSOURI BOTANICAL GARDEN of the temperature responses. The greater cooling at the tree center may be associated with a reduction in the water content there, thus leaving more space for vaporization from the inner front of the hydrostatie system. The effect of temperature upon the water-vapor holding ca- pacity of air is an important factor in the internal adjustments of the tree. Тһе mass of water vapor in saturated air at 102, 209, and 30? С, is given as 9.398, 17.28, and 30.36 grams per cubic meter respectively, or, an increase of over 83 per cent be- tween 10 and 20? C., and of over 75 per cent between 20 and 30° C. Hence, concurrent with a rise in temperature within the tree, in response to a rise in the environmental temperature, there would be an increase of the water-vapor capacity of the pneumatic system. This in itself would cause an increased vaporization with a corresponding abstracting of heat, thus preventing the full potential direct response of the tree tem- perature to changes in the environmental temperature. It would also provide for a more effective increase in internal vaporization associated with increased foliar transpiration. On the other hand, coincident with a decline in the internal tree temperature, there would be a decreased vapor capacity in the pneumatic tissue resulting in a condensation of water vapor to water with its attendant release of heat to the tissues and there- fore a decrease in the cooling action. This may account largely for the fact that even when the tree was bare of foliage and the air temperature rose sharply, as from 10 to 20° C., the tree center failed to respond as rapidly or to attain as high a tem- perature as the air. This phenomenon is well shown in the rec- ords for February 24 and 25, and March 18 and 19, 1932, as well as in many other similar periods of the year. The data given in this paper demonstrate an almost instan- taneous influence of the air temperature upon the cooling ac- tion in the stem. The anatomical structure of the stem system in general provides an excellent channel through which such a rapid action could take place. The veins of the leaf, through the petioles and twigs, connect downward with the cone of vas- eular tissue of the older stems. In passing from the lower por- 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 231 tion of the stem upward the older layers of wood, one at a time, “топ out,’’ but sheathed by and connected with the younger layers. Since the foliage system as a whole is connected with all of the layers of both the hydrostatic and the pneumatic sys- tems, its influence can reach every portion of the vascular sys- tem which is not blockaded against the fluid contents of the tubular elements. Whether we conceive of the transpirational pull acting upon the liquid contents of the hydrostatic system or upon the gaseous contents of the pneumatic system, we have an adequate channel through which this pull may act very rapidly and affect more or less every portion of the vascular tissue. As required by the data in this paper, an increased transpirational pull, induced by increased air temperature, will be transmitted rapidly through the water of the hydro- static system to places where this system and the pneumatic system come in contact. There the water will tend to retreat into the tracheae, thus tending to increase the air space. Be- cause this reduces the vapor tension in the air space instan- taneous vaporization into the pneumatic system will take place, the amount depending directly upon the strength of the trans- pirational pull. It seems probable then that a considerable amount of the cooling action in the tree is associated with in- ternal vaporization into the pneumatic system. In addition there may be a certain amount of cooling in the hydrostatic system, associated with and in direct proportion to the amount of stretching of the water columns. This physical action might under some circumstances cause the major portion of the heat absorption from the tissues of the hydrostatic system, depend- ing upon the ability of the system to develop a continually in- creasing amount of stress. If the water were immobilized in the tracheae, or the transpirational pull ceased to increase and the system were then at rest, so far as additional force is concerned, there would then be no additional cooling and the temperature would begin to rise due to the inward flow of heat. This latter condition would perhaps be the main reason that the temperature of the cambium tended to rise earlier in the day than did that of the center, when the air temperature ap- proached and held its maximum. (Vor. 26 232 ANNALS OF THE MISSOURI BOTANICAL GARDEN А second question in connection with the thermostatie action is why the cold temperature of the tree is maintained for a time and then, in immediate response to the beginning of the decline in the air temperature, begins to rise. Because of the high spe- cific heat of water and its low thermal conductivity the layer of hydrostatic tissue acts as an excellent insulation, preventing the rapid inflow of heat to the inner tissues. This, together with such positive cooling as may take place in the hydrostatic sys- tem, would tend to hold the low temperature of the interior. When, however, the air temperature begins to drop, the trans- pirational pull decreases, the stressed hydrostatic system tends to reoccupy some of the pneumatic area, and vapor changes back to water, thus releasing heat. It appears then that all of the major questions associated with the thermostatic action are answered on the basis of the hypothesis discussed above. At different times of the year and under different climatic conditions these various modifying factors differ in their in- fluence on the tree temperatures and on the form of the curves, so that it is difficult to draw definite conclusions as to their im- portance except in certain of the more obvious cases. Broadly speaking, the temperature of the environment is the major fac- tor determining the tree temperature. Certainly the major modifying influence around the zero point is the physical and physiological adjustment which takes place, while at sub-zero temperatures the tree temperatures closely follow those of the air. Under conditions of high transpiration, especially when due to high temperatures, the thermostatic cooling is the main modifying factor, and this may at times nearly cancel the effect of increasing air temperatures. During moderate tempera- tures thermostatic action is more or less manifest as a modi- fying factor, especially during the period of completely de- veloped foliage. Throughout all of the year the form of the curve is greatly influenced by the speed of air temperature change and the lengths of the maximum and minimum air-tem- perature periods. It is especially important, in attempting to explain the apparent temperature responses in the tree, to lo- cate the iso-thermal nodes and to determine the conditions be- fore and after these points. 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 233 From time to time during the last hundred years the subject of water vapor in the vascular system of plants has been dis- eussed in botanieal eontributions. Тһе accurate, refined tem- perature-recording apparatus used in this study, combined with other appropriate studies, should develop important in- formation toward an understanding of water-vapor in relation to the hydrostatie system and of its significance in water trans- ort. From the data presented in this paper it seems evident that the severity of temperature extremes and of temperature changes may be considerably mitigated for the plant through the zero-adjustment period and the thermostatic action. Much higher temperatures in the plant tissues certainly would occur were it not for the latter, and it may be significant that whereas temperatures capable of injuring protoplasm might readily de- velop from direct insolation, injury of this type seldom occurs under active transpiring conditions. In this investigation cam- bium temperatures were held well below 40? C., although even the shade temperatures on some of these days continued above 42? C. for several hours. Atthe other temperature extreme, the injurious effects of the freezing and thawing may perhaps be somewhat reduced by the long period over which the uniform temperature close to the freezing point is usually maintained. SUMMARY 1. Former studies of tree temperatures were inadequate be- cause of lack of proper apparatus and of continuous observa- tion. 2. A continuous, accurate, detailed, automatic record of air temperatures and cambium and center temperatures of a cot- tonwood tree was kept for about four years. 3. A typical record for one day is described; special precau- tions which are necessary in interpreting the records are cited; and the ‘‘degree-hour’’ is described. 4. Asummary of certain general results shows that at about the zero point the tree temperatures usually do not follow im- mediately that of the air, and often do not drop below zero until [Vor. 26 234 ANNALS OF THE MISSOURI BOTANICAL GARDEN after 24 or more hours, whereas below zero as a rule they closely approximate the air temperature ; at high temperatures there is a thermostatic cooling action in the tree tissue which partly or entirely counteracts the effect of the flow of heat in- ward; in extreme cases a temperature at about 15° C. was main- tained when the air temperature was about 42° C., and the cam- bium was intermediate; high foliar transpiration producing a water deficit in the vascular tissues is indicated as inducing in- ternal vaporization and consequent cooling of the center; at medium air temperatures the tree temperatures followed them, but considerably modified by thermostatic cooling and other factors. 9. A detailed examination of a number of ‘‘case studies’’ during the low temperature periods demonstrated that the temperature of the center has a distinetly modifying effect on that of the cambium ; that after the zero-adjustment period the ‘Јав? was for the cambium about 0.50 hour and for the center about 1.5 hours; that during the zero-adjustment period the ratio air-temperature change/tree-temperature change was high and in sub-zero weather low, even attaining the theoreti- eal value of 1:1; that even when a rapid drop in the air tem- perature carried the tree temperatures aeross the zero-line with little ‘‘apparent lag" the internal adjustment сап be demonstrated by a study of this ratio. 6. ‘‘Case studies" of high-temperature periods demon- strated that the thermostatie cooling of the tree tissues was a universal phenomenon ; that this was essentially an instantane- ous response to changes in air temperatures; that the cambium was kept at a lowered temperature by this action; that the tree temperature was a resultant of the flow of heat inward and of the thermostatie cooling; that from July 13 to 26, 1934, the ex- ceptional uniform conditions produced approximately a **con- trolled experiment" for the study of the effects of air temper- ature upon those of the tree; a modified ‘‘degree-hour’’ method was useful in estimating these effects; that ‘гое lag," which is the measure of the rate of flow of heat across tissues, can be distinguished from ‘‘apparent lag," which is a composite of 1939] | REYNOLDS— TREE TEMPERATURE AND THERMOSTASY 955 many factors; that **apparent lag’’ was essentially eliminated by the thermostatic action during this exceptional high temper- ature period; that direct insolation was a minor factor at this season of the year; that the ‘гие 18677 in the cambium was 0.50 hour and in the center 1.50 hours or less. 7. Тһе main conclusions from the selected ‘‘case studies’’ during the medium temperature periods were that thermo- static cooling was effective in various years and essentially from the beginning of the period of full foliage, thus indicating that transpiration is the means by which air temperatures affect thermostatic cooling; that the ‘‘true lag’’ periods were here usually the same as for high- and low-temperature pe- riods; that direct insolation was a factor in the cambium tem- perature at times but at most a minor factor which could not be clearly detected in the center temperature. 8. The problem of ‘‘lag’’ throughout the records is dis- cussed. It is shown that the intersection points of the air-tem- perature line with the tree-temperature lines, which are de- nominated ‘‘iso-thermal nodes,’’ are important in analyzing the records and in determining the reasons for the ‘‘apparent lag’’ of the tree temperatures behind the air temperatures. The Јав”? periods of older writers were of very irregular length due in part to incomplete records and in part to an apparent misconception of the factors affecting lag. 9. While the air temperature is the major factor in determin- ing the broad limits of tree temperatures, its effect is greatly modified by various factors, some of which were discussed in preceding sections. In addition to those, the following are con- sidered: the thermal conductivity of wood substance and of water and of water vapor; the different specific heats of water and of ice; the latent heat of fusion of ice; ‘‘free’’ and ‘‘bound’”’ water; and the osmotic composition of the cell sap. The tem- perature of the soil water apparently had little effect in de- termining these tree temperatures, and it is doubtful if it is ever an important factor. This conclusion applies also to the flow of heat from the soil through the tree tissues. 10. The stretching of water columns and vaporization within [Vor. 26 236 ANNALS OF THE MISSOURI BOTANICAL GARDEN the tissues, both due mainly to foliar transpiration, are sug- gested as the main, more or less eooperating, causes of thermo- static cooling. These are considered both in light of the factual physiological and anatomical evidences and of various theories. In general, it appears that stressing of water columns may be important in the young wood layers near the cambium ; and the vaporization process especially important throughout the pneumatie system, whether permanent or temporary. The dif- ference in the vapor capacity of the air of the pneumatic tissue, due to differences of temperature, causes a direct thermostatic action, as well as having a modifying effect when the transpira- tion rate is changing. The hypothesis suggested is believed to be adequate and no other at present seems to fit the known facts. 11. Some suggestions are made as to the possible relative im- portance of the main factors in influencing tree temperatures; the special value of this method of investigation as applied to certain other important problems in tree physiology; and the possible protective benefits which the plant may derive from the temperature adjustments studied in this paper. REFERENCES! Craib, W. G. (718-'23). Regional spread of moisture in trees. Roy. Bot. Gard. dinb. Notes 11: 1-18. 1918; 12: 187-190. 1920; 14: 1-8. 1923 Gortner, R. A. ( a Selected topics in colloid chemistry. Ithaca. ——— — — —, (738). Outlines of biochemistry. 2nd ed. New York. Hartig, Th. (73). Uber die Temperatur der Baumluft. Allg. Forst- und Jagd- Zeitg. 49: 1-8. Ingersoll, L. R., and O. J. Zobel (713). An introduction to the mathematical theory h Lange, М. A. (737). Handbook of chemistry. 2nd ed. Sandusky, Mich. Luyet, B. J., and E. L. Hodapp (738). On the effect of 4. shocks on the congelation of subeooled plant tissues. Protoplasma 30: 954 MeeDougal, D. T., Overton, J. B., and Smith, ©. M. (0). The dicem -pneu- matie system of pie trees: movements of liquids and gases. Carnegie Inst. Wash. Publ. No. * A complete historical summary and review of the work on tree temperatures is in the course of preparation, and only a few, selected, pertinent references are given here. 1939] | | 237 REYNOLDS—TREE TEMPERATURE AND THERMOSTASY Mason, S. C. (725). Partial thermostasy of the growth center of the date palm. our. Agr. Res. 31: 415-453 Newton, R., and Gortner, R. A. (722). A method for ^ um ТЕР eolloid condo of expressed plant tissue fluids. Bot. Gaz. 74: Pfeffer, W. Trans. by A. J. Ewart (706). The physiology i ici Vol. 3. Oxford. Primtiey € Н. (732). The growing tree. Brit. Assoc. Adv. Sci. Rept. 1932: 185- Stiles, W. (736). An introduction to the prineiples of plant physiology. New York. [Vor. 26 238 ANNALS OF THE MISSOURI BOTANICAL GARDEN T ШЕШШ ІШІ |! ЧЇ ИЛ M TUR ІШ ІШІ ІІ ІП | Du ч ШИП | | ү ШІ ІІІ |; | “Е - Ez STUNT = | " ыы ERE 2| VN «ААА NM m il M ШШШ ү ШЫ d WM i н | ШШ H КЕГ ШІ | || Т | ШЇЇ ~ ШЇ | ill imul M | = — Е E à | ШИШИ Wn ШАП | 4 ШІ ИША Ш А. ТШ | d ini, ШИ ШШШ ИШ LUE ll || АМ И) [Кш уи ШИШИ M NDS ИНИН ИШИ ҮШҮ n IN ШІ ІШ | ШІ M ІШІ! А ІШІ Y. | | | dij i | | Hl v 111 ј ІШІ: ШШ ІШІ BEES | Va = 4 ШШ | || cM BE ШП ШШ ill ШІ ІШІ {ШЇЇ | ШП ҮЙҮН м. ІНШІ mn ТН ПАЛ ШШ fa ШШ УШ e > | | otim 1. шүр ШІ if Ш | i |5 | | PSI TL + T ЛШ ШШ Mí ТІШІШІ | ІШ ШІ A ИШИ ШАКИ ү “ШШШ ІШІШІШІШІШІШІ PHP UP ANA lN ШЇЇ ША " (ШШ d -\ И | mu AAT 11 (ШШ! M [ШШШ ШШ ШИШИШИ ИШҮ | теше ШІМ ШЕТШШШШ/ (ШШШ ШШШ ИШИ iit ү т) ШІН у ІШ ШІНШІ | Ww UR НШІ ІШ ШІ До ІШІ ІШІП! TOUR ШІ iei M irt | ШТА А АИ ІШ ІШІ! / no Е | ШЕ 2. md | 4. a ==" НЕЕ“ Ее ===> = EEr tma amem тамаа ит co Pme ABEL). FA, Виши m osa | и iu | ШИИ ШИШ =: === === = == coe = ER — == E | ІТ | ШШ ШШШ! ТІГЕ SSS SS EL = жш = = Aum. === =< z= = == = | == = > E mi ==: == == == === == ШШ | | || | D PIA ШЕ I su КЇ! ИИ ППІШІІІШ ral m ШШ ШШШ ІШІШІШ и ШШ ШЇ ЇЇ) ==> ™ ШИШ | mie ІШІП ИШИ |] АИИ И ІШІ ШІП ҮШ ДЫ ШЕШІ ШШ \( ШШ НЇШШ ШИ ШШ ||! || n АНИМАЦИИ DHL ҮШІ ІШІШШІШІШДІШІШІШ) Ша ШИИ | || | | i | | И Ш НИ ІШІ, | ШШ МШШ | er Mull ТТТ) ШП үл ТШ | үз ІН || A | JM КИ ИШИ ИП ШИ ІШІ WI DN А АМИ ui ІШ ШІ | x ШІ. ШІ po ЈН ||| ||| 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 239 ШІШШК РЕ! Ш ШЕШ И | ШЙ || (ШИГЕ ШШШ ТЇ | | ІШІП ШЕШШ ШИШ) (ЕШШ! ҮШ А | Ha ~ | | | | i | (ИШ! | ТШ ШЕ у поли Т ТИ | ‘Ta АНА (ШІ MUI M | s ШЕ ІШІ ІШІ! ТОТУНУ АИИ | AM ІШІ ШІ ІШІ ШШ И ill Wn ІШІ ШШШ ШЕНІ ili HT] ШШЩ ІШ ШІ ШШШ ШІ ІШ! ШИШИШИ ШШШ [КИШКЕ ШШШ ИИИ! ШЕТ ИШ ШІ ШЕШ Trin ВИ ШИШ ШИШИК | ШІН ШІШІ IN (ИШ ШШШ ШИШ ШІНШІ! ЖИ ШТІ ШІ! (ЕШШ ЇШЇП HAUT ARORA’ | | | И ЙЕ ЕИ ЛҮҮ | in ШІ ІШ Ш | ШШ ӨШІП! ТАМ |118 s | АЛА ИЦ | "Ul M Ини DM ИИ! S ІШІ TE УШ ШЙ ТП | || | | ПАН d TRUM LULA ІШІПТІ ШІ ІШ ишин "HB tat ІШ (ТШ ANM "ПОШ ШҮ nma n ИШИМ HUNE I DO DUE OR UL ERAT ШІ! ІШ |І Pa ШЕШТІ ІШІ an dec i (ШОШ put ВАМИ c iw "ald " (М ui il ШЕ! ШЇЇ ШЇЇ LR УУ АРА А ПАДА | ТІШІ ШШШ s URNA " ІШІП ІШІШІШІШІ ШІШІ ү! ШІ: if | m n ui ee - | DU Р ШИШ ІШІ | МЕНІН ІШІ ІШІ ННІ Ш i LM ШҮ ү. || ШІ "M ШИШ ҮЗІ ШЕШІ ШЕ НЕҢ ШШШ ih ШШШ r M | | ПК ІШ ІШІ ШІ M ШОШ ҮШ ШШШ ШИШ ШИ ІШПЕ АЛИШ [ШЇ ђе ШШШ || ШЕНІ, i h Ni hi ARAM ES ТІ) Md И ud ІШІ || ІШТІ ШІ ү! ІШ Т MUT " un jn | { ҮШҮҮ | | | || | ini ТООТ um PR , ү 1 En [ШИШ | ih ИИТИИ | ge sil Mi ҮШІ m | | ІШ ТШЩ АВА ІҢ ІШІ Ц | | | | || || || | B ШШ ШҮ LUN ИШИ li mai ІШІ Ж ШШ | | ШІ " ШІМ ТІЛШІ depen МИНИ ШЕШШ) ШИШ | | ШІ ШІП ШШ ШІ | ||| ІШ ШІ. q^ ШШ ШШШ ШИ || | | | ІШ ТТ E mo ШШ ү ШП! ГІШ ІШІМ | ШЕНІ) tH TTL | Hh ҮШ | iin || үп Шш ІШ ІШІ ІШІ |} ІШ Wt ІШІ т | | | | ІШІ || ШІ ШІ! n ІШ ҮШ ШШШ ИШ ШШ ҮШ! | ОТОО ИИ || FTO. M + iM AREAL ІН ШШШ ШИ ШІ ШЕ ӨШІП ІШІП | || ІШ ПИЦА ШІ - И | | | || | || a а] 4 ШІ Е ол о | ІНШІ ІШ || tems li} ШШШ | ІІІ ИШТИН О ІШІ | i 1 ІІ ||| (ПШПШ ПП! ll i | Т | ШІ DTE LI | ШІ 2 n ШТІ) ІШ ШШШ ТИШИ | ETN ТИШИ ШТІ | n МІН ШИН ШИШИ fign an LR wait. А | TAPER UL UE ЇЇ ШИПИН НЕ emo ND pens ШИШИ ІШ ЕШ АНТА ИЦ ІШ: STAT i E Т ШІ: UN i ІШІ Ж ШШШ ИШИ ИШИНЕ ПШ ИШТ || ШІ ШШШ ШШШ ДАЛА ОЛА ШШ ШШШ ШШШ | | bu | m -f СЕЕ АТИ E ШІ ТАМЕ Lew ШИШ ШО ШЙ ИИ АРШИН ШИШИШИ ИШИН! [Vor. 26 240 ANNALS OF THE MISSOURI BOTANICAL GARDEN Pu: il биык | ШІ ПШІЛІРТІТІШІШІ | || i Ni | И p) Ш | | aene b LIE BT ПІШШ i AR ІШІ ii D i (ШШ ІШІ di i ШШЕ ШШ ІШІ ы ІШІ ШИШИШИ И || ТІ ІШІ! | " "^N Tun NEN АІ "iln А | ІШ ШІП ІШ ШІ T iela i ІШ i | | ІШІ || ШІ ІШ EK AI PS RAI ІМ " ІШІ || ШШ ШШ Mi d iM it | ! ШШШ! E UNA T и ШІ ШІ (ШШ ! M ii (ШІ || ІШ = || ) | aM paet ШШ E | i ia S inim if ТІ Т d | и ІШІ ШШ A ШІ ШІП ШШ \ E ШИЕ M ШШ! AAs ШЇЇ ИШТИ ПТ ІШІЛІП HN A ч. ү | meee a МИН ПІШІН ү [Н М О ee rs ү E. | our NI | | n ПШ ҮШ 11. Ia | ҮШҮ || Іші. ү)! ү ШШШ [ШЇЇ ШШ ШИП, "Um ШҮ 2.2 ШІ ШШ AAA | ПП = ЇЇ ИШ 1 hes ee oe ШІ WARE 1 ІШІ ІШІ n || "n | ШІ ШТІ: Ff ЇЙЇ || || Bu ЈП АВИИ. ТУТТА ШЕШІ ШИН ШҮ ЇШЇН ҮҮ ИШИ ҮШ ШШ Т iwl и | beber UNT ШШШ ИШИН 1. M WEBS BUE i s TU na ІШІН! dE. | ЛА 11177 ' ШОШ ШШШ ИШ ШИ ү i CP ті abi p | rte ЦН ЕН 17 ІІ ДІ ШЕ or a 1 ESL ы-і |. ШИШИШИ ШИШИШИ ii | ТІКЕН ІІІ | | | И ТИШИ | ИШ mop a на ie | ІТ | МШШ] ШШ ШИШ | ІШІ a fal || i ОЕ ОЕ и Е шшш ШТІ ІШ ТІ ae in ШІ ІШІ iv ІШІ lij n ШТ Т ІШІ ЇЙЇ: ІШІ isl ШИ |! 1 | ШШШ ШШЩ h | |, и N SU E ШИШИП (ШИШ! ІШІ | ШІ ПІ "d АДАД ul A ТШ А an | | | ТАЈ МИ ШІ А АИ, ІШТІ Шеш in Г n „| "e ims ІШ | | ih ! үн ШЕШ ШІШІ RET | os ҮШҮҮ "i Д || ЇЙ. ИД | ШШ! | | m HE =f = | M ГУ ГИШИ ҮШ QUAM | all | | NT am ШШ 1 || A li M || НИ: ШШ ШІ M |n ү , ШИШИШИ! m ШІ ІШІ ШІ ШЇ | | || ue | | | ИИИ ШИШИ | АТА АТАЛ | | p ШИН ШЕЛІ | Me A | | d M MIR ІШІ Т pee Mi үү ИШ ІШІ [———i— ——] _ SS —— оа сирре =) [ тте И, == а _--—:—- REYNOLDS—TREE TEMPERATURE AND THERMOSTASY IPSUM Базен MEG. өрте i II 14% ч - + кесене ~ ceo _ шз = == ЕЕ РЕЗ ЕЕ zam n - aa ae = -— -pi r ise p I - [эшш Шш >С Dum сон. СЧ Пре ж TN EE ON TURO у ---4 р d — m =: = жй. држе ПИЛИ ан јр Г Е Е Е II ЕЕ = ПИР ом жиа -- я че. Гару | л игла EIL peo BELLE Ескене = — | сезе IE ЕЕ = з жт шз анны ы n; гач Еа amen vid ЕТШЖЕ » aR WM AR ылас оын Ee заг aS icm ПИК УНЕ eS oo сай шешіле = === == == == = = =н: f Tae - ЕЕ SSS === = =< | ы $ s i IL = А 57 ie CE Be SS Жл. С шї Жз мышта ТИСНИ; СЛАНЕ CIE оны: ЕС 7 Ла. ТӨЛ ETO oo сала Ше гасы ш э ЕЕ PI = [—1 =e sz ЕЕ 9 = Ма = = | ее" E zz a А pur a LONGA XM CHEN TED = ыы = ЕЕ 4 ЕЕ сан: ашыт қиған ик — исо Әсілі MENO ташы << =a ч Д Ея ЖЕ: a Е ЕС yee RECS SaaS <= ==" === eee: Чер D [Vor. 26 242 ANNALS OF THE MISSOURI BOTANICAL GARDEN ІШІНЕ e il | 4 | pu 1. ІІ Т Wi === клика се === = = =_=: ЕЕЕЕЕЕ ЕЕ ЕР | | ті ina eT n ШІ Wd ANNA | ПІ ШІРІІШІШ | SSS Se шшш | ! ТИ!!! ИИ EHE || \ | B ~ | | e ii \\ Е=ЕЕЕЕЕ ЕЕ Б БЕ SE е Е ІШІ Т | d ү an qu cr 11. HE 11. 2E nox | ie 11, | 11: ir LE ШҮ | T | "| iP RA M | ШШ т 2171. 2. vus | | кл | V ІШІ i ИШИ ШШШ Ш | HHH ШИД il ШШ ШШШ | à ШШШ Ш 1 ИШИ ШИШИ: ИШИП ШШ! | ІШІ) " Tl ШШ ШШ ІШІ Ш A || | || ІШІ АНА НЕ ІШ ІНЕ ШІНШІ: M ІШІ ІШІ МЫ Г wel 1. | du mu ер ШШШ ni ШИ ІШ Е a ІШІ ПІШІМІ! | tk LARA ПП Ii ШІН HUI LARUM || ІШІ ІШІ ШТ ШИН ІШ ‘A tt | i DUARTE RI | | | | | ү ІШ | "f Ui | | | T : үү оре | Mi il ИШИ A | nom Оу ИШҮ Т ІШ (ЛИТ ЙІ || | | e 1 i гиа Ш | | p АЦА Т ү ү | ||| Ll m qae || ү ШЕШ ИИ T ІШ ШІ Ш Т ШІ ООО a ТШ ШШ piii ИИ ИШИ ШИШИШИ ҮШҮҮ Wil MALE ELTE ETEN in ИШ | " ИШИ ШИШИШИ | | Е. E 11 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 243 ipeum i eA ИПИ ШШШ HL [ШШШ ШЕТ UBL ШЇЇ | ШШШ ШШ ДИ ШШШ ED о || (ШЕШШ ШШ! “ Шш un | 1512!) лан ШІЛТЕН ИЕ А RE ШИЙ [ШШ ү АЕ Шш M | n | ШИН ШИШЕ ҮТҮ ИШ, АЦА wn T | ШИИТ ИШИНИ (ШИШИШИ 10. | | | [ | т пе дим АНА пети А ШИ ШШ на ^ ІШІЛДІ | , i Mu | ШІ ІШТІ ІШ ШИШИШИ ШИН ШИШ ТШТ при ТШ. ИТ. | | war UEM mm ІШТІШИЕ 1:71 ШШШ ШИГ Rac RB ШІ 11122 АЕ ИШИ pom 21 МІНІ SM RR A M ШП ПИП! M My | ші ІШ E ШШШ ШШШ ШШШ ХАИ | ЖИШШ ШІ Ld == —— ш ЕЕ = = шах. IL LL = pt =; = = =: == == 22 с шш 2—22 Pe 2.33 E p TERMES жишш тұрақ тн AME Сус ee Ст АЕ ЧИСИ. —XEX СТТ 22. ION жиа эшек ыл Сос сыз ва яг || il | SOUCI PUN | И Wa ШК | ТІП | А [ШШ ШШШ ШШШ ШІ | ШШШ ШШШ ШШШ | ШШ ШЇ ШШШ ' ; ШІ = ШШ ifa n | No Hil :| | | || ІШІ ШШ | ШШШ | ШШШ ШШШ ШИШ ИІП li UN ШИШИШИ ІШІ ИШ ШШШ, ШЕШ ШЕШІ | ee ee "EE === аан 4 (Е-Е ЖЕСІ шик: женя иси LO ЖО ғғ ен я «с» ee SW GIO с СК гї жаза X XI сш «жан to LAU EI I жекс ILE Е ытай ыдан === = -- == ЕЕ = = Шис “=~ 2 — p E === == = = = = II = == I L—1 - = а. А 3 === EE. == ЯМ SUR M Ш ІШ m | ШІ уі ШІ ШШ P ІШІ Midi ud | ШТІ ШЕШ үй | || ү И ШІШІП | ШИШИ LUI LUE DORAL PRU | ИИИ | | | =. ^ 5 T 3 = шыма г oe oa жан LXI a RC кк «Ежа шз тшн шош ІШІ АЛА АИ ЖИТ | ІШІ ШІН | Mi ІШІ) ІШ = К пир = =a ШІ) | i | i P ШИШ BUR | | t Ы о та же аша: сива ma nani TM ІШІ (ШІ ШІ [Vor. 26 244 ANNALS OF THE MISSOURI BOTANICAL GARDEN аг Ma || | 11 ||| || F ||| ul e * OMM АШ ИЦ) Mi [и ШШ үү TE [КЕЛШИ (ШШШ! | N F [ШШ (ШШ [^ || ‘mi WT | | ҮҮ! ШШ || ! ||| | | ІШІ ШІ ІШ Li | || И = M ІШІ | ІШІ) ТШ 11 \ M | Т ӨШ | | pi | ТШШ || ШІ: ІШІ ІШІ | i ae MM n || | ІМ | | ҮШІ EE | | zi ij Hi gu ор ШТІ) ВАТ: | illl Т ДВАМА ОМ АЦА DR ШШШ 4 eee Б | Ji | | ІІІ) 117 ШІ | T il MR А ШІ ШШ В" Ir ІШІ ТЕП n ШІН Eu EXE и ЧИЕ SS Ш == ШШ ШП ШИШИП ШЫП tm ШЕШ T (Nu тат Тото") ІШІ ШШ EAM | n e ШЇ UU ] ШШШ НИ 144 ІШ ШШЕ ЕЛ |, | | ШИШЕ ШІ Ue ШІ ==} "ЕНСЕ san кэш -- 1—3 == z= MEER К-т сы, сг | i | | үү We | Ш MES Ti | nd | НЕ || i Ni ИМАМ ТАМА Mi n " ПІ | | | қ E H ІІІ I Па | | үү e H 5 | 1 11.2 у | ИШ ТШЩ ШҮ 1. | ғ | j | а | | | | Tu 11 || ы 1 ІШ ы || ШЕШ ІШ ili bs | || ГІШ lh | d | ШІ | | ү i ІШ il || | | | | ІШ | | | | | | i | UA ыы быы ы —-———1-— 1 : a EEILIUERI MEL ІШ | | | ШІ | | | | ШІ Ш ШШШ PH ШҮ | || TAE LEO | 4 [z. ју · ||| ІШ Hl Т || m | nil ПІ Ж ТШШ ||| || I: ind И ME | | || I | ШИШ ІШІ | — Se ДА МИН | ! ІШІ II ШТ ІП ИШТ ДЇ || BALL. "ЧАИ || n ШШ ШШ ТІП e SS oe шшш» _ Tee ee eS ES аа || | | ІШІ ШЇ ЇШЇП illos! ТИ IT ДА А АШ i | | } | || ШГ ҮТҮ! Eee НИ || | || || | = — NM LI IE pana aas pec ama = a ЕЕЕ ЕЕ f == = =e 1939] TREE TEMPERATURE AND THERMOSTASY 245 REYNOLDS == x =“ a о = жиа Е ваа SE В МНН ee = шіл Е-Е ee ee mecum. эшет. ај TT шшщ ша у= [ee SS ЕР АЕ E MI (Cw жыпы COND a жаа oe iata pf | р c= 2-І 4-3 Ld ЕЕ жайы лет ита | ee ш SS шаа: тш TS MENS жез ЕЕ ЖІ- хі- ст с MAT жы к=: EE inde = CILE 1 жен лесе әлі: ЕЕ 1 E EI a SS ———_——= 2 — = ЕЕ = = a еф: о". - à ESAE = aea — == == = == = жЕкЕ ЕЕЕ ЕЕЕ о o o : Жасты ЕЕЕЕЕ SSS SSS ESSE = ЕЕЕ е == = с ір SSS SaaS из. << јр T \ || a Am ili ГТ 5 есі rea Алы ыж. глн ee NU ee ee medii = Е жазы; - = ~ чаа н x = +e. : — | i -________- || | а ІШ TAE — = - —— н - MM паз Бш жок ус шшш?” ш ыш IL ——— ——— a ь. ЕЕ —1 ees Е: -e шалын À р [Vor. 26 246 ANNALS OF THE MISSOURI BOTANICAL GARDEN EV 4 Ed | "n d г | 5 ас ШІНШІ mU | | Um D n uw E p ig ШІ P ІШІ mu d i M 17 ШІ ІТ i | АШ |. ІШ | J MI ІШІ ІШ Va E Ц T : | NE | E | | || ІШ n a ІШІ i г ср м ЕЕ ————— | | | t y | | || Ш | | ~ ІШ i |қ ы: p " | ' ЕШ | n | | | ша | ПИВА ШИШИШИ |' n" | ILL заж ки Җи 01 С-и O REEFS аа --------І- о Se Se SS SS SS SSS === SSS SS SS = = == ESEE Ш | TE || {Т ШШШ ШИИ n ІШІ ІШІ i i i | ү ШЕШІП Г | | | | 1 | | 111. i ІШІ i ү || ТИШ иии | T ii Т | | Е | T ec it d ІШ | у ИТ, a | ІШ ШЕЛІ LL л Гү | || ||| ||| у Уз: = | ү. === === d ШЕН — | || ІШІ |. -— на: LLL - пи ------ Losses ше» ЕЕ t | i t ПІ MENT MATE ІШІ | ү MI, || | / | | | Mu ІШ 11 1 "xd: | {| ү ШШ 143 | B ii ШІ | ШИШИШИ И ҮН al ic ШИШИШИ ШШШ! (ШІМ ПТ К ҮШІ ШИШИЙ) ШАШ НИ ШИШИ! ІШІШІШІШ ШЕ ШІ | | ШШШ V | ||| ү ||| " | г. | | | | = n e demam аң E LEES Ұз | LE Ld T lm = ЩЕ o AUT ШІ | || jil || | 1] | - itt | т | -— гони веш | JE о АПИ "n ІШІ ИНИ Т "EM il ІШ ІШ d | ІШІ ҮШ | кр | n ІШ | ІШ ШИИТ г ШТ | e ТІ ШІ " n ШИШИ ІШ ІШ Т ІШІ | y ү "m 1а SM a ҮЙ | | ТШ ll 1939] REYNOLDS—TREE TEMPERATURE AND THERMOSTASY 247 ||| ||| TR И 1 ШШ ТІШІШІ li | | ШІ | | || А Ш d ІШІШ ! | Mili | ҮТҮ + | | | ШЦ/ M | ШІШІ | m i ІН Ab ШІ ІШЕР Hit ii | | | | | AM ШТ T | ШИШИТИП ІШІ ШИШ || = 111177 TM 5 г == == SS 5. ШШШ ТШШ | (1 \ ТТТ ИП | || T ЈЕ | Е 4 || 1 UN | ) || ТМ LATERI ОШО ТАМ ИР BUD | р | mm ІІ! | Н Hr ||| | | И | HIN ШІ, ІІ ||| i | ||| n ШІ | | E | t | ІШ ІШІ ІШШІ ШІ на Wil: ЕЕЕ D "== ІШІ ШШШ | ШШ Mi || ІШІП |, MEI || ү ДЦ Bill ІШІ, || | ШІП | ШІ | ) | ШЕ at ; | | а тыт ала wi» Jusumpdiiqm eme | == == == ---- --- WR —E--—.— i elsi = Е — SS === === = > = = == REUSING EE = = zm L = SS SSS SS. == 2- = » € > 4—5 Geen Ss SS аша == a Pe: р —— p cS “е сылар айтай с трена. iem == ЕАМ EEERERS т Т | T. y = ІШІ (Еш ІШІ E-————-——-— === саси "IB Ai нини Т Wn NA ҮШҮҮ ШШШ ШИШ ШШШ ШШ ІТ ІШІ | ~ ШШЕ === rrr — E ЕЕ EE к====== == = ЕЕ = == = ТЕТЕ a ua m amu amen <В i = = d ІН ||| НИИ ШТІ ШІ | [ Hi | EB | ЕПИ n ШИТІ | —— AR Баға = SS Se = 2S SSS SS SSS Se SS : 2 || | d В | [| n ШШ | ill i | ү mh = Е ЕЕЕЕЕ EX EL So ee SS SS SS SSS ҮШ BARN UP dE a: UND Вара ЇЇ ЇЇ ШІ! 17 ge | | | | || Y. | м! шаша кш — S= S= IIT aS ere = LU p шеше іе ҮШ! ГТ "un ІШ | ІШ “ШЛУ =< 4 < o нв == > ==> -a _-------=-=4 248 - REYNOLDS—TREE TEMPERATU HERM 249 MIEL oa де ти ТІ ІШ [ҮШ ү ШИ | | ҮШ ШІ | ПО. АШ ||| || ШІ DN LUN | | НЕЕ. nam bu NA dep E Ш id Mul | | ІШІП ТҮҮН ШІ || is Ji | 21 BE. 174777 ue | ШОШ р ү il 777 = 1" i Vs Tra ҮШҮК eic || Pup 41 TUN I ШІ || ШЕ Н НВ 1 |! y ji Т || | | ІШІ | 1 АЦА ІШІ! 1! || ІШІШ | | [| | | | i QU DNA ний ШІШІІШІШШІ || | ШШШ | ІІ ШШЕ ШІШІШІ! (Ый ii d ШШ || | АИ | || | ЙІ ШИШ Er um c pam Ri yoQ m c I ТОПЫ dl E" ү 2. А e TN M i | ІШІ А Ц | АН || TURA ААА 1717 UN ш ш ү шош ce Е НИН eu Ш М» ИШ il ||| | |: | | | ІШ | Ш i ШІ ІШЕ $0 mam. | pp i ІШ ТТ ІШЕ ШІП ||| 1 ||| || НШІ | | ИШ ІШІ ҮТ 10 TR И ШІ ТҮ ) | [| iN ІЛ ТАҢ "MEUM, | ИИ mc m к c т j| ЕМЕ ! Ee в): Ex | | ШШШ р 1 Ej me 4 uc RM P nu CE i | Cem dom. щы : | | z Ly К. ШЕ. | P ya ЖИ 1 ay SS = Е i eg i > ге SS ЕЕЕ Е те ЕЕ ILLE SSS - EE =>= —— == "3 ai ESS Ro на — — Img = = m = Z =a SSS S=— ча IBI YNOLDS—TREE TEMPERATURE AND THERMOST 251 | рас ІШІ | | | ТІ) Ш 1171 Wie vem deus m | n | ІНІ | TRU W ac А ТК 4 Е ҮЙ ШУ | D | ыы ТШ ІШ | Т\Ш! d T [ШИ ШШШ ИР ера ҮЧҮ ү || т. ШІП ГҮҮ Mx Т ҮҮТ! | ia l |, | Na ИЙИ ИШИП | ІШ Y | | | n | ( ТІ uu || m | | | | Uis i 2 | | 7 ( = === == с=ш= шс B. —————FE- Omm ЕЕ = — = E НЕЕ G ==———= ЕЕ КЕ ЕЕ —— M со е BS = === није SS SS Ss ee к n етеш жааб E — — — an 1 a ЕЕ ————— Ж — — 5 m3 уагда mE |] - i - A SA = ~ == == = - = = — ~ zi = = а = = 4. e 3 A ~ = == Ер Е == ccm m = == m == = =] = 5 I t — MI IL == ==: ЕСН Epp—— ÉL——————BR— ЕЕЕ НЕЕ ЕЕ бек ЕЕ = = ЕЕ SS SS = == = = ee ESS SS SS ——— Еа аі P SCN === = SS SS == E ————— || nh iy ||. y DE i ШІ P / ІШІ i ы "E i idi Е eem = Elm et DERI = кше Е ee. [— == ы) ===. = Rc See ВЕ == ЕЕ ^ =з с =_==к= É——Ó—————————— ESS ЕН == у Т у == 1 је SS SS e SSS Vor. 26 252 ANNALS OF THE MISSOURI BOTANICAL GARDEN | ТІП ІШІ ИШ | ІП. ni ІШ ШІП UI VATA ill ШШ ШО ІШШ JM M ІШ | im | li у ШШШ! (ШЕ | | | ШШ | ІШІ il ҮТҮ (ИШ ШІ "n d ІШ ! || ТШ i ІШ ("И Wi ННИ I Fill ПТ ШШШ O ШТ | | ІШІ | m ІШ et 4 М || VIUA A i 0 А ИШҮ (ІШ | [| ii Ш B QUUD ІҢ ІШІШІ ІІІ HAAR ПНИН | » (|| | | т ШІ | Hm || |! КЕ! | ШИШИ iM | | ШІ | ГІЛІ ШТ ШИ ШІ ШШШ = | 4 1 | a o) MINE а. ҮП RE И. \ | | ІШ | ҮШ | i MM DU LAG ИО ШИШ | ІШ ШТІ ШИН | iB T. м ІП ШІ (ЖЧ! ШО [| УШ | y | E ЕН АЛА АДА || ИШ jn ОН A ШШЕ ШШШ Е: EE S= БЕ ESS SE ESS SSS = ЕР LI ES = ЕЕ =—=—_ с ===“ ІШШІШШІМІЕ | ІШІ im ШШ ү, || ШІ | | | || 11 ili ||| ШШ | "АИ АА ААА Ш (|| | | ІШ ҮШ А | | dil Г ШҮҮ ү ECL miss (Т || NR | || ү i Г ||| ШЕ ІІ) ИІНІ! ү ЇЇ MT UR 1 ИШ bout ТІ n MAH | ИШ! ћ il | M И; || | || | ҮП ||| il ІШ at " Y | ||| d ШІ || Шегі M А ШІ i || ПІ ТИІ " ШТІ реми ТЕП ~ ERE E mM 1: BIS UE. АЈА TA | | || ШШШ ШЇ ШЇЇ | wes ||| n | ІШ | ||| ! ІШ MI ШШ | M8 "AMI ІШ | ШІ mi ІШТІ MI ШІ ШІ ЇЧ | | | | ПИ ШІ ІШІ yi ! ІШ | ІШ А | | ІШ 14 Mie || p ИЦ. | | | | || | || ШШ! | TIME D ESL ES ШШ TURN LERRA AN | I | RH ETT Ү || I 1 n EMI | | tt di m ||| | ИИҮҮ ШИ (ШШ ИШ! lii NM TAM ME | E ІШ ПІШІП: | ШӨПТІ | || | | | JONNY N || nu | || | | ІШ | ИЦ | ТШ ІШІ Бына | | | ІШІН ІІ | | Ни + М | | rn ШІ ІІІ ІШ " TM aU ІШІНЕН ПОЉАНИ ШШШ | = | | | Е | li] || | ІШІП ES | um ІМ ІК | T 1. | | ||| ШІ Md ШІ ІШ А ТЕ TENIS ІШІ! ШҮҮ ТЇ al | Bom || | | \ ү ШІ ШІ || VI [Vor. 26 MISSOURI BOTANICAL GARDEN ANNALS OF THE 254 RES | 7 coIEGILALUL—EL—IDILERLDIMMECCLCLEELLEZC——LLL—-—E-——emgt--——I-———E SS SS ES ES ЕЕЕ SES SES ESS ааа ааа а ан ааа = LS ЕЕ Imm == == ЕЕ ЕЕ ЕЕ ада ТЕ Е SSS SS SS Se SS SS SS SS SS SS eS ES SS SS SS Eee == тү тесті = 4-ға SS ЕЕЕ: с = па ИЕ іе Е-Е ы. ЕЕ === = ЕЕ пе тнк к ыы уы SSS ЕЕ ЕЕ ЕЕЕ L == SS SS E ee eee ee ee SEE SSS eee RUD E а Е р meti $m tn ge E E ЕН: Е Е Е 18 ee ee | M_a EE --. —— Lak [oen quot ee roit mmi ma й: га I I ze ЕЕ ы Еа ыы ыы AE === ЕЕ рр e E = 222 ЕЕ: ЕЕ === ЕЕ Е ЕЕ SSSSSSSSSS—_ Е ЕЕЕ SSE ааа аа ааа = == == == SS СЕЕ ЕЕЕ ЕЕЕ = Se ee ee. a SS ee tr т ЕЕ ЕЕ шшш = ЕЕ SE ТЕТЕ цев ___ ЕЕ SS SSS = << SS SS ES ES ESS е м-гі шы 3—1—F38—:1—:—:-—— 1 = Ей _ === = 5 Е Е чш EE SSS SS SSS SS SS = Жы SS SS SS EE = = EI 2S S$ SS = SS SS SS l LS SS = ЕЕ T SSS SS SS SSS ESS == ЗЕЕ > pS = =з 3 | | == 2 г = a == СЕБЕ шошо шш иш ш мы ЕЕЕ ЕЕ SSS" SSS SS | | | | | | | | | | || || а ранена арра ТЕРЬ = EES араа Е Sn a e eer e ae нм” “Ч. - „ри 7 eee eee ee "==; Е-Е SSS SSE Е} Е + и ке S= = ЕЕ ==: z= — — + - ——2 ~ ~ = — 2 ee SS ЕЕ: ЕЕ Е mm: - Ше Ес шш SS SS ааа ЕЕЕ Е: === === | | | | | | | i | | i | 2 | | | | | | | | | | 1939] REYNOLDS— TREE TEMPERATURE AND THERMOSTASY 205 | Ji РАИ | ШІЛ (ШІП ШЫТ ІШІН» ii 417 ШІГІШШТ || ПМ ТЕ an \\\ Meu ШІ! | ||| ШЫ! EE Т E НАШЕ ТШ ШОПАН 7AM = | X ШІ ТГ ІШІ Tav LA ME 2 | |. ТЕ \ BEL ІШ | \ | ШІ a pene Ет Wi. Un | s EE IL ” а - 2-І | li mori Top perde LE 11 ДОВЕЛА Тави" | ОДАН А d ҮШІ AT МЕН ШІ ШІ cp T DES Yu ШШЕ || ү 7 B T IE a i ily ШІ ІШІ ИІ ati | um сте ШУ ШИ ША "ШИ m TU “Иш 44. үү Кү АНА. АД ШТ ШИШ ИИ АДА АИ АЦА. BULL ААА 90 ШИТ ul [ШИШИ (ТШШ “ТШ ШІП UR ФРА ІШЕТІШІШІ | ШТ ПШ i ШШШ ІШ ТА Ш NINO U (И! | TM ІШІ EUIS cee 4 | \\| 11 Eu ЕЕ" = === 2 — EL $e т h о Гек => = лаш a = = „> EET | =. IE, "WES == ‚Ж Lu | i ІШ” THE itl Га «| | Us MONI АДА DEM. i ; iii m ||| ИЛЕГІШ, i ; "ur ШІ ІШІ bcr. Annals of the Missouri Botanical Garden Vol. 26 NOVEMBER, 1939 No. 4 NEW OR OTHERWISE NOTEWORTHY APOCYNACEAE OF TROPICAL AMERICA. VII! ROBERT E. WOODSON, JR. Assistant Curator of the Herbarium, Missouri Botanical Garden Assistant Professor in the Henry Shaw School of Botany of Washington University Mortoniella Woodson, gen. nov. Apocynacearum (Plumer- ioideae-Alstoniinae). Calyx 5-partitus eglandulosus; laciniae scariaceae vel paullulo foliaceae imbricatae sat aequales mox eaeduees. Corolla salverformis; tubus gracilis basi paulo gib- bosus ibique staminigerus; limbi laciniae 5 paulo inaequales aestivatione sinistrorsum convolutae. Stamina 5 epipetala profunde inclusa ; antherae inter se liberae 4-loculares omnino fertiles nullomodo appendiculatae ; filamenta perbrevia. Ovarii earpella gemina basi distincta apice in stylo aequilongo tur- binato produeta, ovulis 12, 4-seriatim superpositis; stigma breviter fusiformi-capitatum. Nectaria nulla.—Arbores vel frutiees (?). Folia alternata petiolo medio glandulo-umbonato eaeterumque eglandulosa integra penninervia. Inflorescentia terminalis thyrsiformis. Mortoniella Pittieri Woodson, spec. nov.; arborea vel fruti- eosa (?); foliis alternatis longe petiolatis oblongo-elliptieis apice longiuscule subcaudato-acuminatis basi acute obtuseque euneatis 10-13 em. longis 2.0-8.2 ст. latis membranaceis om- nino glabris dense subhorizontaliterque nervosis, petiolo са. 2.5 em. longo medio glandulo-umbonato; inflorescentiis thyr- 1 Issued November 30, 1939. ANN. Mo. Bor. GARD., Vol. 26, 1939 (257) [Vor. 26 208 ANNALS OF THE MISSOURI BOTANICAL GARDEN soideis terminalibus plurifloris 2.5-6.0 em. longis; pedicellis 0.5-0.7 em. longis; calycis lobis late ovatis vel ovato-oblongis obtusis 0.15 em. longis extus minute puberulis ; corollae salver- formis tubo 1.5-2.0 em. longo basi ca. 0.12 em. diam. deinde paululo gibboso-inflato fauces versus gradatim ampliato extus glabro intus basi villoso-barbato caeterumque glabro, lobis oblique obovato-oblongis rotundatis paulo inaequilateralibus 1.7-2.0 em. longis 0.5-0.7 cm. latis patulis; antheris compresse ellipsoideis 0.15 em. longis; ovariis compresse ovoideis са. 0.1 em. longis glabris; stigmate 0.1 em. longo; fruetu ignoto.— Costa Rica: bois de la baie de Salinas, July, 1890, H. Pittier 2912 (Herb. Inst. Bot. Lausanne, түре). Itis most unfortunate that both the habit and the fruit of this remarkable plant are unknown. I suspect that it is rather closely related to Aspidosperma, but it is without a gynoecial nectary, and both the caducous calyx-lobes and the peculiar petiolar glands are quite unlike anything in the Apocynaceae known to me. The aspect of the specimen somewhat resembles Vallesia, but the number and arrangement of the ovules are quite different, of course, and the characteristic intrapetiolar glands of the latter genus are lacking. Тһе genus is named in honor of Mr. C. V. Morton, of the United States National Her- barium, who called to my attention the type specimen, which had long remained unidentified in the Institut de Botanique of the University of Lausanne. Рвквтохтл dentigera Woodson, sp. nov. Frutex volubilis omnino glabrus altitudine ignotus, ramulis gracillimis inter- nodiis са. 15-18 em. longis; foliis obovatis vel obovato-oblongis apice rotundatis et abruptissime breviterque apiculatis basi late obtusis 15-17 cm. longis 7.5-9.0 ст. latis membranaceis, petiolo 1.0-1.5 em. longo; inflorescentiis lateralibus, pedunculo sterili 5 em. longo, ramis florigeris 3 cm. longis, bracteis setaceis vix 0.1 em. longis, pedicellis geminis 1 ст. longis ; calycis lobis oblongo-lanceolatis acuminatis foliaceis plus minusve pur- purissatis 0.5-0.6 em. longis, squamellis late dentiformibus арісе minutissime erosis; corollae ut dicitur flavidulae satu- rateque rubrae tubo 1.5 em. longo basi са. 0.25 em. diam., lobis 1939] WOODSON—APOCYNACEAE OF TROPICAL AMERICA. ҮП 259 late dolabriformibus minute apiculatis 0.8 ст. longis patenti- bus; appendicibus epistaminalibus oblongis vix inclusis; an- theris oblongo-sagittatis 0.6 em. longis dorso minutissime pu- berulis apice paulo exsertis ; ovariis ovoideis ca. 0.15 em. longis glabris; stigmate subcapitato-fusiforme 0.15 cm. longo; nec- tariis carnosis conspicue dentiformibus compresse ovoideis basi vix concrescentibus apice distincte acuteque lobatis basi vix conerescentibus ; follieulis ignotis.—CosrA Rica: vicinity of El General, Prov. San José, alt. 640 m., Jan., 1939, А. F. Skutch 3864 (U.S. National Herb., ТУРЕ). This species is closely related to P. concolor (Blake) Woods. and P. obovata Standl., but differs from both in the trichoto- mous inflorescence and the very peculiar, tooth-shaped nec- taries. MxsECcHiTES TRIFIDA (Jacq.) Muell.-Arg. var. tomentulosa Woodson, var. nov., a varietate typica planta tota corolla ex- cepta dense minuteque tomentulosa differt—Brazm: Taper- inha bei Santarem, im Bestand der Montrichardia arborescens kletternd, July 10, 1927, А. Ginzberger 351 (Herb. Field Mus., TYPE). Recalling M. bicorniculata (Rusby) Woods., but with the floral dimensions of typical M. trifida. TWO NEW ASCLEPIADS FROM THE WESTERN UNITED STATES! ROBERT E. WOODSON, JR. Assistant Curator of the Herbariwm, Missouri Botanical Garden Assistant Professor in the Henry Shaw School of Botany of Washington University During the preparation of a revision of the North American species of Asclepias, two novelties from the western United States have been encountered which it seems well to record, since the date of publication of the complete work is uncertain. AscLEPIASs Davisii Woodson, spec. nov. (fig. 1). Herbae perennes parvulae subsucculentae prostratae; caules basi fasciculati 1.0-1.5 dm. longi plus minusve compressi simplices glabri; folia opposita late ovata vel ovato-elliptica apice obtusa vel abrupte breviterque acuminata basi late obtusa aut rotun- data aut late obseureque cordata non rarius plus minusve de- eurrentia cum petiolo ca. 0.2-0.4 em. longo 3.0-4.5 em. longa 1.54.0 em. lata inferne multo minora dilute viridia plus mi- nusve glaucescentia glabra; inflorescentia terminalis umbelli- formis 5-15-flora sessilis, foliis minoribus 1-2 subtendentibus, pedicellis 2 em. longis glabris; calycis lobi elliptico-lanceolati acuminati 0.6 em. longi sparse pilosuli ; corollae rotatae dilute luteo-viridis lobi patuli ovato-elliptici late acuti 1.0-1.2 em. longi 0.6-0.7 cm. lati intus papillati vel minute pilosuli extus apicem versus plus minusve purpurissati ; staminum columna earnosa са. 0.3 em. alta, antherae 0.25 ст. longae dilute viridu- lae apicibus scariaceis obtusis inflexis, alis aequilateralibus late obtusis integris, coronae foliolae calceolatae carnosae livide purpurissatae 0.5 em. longae 0.35 cm. latae compressae prope margines interiores ca. 0.1 em. longae abrupte apiculatae basi columnam totam adnatae, cornieulo incurvato adnato omnino incluso vel nullo; pollinia ca. 1.5 mm. longa compressa anguste inaequilateraliterque pyriformia, caudiculis gracilibus tortulis ca. 0.5 mm. longis, corpusculo compresse rhomboideo ca. 0.25 mm. longo; folliculi non visi. *Issued November 30, 1939. ANN. Mo. Вот. GARD., Vol. 26, 1939 (261) [Vor. 26 262 ANNALS OF THE MISSOURI BOTANICAL GARDEN Invano: Glenn's Ferry, Elmore County, Мау 15, 1938, В. J. Davis 85 (Herb. Missouri Bot. Garden, түре); Овквох: loose soil, high hillsides opposite Lloyd Humphrey's ranch, Grant County, April 30, 1925, L. F. Henderson s.n. (Herb. Missouri Bot. Garden). Professor Davis writes me: “Тһе plant grows prostrate on the ground with nothing but the ends of the branches turned slightly upward. Тһе stem is а pale green color, but I did not . 1. Asclepias ar” = Flower, pollinia, and hood in longitudinal ze.) Fig = (Drawn by A. А. look particularly to see whether it was flattened or not. . . . It seems to grow only on barren alkaline clay knolls. There was no plant of it found growing where any other vegetation grew." A. Davisii closely simulates А. Cryptoceros Wats. in general appearance and distribution and is doubtless closely related to it. In the former, however, the corona hoods are more abruptly apiculate and scarcely attain the anther-head which they con- siderably surpass in the latter, where the flowers are somewhat larger as well. The two specimens cited, although essentially similar, show certain dissimilarities of the corona: the hoods of Davis 85 are more abruptly and shortly apiculate and are without the 1939] WOODSON—TWO NEW ASCLEPIADS 263 inconspicuous, incurved horn characteristic of Henderson s.n. The character of the horn appears to be unusually inconstant in certain species of the western United States, notably in 4. cali- fornica where I have observed a series of intergradations from a very definite structure to complete obsolescence. Similar var- iation 1s shown strikingly in the following species as well. AscLEPIAS Cutleri Woodson, spec. nov. (fig. 2). Herbae perennes parvulae; caules basi fasciculati suberecti 1-2 dm. Fig. 2. Asclepias Cutleri Woodson. Flower, pollinia, and two hoods in longi- tudinal section to show variation of the horn. (Drawn by A. A. Heinze.) alti tenues simplices vel rarius pauciramosi minute pilosuli; folia opposita vel approximata subsessilia linearia apice асп- minata basi attenuata cum petiolo vix bene manifesto 4-8 cm. longa ut videntur subsucculenta minute pilosula dilute viridia; inflorescentia in axillis foliorum lateralis pauciflora brevissime pedunculata vel verisimiliter sessilis, pedicellis ca. 1 em. longis minute pilosulis ; calycis lobi ovato-lanceolati acuminati dense pilosuli ; corollae rotatae dilute lividae lobi patuli ovato-ellip- tici late acuti 0.5-0.6 em. longi са. 0.2 em. lati extus minute sparseque pilosuli intus minutissime papillati; staminum columna carnosa са. 0.1 em. alta inter foliolas coronae saccata, antherae 0.15 cm. longae apicibus scariaceis obtusis inflexis, [Vor. 26, 1939] 264 ANNALS OF THE MISSOURI BOTANICAL GARDEN alis obtusis integris; pollinia compresse subrhomboideo-pyri- formia ca. 0.75 mm. longa, caudiculis corpusculoque ea. 0.25 mm. longis, coronae foliolae saccatae carnosae 0.15 cm. longae dorso obtusae, lobulis lateralibus acutis prominentibus, cor- nieulo parvo vel subnullo incluso; follieuli penduli ovato-fusi- formes са. 5 em. longi dense pilosuli. ARIZONA: rare on sands, 5 mi. west of Rock Point, Apache County, June 15, 1938, H. C. Cutler 2177 (Herb. Missouri Bot. Garden, түре). This species obviously is most closely related to А. brachy- stephana Engelm. and A. uncialis Greene, from both of which it differs in its habit and narrower foliage, as well as in technical details of the gynostegium. Perhaps most noteworthy is the fruit, since pendulous follieles previously have been known to occur only in A. perennis and А. albicans amongst the species of the United States. Ei "uu ала КУ TUIS УЛ С J 4 CONTRIBUTIONS TOWARD A FLORA OF PANAMA! ПТ. COLLECTIONS DURING THE SUMMER or 1938, CHIEFLY BY В. E. Woonson, Jn., P. Н. ALLEN, AND В. J. SEIBERT ROBERT E. WOODSON, JR. Assistant Curator of the Herbarium, Missouri Botanical Garden Assistant Professor in the Henry Shaw School of Botany of Washington University AND RUSSELL J. SEIBERT University Fellow in Botany, Henry Shaw School of Botany of Washington University During the summer of 1938, from June 17 to August 20, a party consisting of R. E. Woodson, Jr., Paul H. Allen, and Russell J. Seibert was sent to Panama under the joint auspices of the Missouri Botanical Garden and the Arnold Arboretum of Harvard University. The purpose of the expedition was chiefly to recoup the losses sustained in a fire at the end of the previous summer’s collecting trip. As in previous years, numerous short trips into the interior were made from the Tropical Station of the Missouri Botani- cal Garden at Balboa, C.Z., now under direct control of the Canal Zone. The principal trips, however, were to the high- lands on Chiriquí on the Расте slope of the Voleán de Chiri- quí, a favorite collecting locality since the days of Seemann and Warscewicz, and the lowlands about the Chiriqui Lagoon in Bocas del Toro, upon the Atlantic slope. A projected trip to Darién was necessarily postponed because of the illness of both Woodson and Seibert. This trip was taken later in the year by Allen, and will be reported in the next of this series. Although it is still possible to make the trip to Chiriqui rather painfully by cattle boat, use of the airplane and the new Panamerican Highway has decided advantages. Regular flying service from Panama City to David, the capitol city of Chiriqui province, reduces the time between the two cities, from a day and a night via the lowing and odorous hulls of the Compañía de Navegaciónes Chitreana, to a mere two hours. ! Issued November 30, 1929. ANN. Мо. Вот. GARD., Vol. 26, 1939 (265) [Vor. 26 266 ANNALS OF THE MISSOURI BOTANICAL GARDEN Air travel, however convenient, has its drawbacks for the botanist. Many miles of vegetation-covered wilderness is given an exasperatingly distant enchantment. And should he be a timid soul, the wilderness becomes forbidding indeed if a precipitant descent is contemplated. In 1935 Woodson and Seibert, together with Dr. George W. Martin, had a taste of such interest when the landing gear of their plane was wrecked at the very moment of take-off, on an improvised landing field at Llanos del Volcán, in Chiriquí. Safe landing at that time was made by the skill of Robert Marstrand, the pilot, who was killed on the same route later in the summer, flying headlong into the сІопдей summit of Cerro Trinidad. Taking all such things into consideration, a light truck was purchased by Allen and converted into a cavernous convey- ance for enough collecting and pressing materials for a month. On top of all the other paraphernalia a precarious garnish was made of a number of living ornamental plants potted in tin cans and intended for our good friend Mr. T. B. Mónniche at Boquete. The whole cargo, heaped high, was covered with water-proofed canvas, and we set upon our way. The Panamanian section of the Panamerican Highway is known locally as the Carretera Nacional. The preceding summer we had made the approximately 300-mile trip from Panama City to David in an ancient, specially chartered chiva (a light bus, but in Spanish, appropriately, a goat). We found then that most of the western half of the road was either in the process of being blasted from solid rock or eut through jungle, and the whole trip required twenty-eight hours of continuous driving. When all other details of that trip vanish, the scien- tifie oceupants of the chiva will probably still remember how, during each of those twenty-eight hours, they took turns hold- ing up the windshield with their feet for the expressed benefit of the Panameño driver, bounding over the Carretera in a most unnatural position. This year, however, we not only rode in а 34-ton truck pro- vided with springs, but found to our delight that the road had been improved quite noticeably, enabling us to reach David 1939] WOODSON & SEIBERT—-FLORA OF PANAMA. III 267 after only fourteen hours. Although the road had been much worked upon during the year’s interval, the surrounding coun- try was still unspoiled, and we were able to make numerous collections en route, including several novelties. Even from the road, for example, the bright orange flowers of Tussacia Woodsonii Morton, abounding in the low woods near Remedios, could be distinguished from the rather greenish yellow flowers of the common T. Friedrichsthaliana. So with a grinding of brakes and a tornado of dust, a new species was added to the interesting family Gesneriaceae. In the swampy jungles near the Rio Fonseca the attention of any motoring botanist could scarcely miss the giant, scarlet-bracted canes of Costus Lima K.Sch., previously unknown from Panama. Not a hundred yards from the road we ate our lunch under a tree in which were twining Fernaldia speciosissima and Prestonia remedi- orum, new species of Apocynaceous lianas. Nightfall found us established at the cavernous Pension Italiana in David. Early the next morning we abandoned the truck and transferred our gear to the narrow-gage train for the trip to Boquete. The line is only about thirty miles long, but is at such a continuous grade from David, about 50 m. eleva- tion, to Boquete, about 1000 m., that it appeared to be all the diminutive locomotive could possibly do to pull us thence in three hours. The name Boquete is well deserved, for it means ‘‘The Bou- quet.’’ The town, of perhaps 1,000 inhabitants, is set at about the elevation of Cartago, in Costa Rica, and is favored with a climate that is almost ideal. With the Voleán de Chiriquí towering above, it lies in a deeply forested canyon of the tem- pestuous little Rio Caldera. Nearly everyone in town has a luxuriant garden almost monotonously filled with bloom- ing roses, lilies and delicious strawberries. Not far up the mountain slopes a native raspberry (Rubus glaucus Benth.) abounds, which is really superior to the best cultivated berries of the States. It is no wonder that Boquete is a favorite alike for vacationists from the Canal Zone and for nearly all bota- nists who visit Panama. [Vor. 26 268 ANNALS OF THE MISSOURI BOTANICAL GARDEN But the real attraction of Boquete is that it is not far from Finea Lérida, the remarkable establishment of Mr. T. B. Monniche, nearly 300 m. higher upon the slope of the volcano. It is doubtful whether Mr. Mónniche and his charming wife themselves know how many pilgrims to Finea Lérida they weleome each year. Surely in Panama, if not in all Central America, there is not another finca where the coffee is more successfully grown and handled, where the native help is more kindly and wisely administered, and where the proprietors are more gracious to all with whom they come in contact. Mr. Mónniche is a keen naturalist himself, and fully under- stood our needs in studying the local vegetation. Accordingly, as in the previous summer, he placed at our disposal a little maintenance shed, ‘‘Casita Alta," about three miles farther up the slope of the volcano, at an elevation of about 2,000 m. Casita Alta furnishes the greatest requirement of a visiting plant collector, particularly in the rainy season: it is dry. Otherwise, it is a frame structure of about ten by eight feet, without windows, floor or furniture except a shelf in the back for our supplies. А bed is made by pulling fronds of the abun- dant Pteris podophylla Sw. (sensu lato), and making a mat on the dusty floor for sleeping-bags. Fire-making and cooking, as well as the drying of specimens, must be done out of doors. We found Casita Alta exactly as we had left it at the end of the preceding summer, even to the sprig of mistletoe hung over the door like the sword of Damocles. Immediately after un- packing our belongings that Mr. Mónniche thoughtfully had had packed up the mountain side for us by mule-train we set about the construction of a **pressing room,"' or rather, a can- vas shelter for our press-frames. During the rainy season, at least, artificial heat is necessary for drying in the tropies. After experiments over several collecting seasons, we have found that the one-unit, pressure kerosene stoves of Swedish make are by far the hottest, safest, and most economical. It would be difficult to find a site more attractive to the botanical collector than that of Casita Alta, since it is located within easy reach not only of the deep valley of the Río Caldera PLATE 18 "e aie & AN ALPINE MEADOW NEAR THE SUMMIT OF VOLCÁN DE CHIRIQUI ANN. Мо. Вот. GARD., VOL. 26, 1929. 19 PLATE 1939 6, ә VOL. от, GARD., ANN. Mo. 19397 nibo uet aspi. ut P Ji gb г upto vn res um WOODSON & SEIBERT—FLORA OF PANAMA. III 269 headwaters, but of the higher slopes of the volcano itself. We soon found that it was a good arrangement for two of the party to go fairly far afield, leaving the third to tend the kero- sene stoves. Incidentally, the one left could collect in the imme- diate vicinity of the camp, where much of interest was to be found, including the gigantic Piper Gigas Trelease, a tree 10 m. tall with a bole 30 cm. in diameter. Another very distinct pepper of similar height but more slender bole is P. affectans Trelease, also in this immediate vicinity. А rather rare borage, Hackelia costaricensis (Brand) Johnston, was so common іп the immediate clearing around camp that it appeared to be an introduced weed. After about three weeks of collecting from Casita Alta, in- cluding a trip to the summit of the voleano, we packed up our sundries, and descended to Boquete, paying our respects, en route, to the Mónniches, through whose kindness we had had such a delightful and profitable visit. Тһе region about Bo- quete, aside from the Canal Zone, is probably the best known botanieally of Panama. Nevertheless, things were made so convenient for us at “Е Hotel Nuevo’’ that we could not forego a few days of foray, which resulted in the discovery of several interesting species. Back in the Canal Zone again, several trips were made toward Chepo, to the east, and Arraiján, just over the bound- ary to the west. A visit of several days was made to the island of Taboga, in Panama Bay. Although the island has been a favorite resort from the mainland sinee the days of Spanish domination, and has been visited probably by every botanist to eolleet on the isthmus, a number of additions were made to the flora of Panama, including the antillean Forsteronia spi- cata (Jacq.) Meyer, which grows in veritable thickets along the northern shore. Тһе last two weeks of collecting were spent by Woodson in the neighborhood of Almirante, Bocas del Toro province, for a foray at the kind invitation of Dr. Wilson Popenoe and the United Fruit Company. The Atlantie slope of Panama is more poorly known botanieally than the Pacifie, and this port had [Vor. 26 210 ANNALS OF THE MISSOURI BOTANICAL GARDEN been selected because bi-monthly sailings are made to it from Cristobal by the ships of the Fruit Company. The trip to Almirante was made with some misgivings, since the place has a rather evil reputation in the Canal Zone as a disease-infested shambles of abandonment caused by the plague of the Panama Disease of bananas. It is quite true that the disease has almost completely wiped out the traffic in bananas at Almirante, but the growing and processing of cocoa and араса is progressing under very efficient management, and will doubtless restore the importance of the port. Almirante itself is far from a shambles. The town is neatly maintained, and the people, all employees of the Fruit Com- pany and their families, are the most uniformly co-operative опе could wish. It is to Mr. John S. Kelley, the manager of the Almirante Division, and his wife, that we chiefly owe the suc- cess and pleasure of our collecting in the neighborhood of Almirante, for it was in their home that we made our head- quarters. It is largely due to their hospitality that the impedi- menta of pressing supplies were conveniently stored away for use, a safe shelter for the presses and kerosene stoves pro- vided, and arrangements made for trips into the surrounding country. From the manner that every need or wish was antici- pated, the visiting botanist would seem constantly to have been rubbing the magic lamp of Aladdin. At the various Fruit Company plantations, appropriately yet unexpectedly, trained and discerning naturalists were much in evidence. Dr. Cordes and Mr. Arnold both are enthu- siastic amateur botanists, and both have fine collections of living orchids. At Nievecito, in the valley of the Rio Sixaola, we were most fortunate to have Mr. H. J. Bartlet not only as host, but as a guide and companion in the field. Merely follow- ing Mr. Bartlet upon his daily travels about the plantation was reward enough for a visit to Panama, because of his activity, understanding, and knowledge of the native vegetation. It was almost in Mr. Bartlet’s ‘‘front yard’’ that a very unusual eueurbit was found which it has not been possible to refer satisfactorily to a genus. A most stimulating visit was made 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 211 to Mr. J. H. Permar, near Guabito, in the valley of Río Chan- guinola. We had long been anxious to meet Mr. Permar, since Dr. Popenoe had commented to me, at several times, on his understanding of tropieal natural history. Upon his planta- tion of ађаса Mr. Permar has established a small botanical garden of economie plants suitable for cultivation in the tropies of both hemispheres. Perhaps the most interesting of the trips taken out from Almirante was that arranged for us by Mr. Kelley to the Río Crieamola at the east end of the Chiriquí Lagoon. Leaving Almirante one morning at about four o'clock, we stopped at the town of Bocas del Toro to pick up Mr. H. Wedel, a local ornithologist and accomplished photographer, who was to act as guide and interpreter. Proceeding thence by the United Fruit Company's Diesel-powered yacht ‘‘Talamanca,’’ we ar- rived at the bar of the Río Cricamola shortly before noon. From the bar, we ascended the river in two long cayucas, or dug-out сапоев, piled high with every convenience which the Fruit Company could provide, including the precaution of six cages of carrier pigeons for communication to Almirante. We made our headquarters for the several days of our visit, at a ruined plantation called **Finca St. Louis,’’ not far down- stream from the Indian village known as Konkintoé. Once an elaborate establishment, the ill-starred Finca St. Louis is a rambling frame building of two stories in a most dismal state of decay. Nothing now remains of the plantings, the lowland jungle pressing close upon every side, as only such tropical second growth ean. Upon the rotting fence-posts was found good collecting of many epiphytes ordinarily growing high in trees. Amongst these were some interesting novelties and new records in Orchidaceae and Gesneriaceae. In the half- submerged borders of the river a good representation of Mar- antaceae, Zingiberaceae, and Araceae was collected. And with the aid of Martin Sparks, a young Bocatorefio who had accompanied us in a duplex réle of butler and scientific techni- cian, a fair sample was taken of all available flowering and fruiting trees. [Vor. 26 212 ANNALS OF THE MISSOURI BOTANICAL GARDEN After returning again to the comparative luxury of Bocas del Toro, we accepted the hospitality of Mr. Wedel for a col- lecting trip upon Isla de Colón, where the town of Bocas del Toro is situated. With only a short time at our disposal, scarcely a decent start could be made in the botanical explora- tion of this interesting and accessible district. But, thanks to the kindly experience of Mr. Wedel, in only a few days numer- ous additions were made to the known flora of Panama, here very similar to that of Atlantic coastal Costa Rica. There is probably no one in the vicinity of the Chiriquí Lagoon who is quite so familiar with the country and its inhabitants as Mr. Wedel. Since last spring, he has started independently collect- ing, sending his specimens to the Missouri Botanieal Garden for identification and distribution. LYCOPODIACEAE (William В. Maxon, Washington, D. С.) LYCOPODIUM ERYTHRAEUM Spring—curiqví: Loma Larga to summit, Voleán de Chiriquí, alt. са. 3000 m., July 5, 1938, Woodson, Allen & Seibert 1079. Previously known only from Ecuador, Peru, and Bolivia. It almost certainly occurs in Colombia as well. ISOETACEAE (W. R. Mazon and C. V. Morton, Washington) Івовтвв panamensis Maxon & Morton, sp. nov. Sect. Tuber- culatae. Planta aquatiea; rhizoma trilobatum grossum, ca. З em. latum; folia rigida, са. 50, са. 32 ст. longa, 2 mm. medio lata, apice acuminata, basi valde dilatata (margine hyalina ca. 8 em. longa, basi 5-6 mm. lata utroque latere), valde tri- quetra, septis transversis numerosis perspieuis, stomatibus numerosis, fasciculis fibrovascularibus periphericis validis 6; ligula deltoidea, ca. 3.5 mm. longa, 5 mm. basi lata, acuta; vel- lum nullum; sporangia magna, ambitu elliptica, ca. 13 mm. longa, 6-7 mm. lata; maerosporae albae, 350-500 и diam., valide ubique tuberculatae, tubereulis non confluentibus, mag- nis, elongatis (saepe 25 џ longis), apice rotundatis, costis com- missuralibus perspicuis; microsporae parvae, ca. 25 и diam., laeves.—PANAMÁ: pond, vicinity of Bejuco, Aug. 7, 1938. 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 273 Woodson, Allen & Seibert 1685 (U. S. Nat. Herb. no. 1,748,502, TYPE). In Dr. Pfeiffer's monograph the present species seems to be nearest Isoetes Malinverniana Cesati & De Not. of Italy. Speci- mens collected by Cesati and Malinverni and others, kindly lent by the New York Botanical Garden and the Gray Herbar- ium, show that species to differ in having the ligule lanceolate, the maerospores larger (660—900 y), and the mierospores roughened. Isoetes cubana Engelm., of Cuba and British Hon- duras (?),is a laxer and more slender plant, with maerospores bearing low rounded tubercles. 1. Gardneriana A. Br. of Bra- zil is similar in habit, but the maerospores are dark brown and bear fine tubercles. In the treatment by Т). Weber! 1. panamensis would fall in the section Amphibiae near I. Gardneriana and I. triangula Weber. The latter is represented in the U. S. National Herbar- ium by a specimen of the type collection (Ule 8000, from Río Branco, Amazonas, Brazil). It is distinguished from I. pana- mensis by the bilobed rhizome and the small sporangia (5 mm. long). No species of Isoetes has previously been known from Pan- ama, and only one species has been found in adjacent Central America, namely, 1. Storkii T. C. Palmer, of the mountains of Costa Rica. Isoetes panamensis is a lowland species growing near sea level. HYMENOPHYLLACEAE (William В. Maxon, Washington, D. C.) TRICHOMANES Амхкевнвп Hook. % Grev.—socas DEL TORO: fronds thickly **plastered" to tree trunk, Isla de Colón, alt. ca. 25-75 m., Aug. 18, 1938, Woodson, Allen Ф Seibert 1933. Pre- viously known from Costa Rica, and from Colombia to Bolivia. POLYPODIACEAE (William В. Maxon, Washington, D. C.) ПОтьгатом Ілхрвевап (Mett.) Christ.—socas DEL TORO: vi- cinity of Nievecito, alt. ca. 15 m., Aug. 8, 1938, Woodson, Allen 1U. Weber, ‘‘Zur Anatomie und Systematik der Gattung Isoetes L.,"" Hedwigia 63: 219-262. 1922. [Vor. 26 214 ANNALS OF THE MISSOURI BOTANICAL GARDEN Ф Seibert 1801. This species, newly recorded from Panama, was described from Brazil, and is reported from Mexico (рет- haps in error), Colombia, and Venezuela. At the U.S. National Herbarium we have under this cover specimens ranging from Costa Riea to Colombia and Bolivia. The Panama plant agrees with the Costa Rican specimens, but this material may not be conspecifie with the Brazilian type. As regarded at present it must be reckoned a polymorphic species. Er4APHoaLossUM DomBryanum (Fée) Moore—currigui: steep cliffs of Potrero, near summit, Voleán de Chiriquí, alt. ca. 3300 m., July 5, 1938, Woodson, Allen £ Seibert 1048. Known previously from Colombia, Venezuela, and Ecuador. STRUTHIOPTERIS LOXENSIS (HBK.) Maxon—cuiriqui: Loma Larga to summit, Voleán de Chiriquí, alt. ca. 3000 m., July 5, 1938, Woodson, Allen & Seibert 1067. Specimens in the U.S. National Herb. are from Colombia, Ecuador, Peru, and Bo- livia. OPHIOGLOSSACEAE ( R. T. Clausen, Ithaca, N. Y.) OPHIOGLOSSUM NUDICAULE L.f. var. TENERUM (Mettenius) Clausen—panaMA: wet savanna, east of Pacora, June 19, 1938, Woodson, Allen € Seibert 727. The first record of this species from Central America. CYPERACEAE (H. K. Svenson, Brooklyn, N. Y.) Carex Lemanniana Boott—cuiriqui: common on potrero, forming dense tussocks, near summit, Volcán de Chiriquí, alt. са. 3300 m., July 4-6, 1938, Woodson, Allen & Seibert 1057. Re- ported by Standley (Fl. Costa Rica 1: 96. 1937) as occurring from Costa Rica to Ecuador at altitudes above 2000 m., but apparently never before collected in Panama. CYPERUS ALBOMARGINATUS Mart. & Schrad.—canaL ZONE: near Fort Kobe road, July 22, 1938, Woodson, Allen & Seibert 1427. Not previously reported from Panama. This number is very peculiar in its light scales; all other material examined from Mexico and Central America has ferruginous scales. 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 215 RvwcHosPonA TRIFLORA Vahl—pranamA: boggy grasslands and marginal thickets between Pacora and Chepo, Aug. 1, 1938, Woodson, Allen & Seibert 1663. A widespread tropical species not reported from Central America. BROMELIACEAE (L. B. Smith, Cambridge, Mass.) TILLANDSIA PUNCTULATA Schlechtd. & Cham.—cuiriqui: vi- cinity of Casita Alta, Voleán de Chiriqui, alt. ca. 1500-2000 m., June 28-July 2, 1938, Woodson, Allen & Seibert 991. Pre- viously known from southeastern Mexico to Costa Rica, and reported from Surinam. VnrEsrA Woodsoniana L. B. Smith, spec. nov. (pl. 20), acau- lis; foliis rosulatis, ad 5 dm. longis, vaginis ellipticis, basi cas- taneis, dense punctato-lepidotis, laminis ligulatis, 3 cm. latis, apice rotundato-apiculatis, concoloribus, subtus minute dense- que lepidotis, supra glabris; scapo erecto, glabro, vaginis foli- aceis dense induto; inflorescentia simplicissima, curvata, sub- dense pauciflora, ca. 15 em. longa; bracteis florigeris imbricatis, paulo secunde versis, latissime ovatis, ad apicem versus trian- gulo-acutis, ad 45 mm. longis et 33 mm. latis, quam sepala longioribus, glabris, valde rugosis, nullo modo carinatis, basi atro-castaneis ; floribus valde secundis; pedicellis 1 cm. longis, valde incrassatis ; sepalis late ovatis, acutis, 35-40 mm. longis, subtenuibus, impresso-puncticulatis; petalis imperfecte cogni- tis, basi ligulis binis ad 1 em. longis auctis; staminibus veri- similiter inclusis.—cnuigiQví: Bajo Mona, mouth of Quebrada Chiquero, along Río Caldera, alt. са. 1500-2000 m., July 3, 1938, Woodson, Allen Ё Seibert 1029 (Herb. Missouri Bot. Garden, ТҮРЕ; Gray Herb., photograph and analytical drawings). In its combination of rugose floral bracts and secund flowers, Vriesia Woodsoniana is quite unlike any previously known species. JUNCACEAE Ілу?тл,А GIGANTEA Desv. var. vulcanica Woodson, var. nov., а var. typ. differt foliis angustioribus (0.7—0.9 cm. latis) margine longiuscule denseque ciliatis; tepalis saturate castaneis apice [Vor. 26 216 ANNALS OF THE MISSOURI BOTANICAL GARDEN vix mucronulatis.—currigut: “Е Potrero,’’ Volcán de Chiri- qui, alt. ca. 3380 m., July 4-6, 1938, Woodson, Allen & Seibert 1094 (Herb. Missouri Bot. Garden, түре). This is apparently the first record of the species from Panama. Only the forbid- ding technical difficulties of the genus prevent me from de- scribing var. vulcanica as a species, so different does it appear, especially in the foliage, from material that I have seen from Mexico and Costa Riea, and from published plates from South American plants. It forms extensive colonies on the volcanic floor of “КІ Potrero," immediately beneath the peak of the Volcán de Chiriquí. MUSACEAE Heticonia nutans Woodson, spec. nov. (Sect. Taeniostro- bus O.Ktze.). Herba valida ca. 2-metralis. Folia longe petio- lata, petioli 25-30 cm. longi subteretes longitudinaliter striati ca. 0.3 em. erassi, vagina 20 em. longa ore membranacea pur- purissata, lamina oblongo-elliptica apice abrupte acuminata basi late cordata apice obtusa usque 60 em. longa 24 em. lata superne minora utrinque viridis glabra. Inflorescentia longe pedunculata, pedunculo 20-32 ст. longo graciliusculo erecto glabro, rhachi nutanti flexuoso-curvato 15-25 em. longo ca. 0.4 em. diam. dense ferrugineo-tomentoso, bracteis 4-7 ambitu lanceolatis latiuscule eymbiformibus apice longe acuminatis basi subamplexicaulibus 6-13 em. longis 2.0-2.5 em. latis cari- natis rubidulis margine extus minute ferrugineo-hirtellis cae- terumque glabris, bracteolis ovatis acuminatis 2-4 ст. longis papyraceis nervo medio ferrugineo-hirtellis caeterumque gla- bris. Flores іп bractearum axillis ca. 4-7, pedicellis ca. 0.2 em. longis sparse pilosulis, ovario clavato са. 0.6 ст. longo apice са. 0.25 cm. crasso glabro, tepalis anguste lanceolatis acumi- natis ca. 4.7 cm. longis paulo arcuatis aurantiacis extus mar- gine pilosulis intus omnino pilosulis, staminibus 5, filamentis 9 em. longis tomentellis, antheris haud visis, staminodio vix 0.3 em. longo, stylo 5 em. longo glabro. Capsula ovoidea 1 ст. longa 0.8 cm. crassa glabra atro-violacea.—cnrmiqví: vicinity of Casita Alta, Volcán de Chiriquí, alt. 1500-2000 m., June 28- July 2, 1938, Woodson, Allen & Seibert 968 (Herb. Missouri Bot. Garden, түре). 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 977 Apparently most closely related to H. marginata, of Darién province, Panama, but differing in the cordate leaves and smaller inflorescence, as well as in technical details of the flowers. ZINGIBERACEAE Costus Lima K.Sch.—cuirigut: moist valley thickets, west of Remedios, June 24, 1938, Woodson, Allen & Seibert 786; BOCAS DEL TORO: vicinity of Nievecita, alt. 0-50 m., Aug. 8-19, 1938, Woodson, Allen & Seibert 1835. This magnificent species with dark crimson, leafy bracts, which was previously con- sidered as endemic to Costa Rica, was found in numerous lo- ealities at low elevations upon both coasts of Panama in Chiriqui and Bocas del Toro. One variation of the species from the latter province, which is distinguished well by its pale pink or flesh-colored bracts, may be described as follows: Costus Lima K.Sch. var. Wedelianus Woodson, var. nov., ab var. typ. bracteis obtusiusculis brevioribus carneisque differt. —BOCAS DEL TORO: Rio Cricamola, between Finca St. Louis and Konkintoé, alt. ca. 10-50 m., Aug. 12-16, 1938, Woodson, Allen & Seibert 1926 (Herb. Missouri Bot. Garden, түре). This variety, which may well merit specific rank, is named in honor of Mr. H. Wedel, the ornithologist of the city of Bocas del Toro, to whom we owe much aid during the trip up the Crica- mola River and elsewhere in Bocas del Toro. Совттув ARGENTEUS В. & Р.—РАМАМА : thickets and forests near Arraiján, alt. са. 15 m., July 21, 1938, Woodson, Allen & Sei- bert 1358; cHtriqui: thickets west of Remedios, June 24, 1938, Woodson, Allen € Seibert 789. Considerable confusion has surrounded the identity of this magnificent species, which is common in midsummer in the Canal Zone and occurs else- where in the Republic upon both coasts, especially the Pacific. Recorded distribution of C. argenteus has been confined to western Peru and Ecuador. All the collections of the species that I have seen have been assigned to C. villosissimus Jacq., a very different and common plant of smaller stature and cov- ered everywhere save the flower itself with a long, yellow- hirsute indument. Plate 14 in Standley's ‘‘Flora of the Panama [Vor. 26 218 ANNALS OF THE MISSOURI BOTANICAL GARDEN Canal Zone,’’ represents C. argenteus rather than C. villosis- simus. Тһе two species, occurring so commonly together, pre- sent strong evidence of hybridization. Seibert 593, collected in the vieinity of Gold Creek, near Gamboa, Canal Zone, and dis- tributed as C. villosissimus, is a striking example of the puta- tive hybrids. Recently I have had the good fortune, through the kindness of Professor Domin, of examining the type of C. hirsutus Presl (Haenke s.n. in Herb. Mus. Nat. Prag.). The specimen appears to me quite conspecific with those more correctly referred to C. villosissimus Jacq. RENEALMIA EXALTATA L.f.—socas DEL токо: Río Cricamola, between Finca St. Louis and Konkintoé, alt. ca. 10-50 m., Aug. 12-16, 1938, Woodson, Allen & Seibert 1905. It is almost in- credible that this common and widespread species of the Carib- bean and northeastern South America has not previously been reported for Panama. Neither have I seen herbarium speci- mens from the republic. It is not uncommon in the lowlands bordering the Río Cricamola, and probably is to be found else- where along the Atlantic coast. MARANTACEAE CaLATHEA quadratispica Woodson, spec. nov. Planta valida 2-3 m. alta. Folia longissime petiolata, petioli pars superior paulo compressa саПова 15-17 cm. longa glabra vel minutis- sime sparseque papillosa pars inferior ca. 75-95 cm. longa, lamina inaequilateraliter ovata basi late obtusa apice rotun- data 80-95 cm. longa 47-50 em. lata utrinque viridis inferne paulo pallidior durius herbacea margine minute puberula caeterumque glabra, vagina scariacea 25-26 cm. longa margine minute puberula. Spicae 2 quadrato-cylindricae 14-15 em. longae са. 3 em. diam., pedunculo 25-30 em. longo apice dense puberulo in vagina incluso; bracteae distichae 30-34 dense imbrieatae latissime ovatae vel suborbieulatae apice rotun- datae vel paululo retusae margine vulgo plus minusve revo- lutae ad 3 em. longae sparse minuteque pilosulae superne apicem versus densius scariaceae aureae 6-8-florae; paria 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 219 florum brevissime (ca. 0.1 em. vel minus) pedicellatorum 8-12 bracteolis scariaceis exterioribus са. 2.5 em. longis ca. 1.2 em. latis latissime oblongis valde conduplicatis apice truncatis haud profunde 2-4-lobatis interioribus multo minoribus ob- longo-lanceolatis acuminatis ; ovarium са. 0.3 ст. longum gla- brum vel minute papillatum ; sepala oblonga late obtusa 1.7- 1.8 em. longa glabra; corollae flavae tubus anguste cyatho- cylindricus 2.8-3.0 em. longus basi са. 0.07 em. diam., ostio ca. 0.125 em. diam., lobi ovato-lanceolati acuti ca. 0.8 em. longi, stamen paululo exsertum 0.3 em. longum compresse ellipsoi- deum, staminodium exterius oblique obovatum flavum 1.1 cm. longum, callosum brevius cucullatum 0.7 em. longum; capsula non visa.—BOCAS DEL TORO: swampy margins of Río Cricamola, between Finca St. Louis and Konkintoé, Aug. 12-16, 1938, Woodson, Allen & Seibert 1913 (Herb. Missouri Bot. Garden, TYPE). When first studied, this species was thought possibly to represent C. sclerobractea K.Sch., which is known to occur only in Guatemala. From the latter, however, and from all other species known to me, C. quadratispica differs quite ob- viously in the rather strongly quadrate-compressed spikes. It is not uncommon in the valley of the Rio Cricamola, where it occurs with the familiar C. lutea and C. insignis. ORCHIDACEAE (L. O. Williams, Cambridge, Mass.) PHRAGMIPEDIUM CAUDATUM (Lindl.) Rolfe, in Orch. Rev. 4: 332. 1896; Pfitzer, in Engl. Pflanzenr. IV. 50 (Heft 12): 52. 1908, in synon.—Cypripedium caudatum Lindl, Gen. & Sp. Orch. Pl. 531. 1840; Selinipedium caudatum Rchb.f., in Bon- plandia 2: 116. 1854; Paphiopedilum caudatum Pfitzer, in Engl. Bot. Jahrb. 19: 41. 1894; Paphiopedium caudatum Kerch., Orch. 454. 1894.—снівІф0ї: vicinity of Casita Alta, alt. 1500-2000 m., June 28-July 2, 1938, Woodson, Allen & Sei- bert 962. Phragmipedium caudatum has been reported from Chiriquí by Reichenbach (Beitr. Orch. Centr.-Am. 44. 1867), but no specimen was cited by him. Тһе specimen cited above would [Vor. 26 280 ANNALS OF THE MISSOURI BOTANICAL GARDEN seem to be the second collection from Panama. Тһе species is known in Costa Rica, Colombia, Ecuador, and Peru. The original spelling of the generic name was Phragmipe- dium. Pfitzer changed the spelling to Phragmopedilum, in his treatment of the group, and accredited all the combinations to Rolfe except опе.! This change of the spelling of the generic name is not permissible. HABENARIA HEPTADACTYLA Rchb.f., іп Linnaea 22: 812. 1849. —PANAMÁ: terrestrial, thickets and forests near Arraiján, alt. about 15 m., July 21, 1938, Woodson, Allen & Seibert 1406; without definite locality (Canal Zone or Panama Province), - A. M. Bouché, Jr. 7. Habenaria heptadactyla does not seem to have been re- ported from Panama previously. It is known to occur in Vene- zuela, British Guiana, and Brazil. HABENARIA PAUCIFLORA (Lindl) Rchb.f., in Bonplandia 2: 10. 1854.—Habenaria setifera Lindl., in Ann. Nat. Hist. 4: 381. 1840.—РАХАМА : boggy grasslands and marginal thickets, be- tween Pacora and Chepo, alt. about 25 m., Aug. 1, 1938, Wood- son, Allen & Seibert 1665. Previously reported from Chiriquí as H. setifera by Schwein- furth (Ann. Mo. Bot. Gard. 24: 182. 1937). This species ranges from Mexico to Argentina. Рохтнтвкул Ерніррпум Rchb.f., in Linnaea 28: 382. 1856.— CHIRIQUÍ: terrestrial, Finca Lérida to Boquete, alt. 1300-1700 m., July 8-10, 1938, Woodson, Allen € Seibert 1118. New to Panama and Central America. Not previously re- corded south of the state of Puebla in Mexico. Ponthieva Ephippium is very closely allied to P. racemosa (Walt.) Mohr, but has a lip with two small calluses at the base of the blade and is usually a smaller plant with smaller fiowers. PLEUROTHALLIS УІТТАТА Lindl., in Bot. Reg. 24: Mise. 73. 1838; Fol. Orch. Pleurothallis, 18. 1859.—Pleurothallis poly- 1 PHRAGMIPEDIUM Hartwegii (Rehb.f.) L. О. Williams, comb. nov.—Cypripe- dium Hartwegii Rchb.f., in Bot. Zeit. 10: 714. 765. 1852; Selinipediwm Hartwegii Rehb.f., in Bonplandia 2: 116. 1854; Xen. Orch. 1: 3, 70. 1.27. 1854; Phragmope- dilum Hartwegii Pfitzer, in Engl. Pflanzenr. IV. 50 (Heft 12): 48. 1903. 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 281 stachya Rich. & Gal., in Ann. Sci. Nat. ІП, 3: 16. 1845; Pleuro- thallis mandibularis Kranzl., in Vid. Medd. Naturh. Foren. 71: 169. 1920; Pleurothallis Bourgeawi Kranzl., in Ark. f. Bot. 16°: 15. 1920.—cocL#: epiphytic, between Las Margaritas and El Valle, July 15-Aug. 8, 1938, Woodson, Allen & Seibert 1282. Pleurothallis vittata is new to the flora of Panama. Pre- viously it has been known from Mexico and Honduras and was reported from Venezuela by Lindley. The record for Vene- zuela cannot be verified here, as the specimen on which the record was based (Fendler 1481) is lacking from the Fendler collection at the Gray Herbarium. MaraAxis MAJANTHEMIFOLIA Schltr. & Cham., in Linnaea 6: 59. 1831.--снінтот/і: terrestrial, vic. of Casita Alta, Volcan de Chiriquí, alt. 1500-2000 m., June 28-July 2, 1938, Woodson, Allen & Seibert 830. Malaxis Majanthemifolia is new to the flora of Panama. The species was previously recorded from Mexico, Honduras, and Guatemala. The flowers of the Panamanian collection are somewhat unusual in that the lateral sepals are adnate almost to their tips. | Maraxis Равтнохп Morren, іп Bull. Acad. Roy. Belg. 5: 485, t. 1838. снтвтоо!: terrestrial, Finca Lérida to Boquete, alt. 1300-1700 m., July 8-10, 1938, Woodson, Allen & Seibert 1172; CANAL ZONE: terrestrial, vie. of Salamanea Hydro- graphie Station, Río Pequení, alt. about 80 m., July 28-29, 1938, Woodson, Allen & Seibert 1581. Malaxis Parthonii seems not to be recorded from Panama although it is known from Mexico to Costa Rica and again in northern South America. Maraxis Woodsonii L. O. Williams, sp. nov. (pl. 21, figs. 1-2). Herba nana, terrestris. Caulis brevis, inferne bulbosus, supra medium bifoliatus. Folia subaequalia, late ovata. Inflores- centia subumbelliformis. Segmenta perianthii patentia. Sepala late lanceolata, obtusa. Petala filiformia. Labellum quadra- tum, apice trilobatum; auriculae lineari-lanceolatae, acutae. Columna minuta. Small terrestrial herbs up to about 15 cm. tall. Stems short, [Vor. 26 282 ANNALS OF THE MISSOURI BOTANICAL GARDEN swollen and pseudobulbous below, covered with the sheathing petioles of the leaves and by basal braets. Leaves two, sub- equal, broadly ovate, obtuse or acute, 1.5-5.5 em. long and 1.3- 4.5 em. broad, appearing sessile and to be borne well above the middle of the stem but actually with a long petiole which sheathes the stem, margin of the blade erenulate or obscurely serrate, several-nerved. Inflorescenee many-flowered; floral braets short, lanceolate, scarious; pedicels erect or spreading, about 1 em. long. Sepals broadly lanceolate, obtuse, obscurely 3-nerved, 2.5-4 mm. long and 1.5-2.5 mm. broad, margins strongly recurved, especially on the dorsal sepal. Petals fili- form, about 2.5-3 mm. long. Lip quadrate in outline, about 3.5-5 mm. long and 3-3.5 mm. broad; apex of the lip 3-lobed, mid-lobe small, exceeded by the lateral lobes in length, lateral lobes large, rounded, obtuse; the basal auricles linear-lanceo- late, acute, 1-2 mm. long, parallel to the axis of the lip, arising well up from the base of the lip; disk with two shallow cavities extending from the base of the column. Column short, about 1 mm. long.—cnurmiqví: terrestrial, vic. of Casita Alta, Volcán de Chiriqui, alt. about 1500-2000 m., June 28-July 2, 1938, Woodson, Allen & Seibert 831 and 832 (Herb. Ames, Cam- bridge, Mass., No. 55,715, түрк). Malaxis Woodsonii is distinguished from all other Ameri- can species by the position of the basal auricles of the lip as well as by less obvious characters. Liparts ВРАТА Lindl., in Bot. Reg. 14: t. 1125. 1828.—САМАТ, ZONE: epiphytic, vic. of the Salamanca Hydrographic Station, Rio Pequení, alt. about 80 m., July 28-29, 1938, Woodson, Allen & Seibert 1580. Although Liparis elata does not seem to have been recorded from Panama previously it ranges from Florida, the West Indies, and Mexico, south to northern South America. Ерітехоком Boothii (Lindl.) L. О. Williams, comb. nov.— Maaillaria Boothii Lindl., in Bot. Reg. 24: Mise. 52. 1838; Di- nema paleaceum Lindl, in Bot. Reg. 26: Misc. 51. 1840; Epi- dendrum auritum Lindl., in Bot. Reg. 29: Mise. 4. 1843; Ері- 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 283 dendrum Lindenianum Rich. & Gal., in Ann. Sci. Nat. III, 3: 20. 1845; Epidendrum paleaceum Rchb.f., Beitr. Orch. Centr.- Am. 80. 1860; in Saunders? Ref. Bot. 2:1. 87. 1869; Ames, Hub- bard & Schweinf., Genus Epidendrum in U. S. & Mid. Am. 140. 1936; Nidema Boothii Schltr., in Fedde Repert. Beih. 17: 43. 1922.—восав DEL Tono: epiphytic, Río Cricamola, between Finca St. Louis and Konkintoé, alt. about 10-50 m., Aug. 12-16, 1938, Woodson, Allen & Seibert 1892. Epidendrum Boothii is new to the flora of Panama, although it was known in Mexico, throughout Central America except Panama, Cuba, Venezuela and Dutch Guiana. Ames, Hubbard and Schweinfurth, in their study of Epiden- drum, did not take up Мал ағ%а Boothu, which is the oldest name for the species, because they supposed that Epidendrum Boothianum Lindl. would make a homonym of the combination Epidendrum Boothii. This, however, is not the case as Epiden- drum Boothianum is adjectival in form while Epidendrum Booth is genitive (cf. International Rules of Botanical No- menclature, ed. 1935, Art. 70, note 4). EPIDENDRUM IsoMERUM Schltr., in Fedde Repert. 2: 132. 1906.--восав DEL TORO: epiphytic, pendulous in dense clumps, Río Cricamola, between Finca St. Louis and Konkinto$, alt. about 10-50 m., Aug. 12-16, 1938, Woodson, Allen & Seibert 1886. Epidendrum isomerum does not seem to have been pre- viously reported from Panama, although there is а fragment in the Ames Herbarium collected by G. S. Miller, Jr., near Río Medio in the Canal Zone. Previously recorded from Mexico, Guatemala, Honduras, and Costa Riea. EPIpDENDRUM PRISMATOCARPUM Rchb.f., in Bot. Zeit. 10: 729. 1859.-снінтот/і: on fallen logs, Finca Lérida to Boquete, alt. about 1300-1700 m., July 8-10, 1938, Woodson, Allen & Seibert 212%. The type of Epidendrum prismatocarpum came from Chiri- quí, but there is no record in the Ames Herbarium of the plant having been re-collected in Panama. The species is not un- common in Costa Rica. [Vor. 26 284 ANNALS OF THE MISSOURI BOTANICAL GARDEN GarEANDRA Bavuzni Lindl. in Bauer, Ill. Orch. Pl. Gen. t. 8. 1832 (7); Gen. 6 Sp. Orch. Pl. 187. 1833; in Bot. Reg. 26: 1. 49. 1840; Bateman, Orch. Mex. & Guat. t. 19. 1840.—Galeandra Bateman Rolfe, in Gard. Chron. ПІ, 12: 431. 1892.--восав DEL TORO: in swamp near Almirante, at sea-level, flowered in Panama Aug. 20, 1939, (comm. Paul H. Allen to) Hugo Nash 1962. Galeandra Baueriis new to the flora of Panama. It has been recorded previously from Mexico, British Honduras, Guate- mala, Honduras, and French Guiana. Since Rolfe gave a new name to the Mexican plants іп 1892, the name seems to have been universally adopted. Rolfe dis- tinguished G. Batemani as having “а short ovoid pseudobulb, and a dull purple lip’’ and G. Bauer? as having “а slender fusi- form pseudobulb, and a pale-coloured lip." Most of the Mexi- ean and British Honduran material examined has slender pseudobulbs, but the shape seems to depend on age, the younger ones being slender, the older ones thicker. In regard to the coloration of the flowers it must be remembered that Bauer's drawings were made from a dried specimen which could have lost its color—as have most of the specimens in the Ames Herbarium. WaRREA COSTARICENSIS Schltr., in Fedde Керегі. 16: 446. 1920.—cuiriqui: terrestrial, deep shade near Potrerillos, 1939, Allen s.n.; locality lacking, alt. 3000 ft., 1938, Kieswetter 8.0. It is with some hesitation that the above plants are referred to Schlechter’s species but it is perhaps best to place them here until the species is better known. In the specimens cited the lip is oval to round and appar- ently not emarginate, while Schlechter described and drew the lip of Warrea costaricensis as oblong aad emarginate. If Schlechter’s drawings are correct, there are also differences in the stipe and the gland of the pollinia between the Panamanian plants and Schlechter’s specimens, which were from Costa Rica. 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 285 GovENIA CILIILABIA Ames & Schweinf., in Sched. Orch. 10: 80. 1930.—снтв1901 : vie. of Casita Alta, Volcán de Chiriquí, alt. about 1500-2000 m., June 28-July 2, 1938, Woodson, Allen Ф Seibert 947. Govenia cilülabia is the rarest species of the genus in Cen- tral America. The original and, until now, the only known specimen of the species was collected at Cola de Galla, Costa ica. MaxiLLARIA RINGENS Rchb.f., in Walp. Ann. 6: 523. 1863; C. Schweinf., in Bot. Mus. Leafl. Harv. Univ. 4: 91. 1937.— CHIRIQUÍ: epiphytic, Bajo Mono, mouth of Quebrada Chiquera, along Rio Caldera, alt. about 1500-2000 m., July 3, 1938, Wood- son, Allen & Seibert 1010. The collection cited above is rather unusual in the large size of the flowers, otherwise it would seem to be quite typical of the species. The sepals are from 5 to 6 cm. long, and the petals are about 4.5 em. long. Known previously from Panama; also from Guatemala, Nicaragua, and Costa Rica. The synonyms, Mazillaria Rous- seauae Schlecht. and M. pubilabia Schlecht., were based on Panamanian material. RoprIGUEZIA compacta Schltr., in Fedde Керегі. Већ. 19: 144. 1923.—Bocas DEL TORO: mcer Río Cricamola, between Finca St. Louis and Konkintoé, alt. about 10-15 m., Aug. 12-16, 1938, Woodson, Allen & Seibert 1888. New to Panama. The specimen is past flower but there is little doubt concerning the identity of the plant. Previously recorded from Costa Rica. Osmoctossum anceps Schltr., in Fedde Керегі. Већ. 19: 147. 1923.—cuiriqui: epiphytic, vie. of Casita Alta, Volcán de Chiriquí, alt. about 1500-2000 m., June 28-July 2, 1938, Wood- son, Allen & Seibert 875. Previously recorded only from Costa Rica. Орохтовіоѕѕом Овввтерп Rchb.f., in Bonplandia 3: 214. 1855; Xen. Orch. 1: 189, $. 68, I. 1856.—cutriqgui: epiphytic on dead logs in dense wet forest, Loma Larga to summit, Voleán de Chiriquí, July 4-6, 1938, Woodson, Allen & Seibert 1030. [Vor. 26 286 ANNALS OF THE MISSOURI BOTANICAL GARDEN А handsome small plant previously known only from Costa Rica. Хотуша Cordesii L. О. Williams, sp. nov. (pl. 21, figs. 3-4). Herba epiphytica, parva. Folia aequantia, lineari-lanceolata vel lanceolata, acuta vel acuminata. Pseudobulbus parvus, complanatus, unifoliatus. Inflorescentia subumbellata; brac- teae scariosae, lanceolatae, acutae vel acuminatae. Sepalum dorsale lineari-lanceolatum, acuminatum, trinervium. Sepala lateralia linearia, acuminata, uni- vel binervia. Petala sepalo dorsali similia sed angustiora, basi trinervia. Labellum un- guiculatum; unguis medio biaurieulatus; lamina hastata, acuminata ; lobi laterales reeurvi, serrulati. Columna generis. А small epiphytie herb. Leaves equitant, laterally flattened, linear-lanceolate to lanceolate, acute or acuminate, sessile, 4— 6 em. long, 3-5 mm. broad (laterally). Pseudobulbs small, com- planate, inclosed in the bases of leaves, unifoliolate, 1-1.5 em. long. Inflorescence a subumbellate raceme, simple or branched; scape from the base of a pseudobulb, slender, about 4-6 em. long, with several infundibuliform bracts; bracts of the inflorescence searious, lanceolate, acute or acuminate, about 1.5-2 mm. long, spreading. Pedicels filiform, spreading, with the ovary about 6 mm. long. Dorsal sepal linear-lanceo- late, acuminate, 3-nerved, about 10 mm. long and 1.5 mm. broad. Lateral sepals linear, acuminate, slightly oblique, 1-2- nerved, about 12-13 mm. long and 1 mm. broad. Petals similar to the dorsal sepal but slightly narrower, 3-nerved at the base, l-nerved above. Lip arising at the base of the column but free from it, long-unguiculate, the claw about 4 mm. long, thickened and biauriculate at a point half way between the base of the lip and the lateral lobes, the thickening papillose- pubescent on the anterior side; blade of the lip hastate, acumi- nate, about 4 mm. long and 2 mm. broad, the lateral lobes re- curved, serrulate, the apex strongly acuminate. Column slen- der, about З mm. long, characteristic of the genus.—Bocas DEL TORO: epiphytie, Mosquito Hill, Aug. 12-16, 1938, (comm. by Dr. H. Cordes to) Woodson, Allen & Seibert 1932 (Herb. Mis- souri Bot. Garden, түре). 1939] WOODSON & SEIBERT—FLORA OF PANAMA. ІП 287 Notylia Cordesii is allied to several of the Central American species of the genus, among them N. bicolor Lindl., N. linearis А. & S, М. ramonensis Schltr., and №. Wullschlaegeliana Rchb.f. It is most closely allied to the last of these, №. Wull- schlaegeliana, from which it may be distinguished as a larger plant with distinetly larger leaves and flowers; by having the lip entirely free from the column; by having the auricles near the middle of the claw instead of at the base. It is a pleasure to name this fine little orchid for Dr. Cordes, who has shown much interest in the flora of Panama. TELIPOGON AMPLIFLORUS C. Schweinf., in Bot. Mus. Leaf. Harv. Univ. 6: 34. 1938.—cnriniQví: epiphyte, vic. of Casita Alta, Voleán de Chiriqui, alt. about 1500-2000 m., June 28- July 2, 1938, Woodson, Allen Ё Seibert 961. Telipogon ampliflorus, which was recently described from Costa Rica, is new to the flora of Panama. The flowers of the present specimens are somewhat smaller than those described by Sehweinfurth. ROSACEAE ( Alchemilla by L. M. Perry, Jamaica Plain, Mass.) ALCHEMILLA PECTINATA HBK.—currigut: vicinity of Casita Alta, Voleán de Chiriquí, alt. 1500-2000 m., common in clear- ings, June 30, 1938, Woodson, Allen & Seibert 892; Loma Larga to summit, Voleán de Chiriquí, alt. 2500—3380 m., July 5, 1938, Woodson, Allen & Seibert 1042. Known to extend from Mexieo to Colombia and Bolivia, but previously unknown from Panama. No. 1042 is a typieal specimen; 892 is a more stoloniferous and smallish specimen, but apparently belongs to this species. ALCHEMILLA APHANOIDES L.f. var. SUBALPESTRIS (Rose) Perry—curiqví: Loma Larga to summit, Volcán de Chiriquí, alt. 2500-3380 m., July 5, 1938, Woodson, Allen & Seibert 1041. Originally described from Mexico. I have not seen previously this plant from farther south than Costa Rica. Reported by Standley (Fl. Costa Riea 2: 477. 1937) as extending to Bo- livia. [Vor. 26 288 ANNALS OF THE MISSOURI BOTANICAL GARDEN HxsPEROMELEs chiriquensis Woodson, spec. nov. Arbuscula dense ramosa 1.5-3.0 dm. alta; ramis sat crassis subfastigia- tis; ramulis juventate dense minuteque fulvo-hispidulis mox glabratis haud spinescentibus, internodiis 0.1-0.4 ст. longis; foliis plerumque obovato-suborbieularibus apice rotundatis vel paulo retusis rare subacutis basi late euneatis 0.3-2.0 em. longis 0.2-1.9 ст. latis margine inconspicue depresso-serrula- tis coriaceis supra paulo illustris nervo medio dense minute- que fulvo-hispidulis subtus pallidioribus opacis nervo medio sparse hispidulis caeterumque glabris; petiolo 0.2 em. longo fulvo-hispidulo; inflorescentiis corymbosis densis plurifloris ; bracteis subfoliaceis lanceolatis 0.4-0.8 em. longis; pedicellis subnullis ; eupulis late conicis 0.3 em. longis 0.35 em. latis extus fulvo-hispidulis intus dense villosulis; sepalis triangulo-seto- sis 0.35 em. longis ut in cupula vestitis; petalis obovato-oblon- gis 0.5 em. longis 0.4 cm. latis basi unguiculatis pallide roseis; staminibus 20, filamentis 0.15-0.3 em. longis, antheris 0.07 em. longis; pistillis 0.5 em. longis basi villosulis; fructu ignoto.— CHIRIQUÍ: Loma Larga to summit, Volcán de Chiriquí, alt. ca. 3300 m., July 4-6, 1938, Woodson, Allen & Seibert 1078 (Herb. Missouri Bot. Garden, түре). This handsome dwarf tree was found almost literally cov- ered with its pale pink flowers, not far below the summit of the volcano. H. obovata (Pittier) Standl., of the neighboring peaks of Costa Riea, is distinguished from it by its white, smaller petals, and spinescent twigs. Тһе extremely dwarf stature and very erowded foliage, probably induced by the high altitude, are also distinctive, as well as the depressed ser- rulation of the leaves. POLYGALACEAE (S. F. Blake, Washington) Моммтмд xaLAPENSIS HBK.—cnirigvt: vicinity of Casita Alta, Voleán de Chiriquí, alt. 1500-2000 m., June 28-July 2, 1938, Woodson, Allen € Seibert 802. Apparently new to Pan- ama; previously known from Vera Cruz to Nicaragua and Costa Rica. 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 289 EUPHORBIACEAE (P. C. Standley, Chicago) Croton Allenii Standl., sp. nov. Arbuscula 4-metralis ra- mosa, ramis gracilibus teretibus ochraceis sparse pilis stellatis sessilibus pauciradiatis pilosis, sat dense foliatis, internodiis brevibus vel elongatis; stipulae filiformi-subulatae 1.5-2 mm. longae apice glanduliferae deciduae; folia inter minora longi- petiolata herbacea, petiolo gracili 2-3.5 em. longo sparse stel- lato-piloso; lamina ovata vel oblongo-ovata 5-8 cm. longa 2.5- 4.5 em. lata acuta vel subabrupte breviter acuminata, basi late rotundata atque breviter cordata, arcte crenato-serrulata, utrinque viridis, sparsissime praesertim ad nervos stellato- pilosa, e basi 5-nervia, nervo medio supra basin utroque latere nervos са. 4 emittente ; flores monoeci racemosi, racemis termi- nalibus breviter pedunculatis 4-7 cm. longis laxe remotifloris, rhachi sat dense stellato-pilosa, pedicellis 1-3 mm. longis; flores fertiles pauci vulgo 1-2, interdum usque 6, sepalis 5 in statu fructifero 5-6 mm. longis subaequalibus lanceolato- oblongis acutis remote serratis dense stellato-pilosis erectis, petalis nullis; styli bis dichotome divisi glabri; flores masculi numerosi cito decidui in alabastro globosi atque 2.5 mm. diam., sparse stellato-pilosi; stamina ca. 10, filamentis glabris; сар- sula vix matura 5 mm. longa ubique dense pilis parvis patenti- bus stellato-pilosa.—cocrÉ: vicinity of Antón, Aug. 8, 1938, Woodson, Allen Ё Seibert 1711 (Herb. Field Mus., түре; dupli- cate in Herb. Missouri Bot. Garden). A notable addition to the rather few species of Croton known from Panama, distinctive in appearance because of its rather small and bright green leaves, which at first sight appear to be glabrous. The hairs of the pubescence vary considerably in form, but many of them are distinguished by having short basal rays and very long and soft central ones. PLUKENETIA VOLUBILIS L.—Los santos: thickets between Los Santos and Guararé, July 11, 1938, Woodson, Allen % Seibert 1201. Apparently known from Central Ameriea only by this specimen. It is recorded or represented also from Dominica, [Vor. 26 290 ANNALS OF THE MISSOURI BOTANICAL GARDEN Colombia, Peru, and Bolivia. At least one other species of the genus occurs in northern Central America. DILLENIACEAE (P. C. Standley, Chicago) SaAvRAUIA Seibertii Standley, sp. nov. Arbor, ramulis cras- siusculis fere glabris sed sparsissime atque fere minute ad- presso-furfuraceis; folia petiolata crassiuscula atque in sicco rigidula, petiolo 1.5-3.5 em. longo sparse adpresso-furfuraceo ; lamina oblongo-lanceolata 15-20 ст. longa 4.5-5.5 em. lata acuminata, basin acutam versus paullo angustata, in toto mar- gine arcte serrata, supra sublucida glaberrima, subtus ad ner- vos sparsissime adpresso-furfuracea, costa erassiuscula ele- vata, nervis lateralibus utroque latere ca. 15 angulo semirecto vel paullo latiore adscendentibus prominentibus teneris; pani- culae axillares longipedunculatae folia aequantes vel paullo longiores, pedunculo usque 15 em. longo minute sparse tomen- tello atque sparse adpresso-furfuraceo, panieulis amplis sub- laxe multifloris ca. 12 em. longis atque aequilatis, ramis dense tomentellis et sparse breviter furfuraceis, bracteis conspicuis interdum foliaceis angustis, pedicellis gracilibus dense tomen- tellis usque 15 mm. longis; sepala rotundato-ovata vel late el- liptiea са. 8 mm. longa apice obtusa vel rotundata, utrinque densissime minute tomentella; petala alba glabra rotundato- elliptica vel ovalia ca. 14 mm. longa—cuirigui: Bajo Mono, mouth of Quebrada Chiquero, along Río Caldera, alt. 1500- 2000 m., ‘‘common along Río Caldera," July 3, 1938, Woodson, Allen & Seibert 1020 (Herb. Field Mus., түре; duplicate in Herb. Missouri Bot. Garden). The practically glabrous, rather coarsely and regularly ser- rate leaves of this plant isolate it among the various Panama species of Saurauia. It is not closely similar to any of the rather numerous species occurring in Costa Rica. TILIACEAE ТАЈЕНЕА CANDIDA (Moc. & Sessé) Mart.—cocrfí: llanos be- tween Aguadulce and Antón, alt. ca. 15-50 m., July 12, 1938, Woodson, Allen & Seibert 1203. A handsome tree 10-15 m. 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 291 tall, bearing showy, white flowers. Not infrequent in the local- ity visited, but apparently not previously reported from Pan- ama. BUXACEAE (C. L. Lundell, Ann Arbor, Mich.) BUXUS сітвіғогла Spreng.—caANAL ZONE: vicinity of Sala- manca Hydrographie Station, Río Pequení, alt. ca. 80 m., July 98-99, 1938, Woodson, Allen & Seibert 1563. This interesting shrub has not been known previously to occur in Central America, having been collected or reported only in Cuba, Puerto Rico, and Venezuela. CELASTRACEAE (C. L. Lundell, Ann Arbor, Mich.) Млутемоз Woodsoni Lundell, sp. nov. (pl. 22). Arbor З m. alta. Ramuli verticillati, breves et crassiusculi, striati, glabri. Folia glabra, coriacea, obovata, oblanceolata, oblanceolato- oblonga vel elliptica, 4-8 em. longa, 1.8-4.1 cm. lata, vel inter- dum minora, apice acuta, obtusa vel rotundata, basi late cu- neata, revoluta, supra mediam serrulata, venis utrinque 6 vel 7, reticulatis ; petiolis 3-5 mm. longis. Flores fasciculati. Pedi- celli usque ad 5 mm. longi, glabri. Calyx quinquefidus, lobis laciniatis, late ovatis vel suborbicularibus, 1.2-1.8 mm. longis, glabris. Petala vinacea, late ovata vel suborbicularia, usque ad 2.5 mm. longa, erosa. Stamina 5. Ovarium 3-loculare, ovu- lis in loculis solitariis. Pedicelli fructiferi 3.5-6 mm. longi. Capsula late obovoidea, 6-7 mm. longa. Semina 1 vel 3, aril- lata, obovoidea, ca. 4.5 mm. longa. A tree 3 m. high; branchlets verticillate, rather short and stout, striate and angled, glabrous; buds covered with rufous- laciniate scales. Leaves glabrous, subverticillate at apex of branchlets, alternate otherwise. Stipules ligulate, up to 2.5 mm. long, maroon, long-laciniate. Petioles stout, 3 to 5 mm. long, shallowly grooved above. Leaf blades coriaceous to rig- idly coriaceous, obovate, oblanceolate, oblanceolate-oblong or elliptic, usually 4 to 8 em. long, 1.8 to 4.1 cm. wide, sometimes smaller, apex acute to rounded, base broadly cuneate, margin slightly revolute, conspicuously serrulate above the middle, [Vor. 26 292 ANNALS OF THE MISSOURI BOTANICAL GARDEN the serratures rounded and apiculate with short red inflexed teeth, costa prominent and rather thick beneath at base, slen- der toward apex, slightly elevated above, main lateral veins 6 or 7 on each side, prominulous beneath, plane or slightly im- pressed above, veinlets reticulate and prominulous beneath. Inflorescence usually at leafless nodes, reduced to a fascicle, the braeteoles of the reduced inflorescence persistent at base of pedicels, maroon, lacinate, forming a compact protuber- ance. Pedicels up to 5 mm. long, glabrous. Calyx deeply 5- lobed, the lobes red, laciniate, broadly ovate or suborbicular, 1.2 to 1.8 mm. long including fringe, glabrous. Petals vina- ceous, broadly ovate or suborbicular, up to 2.5 mm. long, mar- gin erose and colorless. Stamens 5. Ovary 3-celled, with 1 erect ovule in each cell. Fruiting pedicels 3.5 to 6 mm. long, jointed near base. Capsules broadly obovoid, 6 to 7 mm. long, 3-celled, 1- to 3-seeded. Seed arillate, obovoid, about 4.5 mm. long; endosperm copious; cotyledons 2.7 mm. long; radicle stout, terete, about 1 mm. long.—currievi: Loma Larga to summit, Volcán de Chiriqui, alt. 2500-3380 m., July 4-6, 1938, Woodson, Allen € Seibert 1065 (Herb. Univ. Michigan, түре in flower) ; same locality, Woodson, Allen ё Seibert 1088 (Herb. Univ. Michigan, СОТУРЕ, in fruit). M. Woodsom approaches M. verticillata (В. & P.) DC., a species of Peru with varieties in Ecuador and Colombia. The Panama tree may be distinguished by its conspicuously serru- late leaves, fascicled flowers, much larger maroon calyx-lobes, and vinaceous petals. Тһе laciniate margin of the stipules, bracts, and calyx-lobes is a noteworthy characteristic shared apparently by M. verticillata. The flowers appear to be dioe- cious, but from the material available I have not been able to determine this point definitely. MYRSINACEAE (C. L. Lundell, Ann Arbor, Mich.) Раватневів Seibertii Lundell, sp. nov. Arbor 4-6 m. alta. Ramuli erassiusculi, minute et parce adpresse rufo-lepidoti. Folia anguste oblonga vel oblongo-elliptica, 8.5-19 em. longa, 2.2-4.6 em. lata, apice basique acuminata, margine subrepanda 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 293 vel integra, membranacea, supra glabra, subtus parce et min- ute lepidota, nervis patentibus, fere 18-jugis, prominulis, punc- tulis multis (pleris breviter lineiformibus) auctis; petiolis 1.5- 2.5 em. longis. Inflorescentiae axillares, multiflorae, panicu- latae, thyrsoideae, 8-9 em. longae, parce lepidotae vel gla- brae, pedicellis usque ad 6.5 mm. longis, quam bracteis multo longioribus ; flores ante anthesin ca. 5 mm. longi, minute rufo- puberuli; sepala basi coalita, anguste triangularia, ea. 0.9 mm. longa, punctata ; petala intus tomentosa, anguste lanceolato-at- tenuata, 5 mm. longa, basi coalita, punctata ; stamina 3-3.2 mm. longa, antheris apiculatis, 1.7–2 mm. longis, dorso parce (1-4) atro-punetulatis, filamentis glabris, supra basin affixis; ova- rium ad apicem minute rufo-tomentellum ; stylus basi breviter pilosus. A tree 4 to 6 m. high. Branchlets rather thick, at first mi- nutely appressed rufous-lepidote. Leaves with petioles 1.5 to 2.5 em. long, narrowly oblong or oblong-elliptie, 8.5 to 19 em. long, 2.2 to 4.6 cm. wide, apex and base acuminate, margin somewhat repand, nearly entire, membranaceous, glabrous above, sparsely and minutely lepidote below, main lateral veins usually 18 on each side, nearly horizontal, prominulous on under-surface, picta numerous, mostly short-linear. In- florescence axillary, many-flowered, paniculate, thyrsoid, 8 to 9 em. long, sparsely lepidote or glabrous, pedicels up to 6.5 mm. long, much exceeding bracteoles; flowers before anthesis about 5 mm. long, finely rufous-puberulent; sepals united at base, narrowly triangular, about 0.9 mm. long, punctate ; petals tomentose within, narrowly lanceolate-attenuate, 5 mm. long, united at base, linear-punctate; stamens 3 to 3.2 mm. long, anthers apiculate, 1.7 to 2 mm. long, dorsally few (1—4), black- punetate, filaments glabrous, subequaling anthers, attached slightly above base of petals; ovary rufous-tomentellous at apex, base of style short-pilose.—ocnrRIQUÍ : valley of the upper Río Chiriquí Viejo, alt. 1300-1900 m., July 27, 1937, Peggy Ф Gene White 27 (Herb. Univ. Michigan, ТУРЕ). Another collection, Woodson, Allen & Seibert 798, from vicinity of Casita Alta, Volcán de Chiriqui, Province of Chiri- [Vor. 26 294. ANNALS OF THE MISSOURI BOTANICAL GARDEN quí, Panama, June 28-July 2, 1938, at alt. of 1500-2000 m., is referable here, but differs in having smaller narrowly elliptic leaves. These collectors describe the fruits as ‘‘purple-black, depressed spherically, 1.2 ст.’ in diam. The flowers are re- ported to be pale pink or pink with sweet odor. P. Seibertw is closely related to P. melanosticta (Schlechtd.) Hemsl. a species of Mexico and northern Central America, from which it may be differentiated by the entire or slightly repand, narrower, very thin, predominantly oblong leaves, and the paucity of pubescence throughout. The other related species, P. macrophylla Rusby of Bolivia, has much smaller anthers shorter than the filaments, as well as other marked differences. VITACEAE Cissus вкова L. C. Rich.—coocr£: thickets between Las Mar- garitas and Е] Valle, Aug. 8, 1938, Woodson, Allen € Seibert 1763. C. erosa is abundant in the Antilles, and has been col- lected several times in British Guiana, but this is apparently its first record in Central America. It was seen but once in the vicinity where the collection was made. GUTTIFERAE (P. C. Standley, Chicago) Hypericum Woodsonii Standley, sp. nov. Herba perennis dense caespitosa omnino glabra, caulibus numerosis 3-8 em. longis suberectis, saepe plus minusve intertextis angulatis dense foliatis; folia parva internodiis multo longiora sessilia oblonga vel oblanceolato-oblonga obtusa vel subacuta ple- rumque 3-8 mm. longa, basin versus paullo cuneato-angustata dense punctata, marginibus saepe plus minusve revolutis ; flores terminales solitarii breviter peduneulati; sepala viridia 4—5 mm. longa tenuiter nervata anguste oblonga, apice apiculato- aeutata; petala lutea sepalis aequilonga; styli 3 егесі 1 mm. longi et ultra; capsula ovoideo-oblonga 4 mm. longa apice in stylos sensim attenuata 1-locularis; semina numerosa oblonga ochracea 0.6 mm. longa.—cniRiQUÍ: forming mats on potrero, Loma Larga to summit, Volcán de Chiriquí, alt. 2500-3380 m., July 4-6, 1938, Woodson, Allen & Seibert 1040 (Herb. Field 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 295 Mus., түре; duplicate in Herb. Missouri Bot. Garden). Pros- trate in potrero, Potrero Muleto, Volcán de Chiriquí, 3120 m., July 19, 1938, Mrs. M. E. Davidson 1048 (Herb. Field Mus.). From all other species of Hypericum known from southern Central America this is conspicuously different in its low, de- pressed habit, the plant being perennial and forming dense, interlaced mats. MYRTACEAE ( P. C. Standley, Chicago) Kvueenia salamancana Standley, sp. nov. Arbor 6-metralis, ramulis crassiusculis rigidis teretibus, novellis dense pilis brevibus rigidulis patentibus pilosis, internodiis brevibus; folia mediocria breviter petiolata subcoriacea, petiolo crasso 5-7 mm. longo dense breviter piloso; lamina oblonga vel ovali- oblonga 7-9 em. longa 2.5—4 em. lata, apice rotundata atque subito caudato-acuminata, acumine са. 1 em. longo angusto at- tenuato, basi anguste rotundata, supra subopaca, ad costam subimpressam minute pilosula, aliter glabra, nervis venisque obsoletis, subtus fere concolor, ad costam prope basin laminae pilosa, aliter glabra, costa gracili elevata, nervis lateralibus utroque latere са. 12 sed obscuris, venis omnino occultis ; flores ut videtur e ramis defoliatis nascentes solitarii(?) sessiles vel brevissime pedicellati, perfecti non visi.—cANAL ZONE: vicinity of Salamanea Hydrographie Station, Río Pequení, alt. 80 m., July 28-29, 1938, Woodson, Allen & Seibert 1570 (Herb. Field Mus., түре; duplicate in Herb. Missouri Bot. Garden). In leaf characters the species is unlike any other known from the region of the Isthmus, the nervation, except for the costa, being obscure or obsolete. The form of the inflorescence, although its structure is not well established, likewise appears to be quite distinctive. MELASTOMACEAE (H. A. Gleason, New York) CENTRONIA PHLOMOIDES Ттіапа-снінішті: vicinity of Ca- sita Alta, Voleán de Chiriquí, alt. са. 1500-2000 m., June 28- July 2, 1938, Woodson, Allen & Seibert 842. Previously known from Costa Rica. [Vor. 26 296 ANNALS OF THE MISSOURI BOTANICAL GARDEN MicowiA тлмреми Naud.—cuirigui: Finca Lérida to Bo- quete, alt. са. 1300-1700 m., July 8-10, 1938, Woodson, Allen $ Seibert 1143. Previously known from Costa Rica апа Vene- zuela. ВгАКЕА Woodsoni Gleason, sp. nov. (Sect. Pyxidanthus). Arbuseula 5-7 m. alta. Rami irregulariter 4-angulati, inter- nodiis cirea 10 mm. longis paulo inerassatis, superne fur- furaceo-hispidi, pilis curvatis crasse subulatis fere 1 mm. longis. Petioli erassi, 12-25 mm. longi, sieut rami sparse hispidi. Laminae chartaceae obovato-oblongae, usque 11 em. longae 7 em. latae, apice subrotundatae ad apiculum triangu- larem brevem, integrae, basi late cuneatae, vix 3-pli-nerviae, supra glabrae arctissime brunneo-punetulatae, subtus hine inde brevissime hispidulae, praecipue ad venas. Flores soli- tarii ex axillis superioribus, pedicello 6 em. longo, hispidulo, glabrescenti. Bracteae per paria connatae, pari exteriori 12 mm. longo primo hispidulo mox glabrescenti, margine vix 2- lobato; bracteae interiores quam exteriores 3 mm. longiores, glabrae, margine integro. Calyx quam bracteae interiores 7 mm. longior, glaber, lobis 6, semicircularibus, paulo retusis et tuberculato-apiculatis. Petala anguste triangulari-obovata, alba, 4 em. longa. Antherae semi-ovatae 7 mm. longae. Stylus gracilis, ad stigma punctiforme angustatus.—cniniQvÍ: vicin- ity of Casita Alta, Voleán de Chiriquí, alt. 1500-2000 m., July 1, 1938, Woodson, Allen & Seibert 951 (Britton Herb., New York Bot. Garden, түре). It is at once distinguished from other Panama species by its totally connate bracts. The hairs of the stem, peduncles, and bracts are very easily detached. LECYTHIDACEAE GUSTAVIA BRACHYCARPA Pittier, Contr. U. S. Nat. Herb. 26: 3. 1927.—сн1в199!: swampy forests, west of Remedios, June 24, 1938, Woodson, Allen & Seibert 787. As far as we are aware, this is the first record of this peculiar specimen since the col- lection of the type by Pittier in 1911. Тһе specimens of Pittier, from near San Felix, in the same general vicinity of our trees, were in fruit only. Ours are in full flower and young fruit. In bloom, the trees of G. brachycarpa are by far the most showy 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 297 of the low forests of the country-side. The petals are pure white, 6, broadly obovate-oblong, and somewhat unequal, 4.5- 5.0 em. long, 2.2-2.5 em. broad, broadly rounded, essentially glabrous within, but very densely and minutely puberulent- papillate without. The stamens are exceedingly numerous, forming a regular, involuted cup 1.5 em. deep; the anthers are connivent, oblongoid, 0.2 em. long, and dehisce apically. The handsome flowers are borne singly or in pairs, and are slightly fragrant. Pittier’s description of the leaves, fruits, and branches is accurate, and corresponds very closely to our specimens. VACCINIACEAE (W. Н. Camp, New York) ComarostTaPHYLis chiriquensis Camp, sp. nov. Frutex 1-3 m., ramis pubescentibus; folia rectangulo-ovata, petiolo 5-8 mm. longo, basi cuneata vel acuta, apice acuta, subcoriacea, 2-6 em. longa, 1.0-1.5 cm. lata, supra glabra, subtus in foliis adultis dense ferrugineo- vel griseo-lanata, margine obscure undulata vel integerrima, revoluta; inflorescentia terminalis, panicu- lata, ubique obseure albido-puberula et plus minusve fer- rugineo-pilosa, pilis glandulosis; pedicelli 2-3 mm. longi; braetea subacuminata; calyx 5-lobus, lobis ovato-acuminatis eire. 1.5 mm. longis, puberulis et sparse glandulosis; corolla globoso-urceolata, eire. 5 mm. longa, alba, extra obscure fari- пасеа vel puberula, intra puberula, apice manifeste contracta, breviter 5-lobata, lobis puberulis ; stamina 10, filamentis basin versus dilatatis, dense pubescentibus, circ. 2 mm. longis, an- theris cire. 1.5 mm. longis, bieornutis; ovarium elongato- globosum, pubescens.—cuirigui: Loma Larga to summit, Vol- cán de Chiriquí, alt. са. 2500-3380 m., July 4-6, 1938, Woodson, Allen £ Seibert 1033 (Britton Herb., New York Bot. Garden, TYPE). This species, although closely related to C. arbutoides Lindl., may be distinguished from it by the greater number of con- spicuous gland-hairs on the rachis and pedicels, these often being 1 mm. long, and the absence of the rusty-brown, woolly tomentum on these same structures—a characteristic feature [Vor. 26 298 ANNALS OF THE MISSOURI BOTANICAL GARDEN of C. arbutoides. In this last, all the inflorescence and often the floral structures are so covered with this tomentum that their surfaces are invisible, whereas in C. chiriquensis this is not the ease. An additional interesting feature of this new вресіев is the presence on the lower surface of the leaf of scat- tered gland-hairs on and near the midvein as well as on the petioles. Minute fruiting bodies of some fungus, similar in ap- pearance to these glands, but easily recognizable as such, are also present on various organs of the type. GENTIANACEAE (F. P. Jonker, Utrecht; Halenia by C. K. Allen, Jamaica Plain, Mass.) LISIANTHUS CHELONOIDES L.f.—cuirieui: Finca Lerida to Boquete, alt. са. 1300-1700 m., July 8-10, 1938, Woodson, Allen d Seibert 1111. Previously recorded from Peru, Brazil, the Guianas, and the West Indies. SCHULTESIA BRACHYPTERA Cham. forma HETEROPHYLLA (Miq.) Jonk.—panamMA: boggy grasslands and marginal thickets, be- tween Pacora and Chepo, alt. ca. 25 m., Aug. 1, 1938, Woodson, Allen ё Seibert 1647. Previously known from Brazil, Vene- zuela, the Guianas, and Mexico. Нлгемтл Woodsoniana C. К. Allen, spec. nov. Herba per- ennis (7), саше basi ramoso procumbente; ramulis floriferis pluribus erectis usque ad 7 dm. altis ; ramulis sterilibus foliosis quam ramulis floriferis circiter № brevioribus (+ 3 dm. altis) ; internodiis inferioribus brevibus (1.5-3 em.) superioribus longioribus (4—6.5 cm.); foliis sessilibus lineari-lanceolatis acuminatis leviter 3-nerviis, nervo medio prominente, usque ad 6 em. longis et 0.7 em. latis; inflorescentia terminalis axil- larisve cymosa laxa pauciflora; calyce usque ad 1 em. longo et ad ca. 34 corollae longitudinem aequante ; lobis 3-nerviis lance- olatis acuminatis ; corollae lobis ovalibus acutis leviter erosis; calcaribus usque ad 14 corollae longitudinem aequantibus hori- zontalibus ad leviter ascendentibus ; staminibus 0.5 em. longis; capsula late lanceolata usque ad 1.7 em. Јопео.—снтв1901 : Volcán de Chiriquí, ca. 2500-3380 m., Loma Larga to summit, July 4-6, 1938, Woodson, Allen & Seibert 1052 (Herb. Missouri Bot. Garden, түре). 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 299 The above species is distinctive because of the much- branched stem, somewhat procumbent at the base, the short leafy sterile shoots arising from the main stem, and the tall spreading, loosely flowered inflorescence, the pedicels of which are often pendulous. The species, the sole representative of the genus in Panama thus far found, is most closely related to Halenia rhyacophila Allen from Costa Rica. APOCYNACEAE RavwoLFIA HIRSUTA Jacq. var. glabra (Muell.-Arg.) Woods. comb. nov. (В. canescens L. var. ò glabra Muell.-Arg. Linnaea 30: 394. 1860).—РАХАМА: Isla Taboga, thickets near sea- level, July 23-24, 1938, Woodson, Allen & Seibert 1530. FonsTERONIA spicata (Jacq.) G. Е. W. Меуег—РАМАМА: Isla Taboga, abundant, in thickets along rocky shore, July 23-24, 1938, Woodson, Allen & Seibert 1551. This species is of inter- est since it is predominantly a Caribbean element found at intervals upon the continent from southern Mexico to northern Colombia, and in Cuba. Upon the Pacific coast it has been re- ported only from Salvador and Costa Rica. This is the first record of the species from Panama. STEMMADENIA ОВОУАТА (Н. & A.) K.Sch. var. morus (Benth.) Woods.—tos santos: between Los Santos and Guararé, July 11, 1938, Woodson, Allen & Seibert 1200; vicinity of Las Tablas, alt. 15 m., Sept. 12, 1938, Allen 812. Previously re- corded from southern Mexico to Costa Rica, where it is rela- tively limited in distribution; also very local in western Ecuador. Рвквтохтл remediorum Woodson, spec. nov. Frutex volu- bilis, ramis ramulisque crassiusculis ferrugineo-hirtis. Folia obovato-elliptiea apice breviter acuminata basi obtuse cune- ata 15-18 em. longa 9-11 em. lata membranacea opaea supra subtusque ferrugineo-pilosula, petiolis 1.5 cm. longis, ap- pendicibus stipulaceis intrapetiolaribus peetinatis са. 0.25 ст. longis. Inflorescentia lateralis simplex pluriflora corymbi- formis folia са. № aequans, pedicellis ca. 1 ст. longis fer- rugineo-hirtellis, bracteis foliaceis oblongo-lanceolatis acumi- natis 1.0-1.5 ста. longis foliaceis ferrugineo-puberulis. Calycis [Vor. 26 300 ANNALS OF THE MISSOURI BOTANICAL GARDEN lobi oblongo-lanceolati acuminati 1.7-1.8 cm. longi foliacei dense ferrugineo-hirtelli, squamellis profunde pectinatis sub- eallosis ca. 0.2 em. longis appendicibus stipulaceis similibus. Corollae luteae extus dense ferrugineo-velutinae tubus sub- infundibuliformis in alabastrum submaturum 2 em. longus basi ea. 0.15 em. diam., faucibus ea. 0.35 em. diam. ; lobi obovato- dolabriformes acuminati 1.7 em. longi. Anthera 0.7 em. longa glabra арісе paululo exserta. Stigma fusiforme 0.3 em. longum; ovarium ovoideum са. 0.15 ст. altum glabrum; nec- taria 9 carnosa basi concrescentia ovarium aequantia. Fol- Пеш ignoti—cuirigut: thicket, between Río Chiriquí and Remedios, alt. са. 15-50 m., July 11, 1938, Woodson, Allen Ф Seibert 1180 (Herb. Missouri Bot. Garden, түре). When this species was collected, it was mistaken for P. isthmica Woods., an endemic of Costa Rica. Тһе leaves of P. remediorum are quite distinct, however, by reason of their cuneate base, and the conspicuous, pectinate calycine squamel- lae are quite unlike those of any species with which I am familiar. FrERNALDIA speciosissima Woodson, spec. nov. Frutex volu- bilis alte scandens, пес foliis пес calycibus песдпе ovariis visis; corollae speciosissimae albidae extus omnino glaberrimae tubo proprio 2.5-2.8 em. longo basi ca. 0.25 em. diam. strieto haud gibboso, faucibus tubulosis 2.6-2.8 em. longis intus dense arach- noideo-villosis, ostio ca. 0.6 em. diam., lobis oblique obovatis ob- tusis 2.8—3.0 em. longis patulis пон лан glaberrimis ; antheris anguste lanceolato-sagittatis basi obtuse auriculatis 1 em. longis glaberrimis; stigmate fusiformi basi minute digitato- appendiculato 0.3 em. longo.—curriqut: thickets, between Rio Chiriqui and Remedios, alt. 15-50 m., July 11, 1938, Woodson, Allen £ Seibert 1179 (Herb. Missouri Bot. Garden, түре). It is exasperating to have to describe this species merely from several detached corollas found at the base of a tall tree supporting the liana. Efforts to obtain more ample material being futile at the time of collection, complete confidence none the less may be placed in the generic identification of the corollas (which, of course, contain the stamens and stigma as 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 301 is eustomary in the Echitoideae). The anthers, stigma, and arachnoid internal villosity of the corolla are all unmistakable charaeters, although the villosity differs from that of the three other known species of the genus in being limited to the throat. The corollas of F. speciosissima much surpass those of the other known species, and the narrowly tubular throat is quite distinet. Eastern Chiriquí is one of the least known and most promising floristic regions of Panama, as is graphically illus- trated by the discovery of both Prestomia remediorum and Fernaldia speciosissima, literally within a stone's throw of one another. ASCLEPIADACEAE . Масковсерів panamensis Woodson, spec. nov. (fig. 1). Suf- frutex volubilis; ramis dense luteo-pilosis pilis dissimilibus tum brevibus simplicibus tum multo longioribus multicellulari- bus sieut ad petiolos et pedunculos pedicillosque; foliis op- positis petiolatis latissime elliptieis vel obovato-elliptieis apice attenuate subcaudato-acuminatis basi late auriculatis 14-17 ст. longis 9-11 em. latis membranaceis opacis supra sparse strigosis subtus farinulento-puberulis nervo medio subtus luteo-pilosis, petiolo 2 em. longo ; inflorescentiis axillari- bus alternatis umbelliformibus 6-8-floris, pedunculo са. 2 cm. longo; bracteis lineari-lanceolatis foliaceis ca. 1 cm. longis vel infra dense luteo-pilosis; pedicellis 0.8 em. longis similiter vestitis ; calycis laciniis late ellipticis acuminatis foliaceis 0.5- 0.6 em. longis minute puberulis margine ciliatis intus eglandu- losis; corollae salverformis extus omnino glaberrimae pallide luteo-viridis tubo eampanulato 0.9-1.0 em. longo medio inflato ibique ca. 0.8 em. diam. faucibus constrictis minute hispidulis ceterumque glaberrimis, limbo patulo 1.8-1.9 em. lato intus minute hispidulo-papillato са. dimidio lobato lobis obtusis, согопае squamis tubo fere ad fauces adnatis apice subquad- ratis integris introrsum replieatis basi calloso-geniculatis tubo stamineo adnatis; gynostegio subsessili са. 0.45 ст. alto, antheris brevissime appendiculatis basi coronae adnatis, stig- mate obscure 5-lobato са. 0.3 em. diam. ; polliniis oblique pyri- formibus valde compressis са. 0.1 em. longis, caudiculis multo [Vor. 26 302 ANNALS OF THE MISSOURI BOTANICAL GARDEN brevioribus, retinaculo oblongo caudiculum aequante ; folliculis ignotis.—PANAMÁ: thickets near Capira, July 12, 1938, Wood- son, Allen & Seibert 1228 (Herb. Missouri Bot. Garden, түре); liana in thickets, Isla Taboga, July 23-24, 1938, Woodson, А1- len & Seibert 1432. Macroscepis panamensis differs from M. tristis (Seem.) Benth., the only species of the genus previously known from Panama, and apparently collected but once (Seemann 158, Құм % al mie nu DIN E ДЫРҒАН 35 f n XX uA D " S PRU Өр n ч ^ m Ју 4.4 ЙА EA af n ^n QN hk T RARE t MPa D. 6 г. ЖҰҚ 4, "n ЗИ TU HN S А n Ку и: 4 on 4; у ДЕН mi SU Y ME Macroscepis panamensis Woodson, Flower in section, and pollinia. а by A. A. Heinze in the Provinee of Veraguas near Natá), principally in the flowers. The corolla of M. tristis is described as absolutely glabrous, the tube light brown, and the limb dark chocolate. It is surprising that Macroscepis has not been collected pre- viously in the province of Panama, as it is apparently wide- spread. MansDENIA crassipes Hemsl.—panamA: thickets near Ar- raijan, alt. ca. 15 m., June 22, 1938, Woodson, Allen & Seibert 779. This is apparently the first collection of this endemic spe- cies since the discovery of the type specimen by Dr. Sutton ayes. Тһе corolla is greenish-yellow, and the corona seg- 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 303 ments, far surpassing the anther membranes, overhang the rostrate stigma. MarsDENIA MACROPHYLLA (Н. & B.) Fourn.—tos SANTOS: thiekets between Los Santos and Guararé, July 11, 1938, Woodson, Allen & Seibert 1197. As far as I am aware, this is the second time this species has been collected in Panama. I have been unable to examine the first, collected by Seemann (n. 611) near the city of Panamá, but specimens in the her- barium of the Missouri Botanical Garden, cited as of this spe- сіев by Rothe (Engl. Bot. Jahrb. 52: 416. 1915) from Central America, have obtuse or rounded leaf bases and anther mem- branes slightly surpassing the erown segments (used as a key character by Rothe). On the other hand, our specimen has obviously eordate leaves, and the erown segments equal, or even slightly surpass the anther membranes. GonoLosus EDULIS Hemsl.—socas DEL TORO: thickets near Guabito, Aug., 1938, J. H. Permar s.n. Previous records of this plant have indicated its range from southern Mexico to Costa Rica. The material thoughtfully sent by Mr. Permar consists of follicles 7-8 ст. long, approximately 5 em. in diam- eter, which bear conspicuous wings about 1 cm. broad. Сохоговов Monnicheanus Woodson, spec. nov. (fig. 2). Frutex volubilis. Ramuli graciliuseuli ferrugineo-pilosuli in- ferne glabrati. Folia opposita longiuscule petiolata, ovato- oblonga apice abrupte subeaudato-acuminata basi latiuscule eordata 4.9-9.0 ст. longa 2.5—4.5 ст. lata membranacea con- eoloria supra sparse ferrugine hispidulo-pilosula nervo medio basi pauciglanduligera subtus sparsiuscule ferrugineo-strigo- sula; petiolus 2.5-3.0 em. longus pilosulus. Inflorescentia la- teralis alternata longiuscule pedunculata umbelliformis flores medioeres dilute virido-luteos 10-30 gerens; peduneuli 3-5 em. longi minute pilosuli; bracteae lineari-lanceolatae vix 0.2 em. longae; pedicelli 2.5—3.5 em. longi gracili minute pilosuli ; caly- eis laciniae ovato-lanceolatae anguste acuminatae 0.8 cm. lon- gae apicibus valde reflexis glabris caeterumque ferrugineo- pilosulae, squamellis alternatis solitariis dentiformibus ca. 0.15 em. longis; согоПа rotata dilute viridi-lutea extus dense [Vor. 26 304 ANNALS OF THE MISSOURI BOTANICAL GARDEN puberulo-papillata, tubo late conico са. 0.5 ст. profundo basi ea. 0.1 em. diam. intus dense minuteque hispidulo, lobis late ovatis obtuse acuminatis 1 em. longis basi са. 0.7 em. latis apice valde reflexis; gynostegium anguste (ca. 0.2 em.) stipitatum subalato-costatum, stigmate 5-gono са. 0.5 em. diam., antheris brevissime rotundeque apiculatis, polliniis compresse ovoi- deis ea. 0.1 em. longis caudiculas subaequantibus, corpusculo compresse oblongo-sagittato са. 0.025 em. longo; corona ex- terior latissime campanulata 5-partita carnosa saturate lutea RU, M " wb Fig. 2. Gonolobus Момче eanus Woodson, Flower with iri cp removed to show eorona; gynostegium. (Drawing by A. ze.) glabra corolla basi adnata са. 0.7 ст. diam. са. 0.2 em. pro- funda, eorona interior antheris adnata, squamis subreniformi- bus са. 0.25 em. latis 0.15 em. longis patulis ; folliculis ignotis.— Сніногі: thickets, between Finca Lérida and Boquete, alt. 1300-1700 m., July 8-10, 1938, Woodson, Allen & Seibert 1108 (Herb. Missouri Bot. Garden, түре). This species is named in honor of Mr. Tollef B. Mónniche, the master of Finca Lérida and a discriminating and enthusi- astie naturalist, in grateful memory of his innumerable kind- nesses, not only to itinerant botanists, but to the multitude of other pilgrims who make their way, sure of an understanding 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 305 welcome, to his remarkable establishment on the high slopes of the Voleán de Chiriquí. G. Monnicheanus is evidently closely related to both G. edulis Hemsl. and G. dubius Pittier, but dif- fers conspicuously from the former by the remarkable develop- ment of the outer corona, and from the latter in the hispidulous indument of the corolla. CUSCUTACEAE (T. G. Yuncker, Greencastle, Ind.) Cuscuta Woodsonii Yuncker n. sp. (fig. 3). Caules crassi. Flores 4 mm. longi ab floris base ad corollae sinum, subses- siles in dispersis inflorescentibus compactis. Calycis lobi orbi- culari-ovati, late imbricati, obtusi, plus minusve carinati. Corolla campanulata, lobi late ovati, obtusi, aurieulati. Sta- mina lobis corollae dimidio breviora, antherae ovoideae, filamenta subulata, non teretia. Scalae exsertae, oblongae, fimbriatae. Styli ovarium ovoideum circa aequantes, paulo subulati. Capsula depresso-globosa, usque ad 6 mm. diametro, circumscissilia, apertura intrastylaris lata. Semina 4, circ. 2.5 mm. longa, ovalia, hilo oblongo, diagonali. Stems coarse. Flowers membranous or somewhat fleshy, about 4 mm. in length from the base to the corolla sinuses, or 7 em. to the apex of the corolla-lobes when erect, subsessile in scattered, few-flowered, compact clusters. Calyx rather loose about the corolla and scarcely reaching the sinuses, lobes orbicular-ovate, broadly overlapping, obtuse, fleshy in the median and basal parts, becoming thin towards the slightly uneven edges, commonly one or more lobes carinate. Corolla campanulate, lobes about as long as the tube, or slightly shorter, broadly ovate, obtuse, strongly auriculate at the base and broadly overlapping, upright to spreading. Stamens reaching to about the middle of the corolla-lobes, filaments very subulate, flattened (not terete), somewhat longer than the ovoid anthers. Scales prominent, reaching the anthers, oblong, fringed with medium-length processes about the top and sparingly so along the sides, bridged below the middle, some- what thick and fleshy toward the attached basal part. Styles about equal to the ovoid ovary, stout and somewhat subulate. [Vor. 26 306 ANNALS OF THE MISSOURI BOTANICAL GARDEN Capsule depressed-globose, up to 6 mm. in diameter, intra- stylar aperture large, becoming definitely circumscissile when mature although this character may be rather obscure in young fruit, surrounded by the withered corolla which even- tually splits as the capsule enlarges. Seeds 4, about 2.5 mm. long, oval in outline, hilum oblong, oblique.—CmnrniQví: vicin- ity of Casita Alta, Volcán de Chiriquí, alt. 1500-2000 m., June Fig. 3. Cuscuta Woodsonii Yuneker n. sp.: 4, flower x 5; B, opened eorolla x 5; C, opened ^a do id D. capsule x 5; E, seed x 10; F, individual scale x 10; G, ary x 28-July 2, 1938, on a species of Eupatoriwm (7), Woodson, Allen € Seibert 950 (Herb. Missouri Bot. Garden, түрк). The genus Cuscuta appears to be poorly represented in Panama. The only species previously known to occur there is C. trichostyla Engelm. which is represented, so far as I know, by only a single specimen collected by Tweedie. C. Woodsonii differs from C. trichostyla in most of the distinctive characters given below. It appears to be most elosely allied with those 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 307 included in the subsection Subulatae of the section Eugram- mica although the styles do not become so strongly subulate as do those of the species included there. Its chief distinguishing features are the size of the flowers, fruit, and seeds, which are among the largest in the genus; the strongly subulate and flattened filaments; the prominent, oblong scales; and espe- cially the prominently aurieulate corolla-lobes, a character more strongly developed here than in any other known species. BIGNONIACEAE AnRABIDAEA OBLIQUA (НВК.) Bur.—panamA: Gorgona Beach, vie. Gorgona, fr. Aug. 7, 1938, Woodson, Allen Ё Sei- bert 1688. Previously known from Venezuela and Colombia. ARRABIDAEA PLEEI DC.—cocrí: between Aguadulce and An- tón, alt. 15-50 m., July 12, 1938, Woodson, Allen Ё Seibert 1224. PANAMA: beach at Nueva Gorgona, Aug. 7, 1938, Woodson, Allen £ Seibert 1689. Previously known from Venezuela and northern Colombia. LUNDIA CORYMBIFERA (Vahl) Sandw.—ocnimuiquí: banks of the Río Chiriquí, vic. Chiriquí, alt. 15 m., July 11, 1938, Wood- son, Allen Ф Seibert 1178. Although the species has been re- ported from Costa Rica, and occurs frequently from Colombia to Brazil, its existence in Panama has previously been un- known. SaLDANHAEA SEEMANNIANA О, Ktze.—caNAL ZoNE: Victoria Fill, near Miraflores Locks, fl. April 2, 1939, P. H. Allen 1755. PANAMA: Rio de Panamá, near Capira, fl. April 4, 1938, P. H. Allen 730; vic. Capira, fr. July 15, 1938, Woodson, Allen & Sei- bert 1310. cocLÉ: vic. of Penonomé, alt. 15-300 m., fl. Feb. 23- March 22, 1908, В. S. Williams 522 (0. S. Nat. Herb. түре of Adenocalymma cocleensis Pittier). Although previously re- ported from Panama by O. Kuntze, more recently the plant has been described as Adenocalymma cocleensis, a synonymous name. TABEBUIA HETEROTRICHA (DC.) Hemsl.—canau ТОМЕ: Ancon, fl. May 1, 1934, J. P. Keenan 323 (U. S. Nat. Herb.) ; vic. Sum- mit, fl. March 17, 1934, B. Avilla 314 (U. S. Nat. Herb.). РАХ- AMÁ: Alhajuela, Chagres Valley, alt. 30-100 m., st. May 12-15, [Vor. 26 308 ANNALS OF THE MISSOURI BOTANICAL GARDEN 1911, H. Pittier 3501 (Gray Herb.) ; vie. of Chorrera, fl. March 5, 1939, Р.Н. Allen 1698; Sabanas, fl. April 1933, Bro. Paul 307 (U. S. Nat. Herb.). Frequently confused with Tabebuia chry- santha (Jaeq.) Nichols., but distinguishable by having a very densely woolly ealyx, covered with long simple hairs and a much shorter stellate tomentum which ean be seen only by the removal of the longer hairs. The following additional specimens extend the range from Venezuela and Panama to Costa Rica and Nicaragua: совта RICA: without definite locality, fl. April 12, 1923, А. M. Brenes 3876 (Herb. Field Mus.). хісавлатА: south of Managua, fl. March 3, 1922, J. M. Greenman Ё M. T. Greenman 5714 (Herb. Missouri Bot. Garden). Тавевтла Рліммені Rose.—PANAMÁ: vic. Bejuco, fl. Feb. 9, 1939, Р. Н. Allen 1630. Previously known to extend from the state of Michoacan in Mexico to Nicaragua. The species flowers without leaves, making accurate deter- mination impossible at the present time. However, flowers, pubescence and branchlets agree well with typical material of the species. GESNERIACEAE (C. V. Morton, Washington) Товваста Woodsoni Morton, sp. nov. Herba terrestris, cauli- bus non ramosis, apicem versus dense pilosulis ; folia opposita aequalia, subsessilia, petiolo vix 5 mm. longo ; lamina foliorum ovalis, usque ad 15 em. longa et 7 em. lata, acuta, basi longe (3- 4 em.) decurrens, tenuiter membranacea, valde erenata, supra scaberula, subtus praecipue in venis pilosula, venis primariis са. 7-jugis; inflorescentia umbellata, ca. 4-flora, pedunculo communi axillari solitario, 2,3-9,8 ст. longo, pilosulo, apice bibracteato, bracteis linearibus, ca. 7 mm. longis, integris, pilo- sulis, pedicellis 12-13 mm. longis, pilosulis, apice vix inerassa- tis; calyx aurantiaeus, са. 15 mm. longus, campanulatus, ex- terne scaberulo-strigillosus, tubo ca. 12 mm. longo, 10 mm. lato, lobis late triangularibus, са. 3 mm. longis, acutis, glandu- loso-denticulatis, dentibus 1 vel 2 utroque latere; corolla flava et aurantiaea, са. 18 mm. longa, tubulosa, externe pilosa, limbo 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 309 patente, са. 15 mm. lato.—cutrigut: between Río Chiriquí and Remedios, alt. 15—50 m., July 11, 1938, Woodson, Allen & Sei- bert 1195 (U. S. National Herb., no. 1,748,081, түрк). Thad at first identified this collection as Tussacia Friedrichs- thaliana Hanst., but Dr. Woodson, who had collected the latter species twice (nos. 1614 and 1642), told me that in the field he had considered it a distinct species, chiefly on the basis of the differently colored calyx (deep orange rather than pale yel- low). With this in view I re-examined the material and have concluded that no. 1195 does in fact represent an undescribed species. All the collections of 7. Friedrichsthaliana have the corolla glabrous, whereas no. 1195 has a distinctly pilose co- rolla. The different coloration of the calyx is not apparent in dried material, and requires field investigation to determine its importance. Both calyx and corolla evidently vary some- what in color, at least according to collectors’ field notes. Woodson, Allen & Seibert 1642 says, ‘‘calyx yellowish-green, corolla green with orange scarlet lines at base of lobes’’; no. 1614 says, ‘‘corolla orange’’; Kenoyer 536, ‘‘flowers yel- low”; Standley 40952 and 41121, ‘‘calyx green, corolla orange"; Seibert 556, ‘‘flowers orange"; and Seibert 569, ‘flowers orange, streaked in corolla with reddish orange." Конгевла serrulata Morton, sp. nov. Moussonia. Frutex ramosus, caulibus dense hirto-tomentosis, serius glabrescenti- bus, ca. 2 mm. diam., subteretibus; petioli usque ad 12 mm. longi, flavo-tomentosi ; lamina foliorum ovato-lanceolata, usque ad 7.5 em. longa et 4 cm. lata, acuminata, basi rotundata, chartacea, serrulata, supra seabro-pilosula, subtus dense pilo- sula, venis primariis ea. 7-jugis; flores solitarii, axillares, pauci, non pseudospicati, pedicello 15-18 mm. longo, 5 mm. supra basim bibracteato, braeteis subulatis, ca. 4 mm. longis, dense tomentosis; calycis pars adnata campanulata, са. 2.5 mm. longa et 3 mm. lata, dense pilosa, pars libera 7 mm. longa, tubo brevissimo vix 1 mm. longo externe piloso intus glabro, lobis erectis lanceolatis 6 mm. longis et 2.2 mm. basi latis, acumi- natis, apice non recurvatis, integris, margine non incrassatis, externe dense pilosis, intus sparse pilosulis ; corolla aurantiaco- [Vor. 26 310 ANNALS OF THE MISSOURI BOTANICAL GARDEN rubra, 25 mm. longa, tubulosa, tubo basi non calearato, in calyce erecto, basi 5.5 mm. lato, superne gradatim ampliato, vix ventricoso, in fauce non contracto, 9-11 mm. lato, externe dense pilosulo, intus glaberrimo, limbo brevi, lobis erectis, suborbicularibus, ca. 3 mm. longis, erosis, immaculatis; fila- menta in basi corollae tubi inserta, cum tubo non adnata, inter se omnino libera, basin versus pilosa, superne glabra, non con- torta, 22-25 mm. longa; antherae liberae, ca. 2 mm. longae, 1.5 mm. latae, loculis oblongis, non confluentes; ovarium (pars libera) eonieum, brevissimum, dense pilosum; stylus rectus, glaber; stigma stomatomorphum; discus annularis, brevissi- mus, glaber, paullo undulatus.—currieui: Bajo Mono, mouth of Quebrada Chiquero, along Río Caldera, alt. 1500-2000 m., July 3, 1938, Woodson, Allen & Seibert 1609 (U. S. National Herb., по. 1,746,849, түре). Perhaps related to Kohleria elegans (Dene.) Loes. but dis- tinguished by the solitary rather than umbellate flowers, the less sharply acuminate calyx-lobes, the included free anthers and glabrous style. CaMPANEA chiriquana Morton, sp. nov. Еисатратеа. Planta epiphytica, caulibus dense piloso-tomentosis, pilis brunneis multiseptatis ; folia opposita paullo inaequalia, longe petiolata, petiolo usque ad 4 em. longo, dense brunneo-tomentoso ; lamina foliorum ovato-oblonga, usque ad 17 em. longa et 9 em. lata, арісе cuspidato-acuminata, basi euneata in petiolum decur- rens, membranacea, dentata basi excepta, supra pilosula, sub- tus praecipue in venis dense brunneo-tomentosa, venis pri- mariis 7- vel 8-jugis ; inflorescentia umbellata triflora, pedun- eulo communi pendulo, valde elongato, ca. 20 em. longo, dense brunneo-tomentoso, apice bibracteato, bracteis linearibus, ca. 9 mm. longis, dense tomentosis, pedicellis usque ad 5.5 em. longis, dense tomentosis; calycis lobi lanceolati, 8-9 mm. longi, acuminati, non evidenter venosi, dense tomentosi; co- rolla pallide flava, maculata, са. 2.5 em. longa, tubo basi егесіо, valde ventricoso, medio 1.8 cm. lato, faucem versus contracto, externe brunneo-piloso, limbo parvo, lobis rotundatis, intus біаһгів.-снінішгі: vicinity of Casita Alta, Volcán de Chiri- 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III iw | quí, alt. 1500—2000 m., June 28-July 2, 1938, Woodson, Allen Ф Seibert 935 (U. S. National Herb., no. 1,747,001, түрк). Near Campanea Oerstedii (Klotzsch) Oersted, of Costa Riea, but with the pubescence of the stems and under-surface of the leaves more nearly tomentose (as in C. Humboldtii), the calyx-lobes smaller and not evidently nerved, and the corolla more prominently ventrieose. Тһе species of this genus are badly in need of a careful revision. SoLENoPHoRA australis Morton, sp. nov. Frutex 5 m. altus, caulibus atropurpureis obtusangulatis subquadrangulatis, glaberrimis; petiolus usque ad 4.5 em. longus, fere glaber, apicem versus pilis sparsis flaccidis brunneis multiseptatis praeditus; lamina foliorum ovalis, usque ad 15 ст. longa et 8.5 em. lata, acuminata, basi perspicue obliqua, rotundata, papyracea, valde biserrata, supra sparse pilosula, subtus in venis sparse scabro-pilosula, venis primariis са. 9-jugis ; flores subumbellati, peduneulo communi solitario, usque ad 4.5 em. longo, 1.5 mm. diam., compresso, glaberrimo, ca. 3-floro, apice bibracteato, bracteis subulatis erassis ca. 1 cm. longis apice pilosulis, pedicellis са. 1.7 em. longis crassis glaberrimis medio bibracteolatis apice paullo inerassatis; calyx venosus, 3 ст. longus, externe fere glaber, pilis paucis minutis flaccidis multi- septatis apicem versus praeditus, intus dense pilosus, tubo subcylindrico, ca. 2.2 ст. longo, 1 em. lato, basi late cuneato, lobis erectis ca. 8 mm. longis, triangularibus acuminatis mar- gine glanduloso-dentieulatis, dentibus 3 vel 4 utroque latere; corolla externe aurantiaca, intus flava, 8.5 ст. longa, externe parce pilosa, intus glabra, tubo 6.5 em. longo, basi cylindrico, superne gradatim ampliato, vix ventricoso, apice 2.5 cm. lato, in fauce non contracto, limbo patente subbilabiato, lobis late obovatis vel suborbicularibus, utrinque glabris, apice subtrun- catis erosis, intus marginem versus purpureo-maculatis ; sta- mina basi corollae tubi inserta, filamentis latis glabris basi ca. 1.5 em. connatis, antheris apice connatis, 4.5 mm. longis, 4 mm. latis, connectivo hastato glabro, loculis hippocrepiformibus, apice confluentibus, longitudinaliter dehiscentibus; stylus elongatus, compressus, ca. 2 mm. latus, valde pilosulus ; stigma [Vor. 26 312 ANNALS OF THE MISSOURI BOTANICAL GARDEN latum stomatomorphum ; ovarium inferum glaberrimum, pla- centae lamellae utrinque ovuliferae ; disci glandulae 2 posticae, magnae, basi connatae, apice rotundatae, ca. 2.5 mm. longae, ubique dense рПовае.-снінтоті: vicinity of Casita Alta, Vol- cán de Chiriquí, alt. 1500-2000 m., June 28-July 2, 1938, Wood- son, Allen & Seibert 847 (U. S. National Herb., no. 1,746,987, TYPE). Closely related to Solenophora calycosa Donn. Smith, of Costa Rica, but distinguished by the entirely glabrous ovary, nearly glabrous calyx-tube, and glabrous stems and peduncles. CoLUMNEA TOMENTULOSA Morton—socas DEL TORO: Río Cri- camola, between Finca St. Louis and Konkintoé, alt. 10—50 m., Aug. 12, 1938, Woodson, Allen Ф Seibert 1876. Previously known from Nicaragua and Costa Rica. CoLUMNEA panamensis Morton, sp. nov. Eucolumnea. Fru- tex epiphyticus parce ramosus, caule subtereti parce strigoso са. 8 mm. diam., ramulis brevibus, dense antrorse strigosis; folia opposita aequalia, breviter petiolata, petiolo са. 4 mm. longo, strigoso-hirtello; lamina foliorum elliptiea vel anguste elliptiea, 4—4.5 em. longa et 1.5-1.9 em. lata, vix acuta, basi euneata, chartacea, integra, utrinque dense strigoso-pilosa, immaculata, venis primariis 4-jugis; flores adscendentes soli- tarii axillares, pedicello 1.5 em. longo, dense albido-tomentoso ; calycis lobi liberi, lineari-oblongi, са. 1.5 em. longi, 4 mm. lati, acuti, basi angustati, integri, utrinque pilosi ; corolla coccinea, 6.5-7 em. longa, in calyce suberecta, basi postice gibbosa, tubo ea. 3 em. longo, basi ea. 4 mm. lato, sursum ampliato sed non ventricoso, in fauce 10-11 mm. lato, non contracto, externe pi- loso, limbo valde bilabiato, galea erecta integra, 3-3.5 cm. longa, apicem versus ea. 1.4 cm. lata, lobis lateralibus cum galea alte connatis (1.8-2 em.), partibus liberis deltoideis acu- tis, inferiore patente, lineari-oblongo, 1.5-1.7 ст. longo; fila- menta pilosula, apice recurvata; antherae quadratim connatae, mox liberae, 2.6 mm. longae, 2.4 mm. latae, glabrae, loculis oblongis; ovarium dense albo-villosum; stylus elongatus pi- losulus ; stigma stomatomorphum ; disci glandula crassa emar- ginata, са. 2.3 mm. longa et 2.2 mm. lata, glabra.—cnrniQvÍ: 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 313 vieinity of Casita Alta, Voleán de Chiriquí, alt. 1500-2000 m., June 28-July 2, 1938, Woodson, Allen Ф Seibert 860 (Herb. Missouri Bot. Garden, TYPE). Perhaps allied to С. microcalyx Hanst., of Costa Riea, but distinguished by the larger, longer-petiolate leaves, the differ- ent pubescence of the leaves, pedicels and calyx lobes, more deeply cleft corolla, and especially by the puberulous filaments. RUBIACEAE (Р. C. Standley, Chicago) Rupaza isthmensis Standl., sp. nov. Arbuscula 4-metralis ut videtur omnino glabra (flores non visi), ramis gracilibus viri- dibus teretibus, internodiis valde elongatis ; stipulae deciduae, non visae, basi intus setis numerosis inerassatis eorneis palli- dis ca. 2 mm. longis persistentibus auctae; folia medioeria bre- viter petiolata chartacea, petiolo erassiusculo 8-11 mm. longo; lamina ovata vel oblongo-ovata 12-14 em. longa 5-7.5 em. lata anguste longiacuminata, basi obtusa vel rotundata atque bre- viter contracta, supra ораса viridis, nervis venisque prominu- lis, subtus fere concolor subflavescens, costa elevata, nervis lateralibus utroque latere са. 8 prominentibus angulo latius- culo adscendentibus subareuatis remote a margine conjunctis, venulis prominulis laxe reticulatis, axillis nervorum latera- lium poro magno domatiatis ; inflorescentia terminalis parva cymoso-paniculata ca. 2.5 cm. longa et З em. lata pauciflora 18 mm. longe pedunculata, ramis primariis basi non bracteatis, infimis divaricatis rigidis, floribus sessilibus; fructus late ovalis 1 em. longus 8 mm. latus, pyrenis dorso grosse obtuse costatis.—CcANAL ZONE: vicinity of Salamanca Hydrographic Station, Río Pequení, alt. 80 m., July 28-29, 1938, Woodson, Allen & Seibert 1618 (Herb. Field Mus., түре; duplicate in Herb. Missouri Bot. Garden). The only other species of Rudgea previously known from the region, В. cornifolia (Humb. & Bonpl.) Standl. (R. fim- briata Standl.) has practically sessile leaves. In R. isthmensis the remains of the calyx persistent upon the fruit show that the calyx is barely.0.5 mm. in height and remotely denticulate. [Vor. 26 314 ANNALS OF THE MISSOURI BOTANICAL GARDEN CAPRIFOLIACEAE VIBURNUM STELLATO-TOMENTOSUM (Oerst.) Hemsl.—cuirt- осі: thickets between Finca Lérida and Boquete, са. 1300- 1700 m., July 8-10, 1938, Woodson, Allen & Seibert 1103. This species, apparently rather frequent in Costa Rica, has pre- viously been unrecorded from Panama. CUCURBITACEAE Состуввттасва sp. We have been unable to place this speci- men either to genus or to species. Our material consists of a rather slender, scandent herb; stems essentially glabrous; leaves ovate, broadly cordate, acutely acuminate, 12-13 ст. long, 10-11 cm. broad, membranaceous, minutely and sparsely bullate, otherwise glabrous, the petioles very slender, 4 cm. long, glabrous; tendrils opposite the leaves; staminate inflo- rescences spicate-paniculate, in some cases with as many as 6 slender branches 15-30 em. long, bearing occasional reduced tendrils interspersed amongst the distant, nearly sessile floral clusters; staminate flowers greenish-yellow, pedicel 1 mm. long; calyx-lobes 5, equal, broadly ovate, 2.5 mm. long; corolla a fleshy, entire, disc-like ring 0.5 mm. deep, adnate to the base of the calyx; staminal column slender, 1 mm. long, anthers ses- sile, 5, sigmoid. Since pistillate flowers and fruit are lacking, it is scarcely possible to refer the material to either а new ог a pre-existing genus.—BOCAS DEL TORO: vicinity of Nievecita, alt. са. 0-50 m., Aug. 8-19, 1938, Woodson, Allen € Seibert 1841 (unicate, in Herb. Missouri Bot. Garden). COMPOSITAE (S. F. Blake, Washington; Senecio by J. M. Greenman, St. Louis) Senecio Coopert Greenm.—curirigui: Bajo Mona, mouth of Quebrada Chiquero, along Río Caldera, alt. 1500-2000 m., July 3, 1938, Woodson, Allen € Seibert 1014. Previously known only from the highlands of Costa Rica. ГАСЕХОРНОВА panamensis Blake, sp. nov. (pl. 23). Herba perennis pumila pluricaulis ; caules adscendentes са. 1 dm. alti sparsissime pubescentes usque ad capitula foliosi; folia ba- salia spathulata v. oblanceolata ca. 5 em. longa obtusa penni- 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 315 nervia subcoriacea, lamina crenato-serrata breviter ciliata eaeterum subglabra in petiolum subaequalem late marginatum sparse ciliatum angustata; folia caulina ca. 9-14 internodiis saepius longiora, inferiora basalibus similia sed breviora, media et superiora linearia sessilia sparse ciliata prope apicem erenato-serrata, suprema integra; capitula 2-3 parva radiata terminalia et in axillis supremis, pedunculis dense adscendenti-pilosulis quam foliis subtendentibus brevioribus; involueri ea. 4 mm. alti 3-seriati paullum gradati appressi, phyllaria lineari-oblonga obtusa tenuiter subherbacea angus- tissime subsearioso-marginata l-nervia infra ciliata supra ciliolata; radii numerosi patentes parvi lavendulacei; corollae disci flavae (?) ; achenia radii obovata margine erasse nervata breviter rostrata, rostro dense sessili-glanduloso; achenia disci similia, rostro brevissimo annulari; pappus nullus. Plant apparently cespitose; rootstock oblique, about 4 mm. thick; stems several, greenish, subterete, few-ribbed, essen- tially glabrous below, above sparsely puberulous and with scattered long hairs, leafy throughout ; basal leaves few, about 5 em. long including petiole, the blade 2-2.8 em. long, 10-12 mm. wide, erenate-serrate throughout (teeth 5-8 pairs, rather erowded, 1-3 mm. long, obtusely eallous-pointed at the rounded apex, occasionally 1-toothed on the side), short-pilose-ciliate, narrowed into the petiole, this sparsely pilose-ciliate with longer hairs especially toward base; middle stem leaves 1.5- 2.5 em. long, 3-5 mm. wide, sparsely pilose-ciliate with many- celled hairs, toward apex crenate-serrate or serrate with 1-4 pairs of obtuse or acute teeth; peduncles about 5 mm. long; heads (moistened) 12.5 mm. wide; disk (moistened) about 8 mm. wide, 4 mm. high; involucre flattish-hemispherie, about 9 mm. wide, 4 mm. high, the phyllaries 0.6-0.8 mm. wide, some- times purplish-tinged above, sparsely pilose-ciliate toward base, more densely ciliolate toward tip with sometimes sub- glandular hairs, otherwise glabrous; disk flattish, naked ; rays about 57, spreading, 2-seriate, fertile, ‘‘pale pink-lavender,’’ glabrous, the tube 0.3 mm. long, the lamina narrowly oblong or linear-elliptic, 2-dentate or 3-denticulate, 2—3-nerved, 2.6-2.8 [Vor. 26 316 ANNALS OF THE MISSOURI BOTANICAL GARDEN mm. long, 0.6-1 mm. wide; disk flowers about 28, apparently mostly sterile but some perhaps fertile, their corollas gla- brous, 2.2-2.5 mm. long (tube 0.6-0.8 mm., throat campanulate, 0.7-0.9 mm., teeth 5, ovate, acute, spreading, 0.8 mm. long); ray achenes (immature) obovate, compressed, thick-nerved on the margin, nerveless on sides, 2.2 mm. long including beak, abruptly or gradually narrowed into a short thick densely ses- sile-glandular neck 0.4 mm. long, otherwise glabrous, epap- pose; disk achenes (immature) obovate, compressed, thick- nerved on margin, nerveless on the sides, 2 mm. long, 0.7-0.8 mm. wide, slightly narrowed at apex and then slightly ex- panded into a ring-like usually densely sessile-glandular neck about 0.1 mm. high; style branches of hermaphrodite flowers lance-oblong, acute, hispidulous throughout dorsally, without stigmatic lines.—cniniQuí: on potrero, Loma Larga to sum- mit, Voleán de Chiriquí, alt. 2500-3380 m., July 4—6, 1938, Woodson, Allen & Seibert 1047 (U. S. National Herb., no. 1,746,842, түре). The discovery of a species of Lagenophora on the highest mountain in Panama is of considerable phytogeographic inter- est. Lagenophora, a genus of Astereae containing about twenty-three species, has its center of distribution in the Aus- tralian region. Seven species are found in New Zealand and outlying islands, and four others in Australia, one of which occurs also in Ceylon, eastern India, Hongkong, Java, Suma- tra, and the Philippines. Three species have been described from the Hawaiian Islands, two from the Liukiu Islands, and one each from Borneo, New Caledonia, and the Fiji Islands. The half dozen proposed species from South America reduce to three, L. harioti Franch., L. hirsuta Less., and L. nudicaulis (Lam.) Dusén (L. commersonii Cass.), which range from cen- tral Chile (Rancagua) to Tierra del Fuego, one of them occur- ring also on Tristan da Cunha. L. purpurascens Phil. is re- duced to L. nudicaulis by Reiche, and L. lechleri and L. mus- cicola, both nomina nuda made by Schultz Bipontinus, are equivalent to Laestadia lechleri and L. muscicola of Weddell. The three South American species are all всарове or essen- 1939] WOODSON & SEIBERT—FLORA OF PANAMA. III 317 tially so and quite different in appearance from L. panamen- sis. Of the some fourteen species available for comparison, the Hawaiian Г. mawiensis Mann is most similar in appear- ance to L. panamensis, but the former is readily distinguished by its serrate rather than crenate leaves, its glandular-pubes- cent stem, and its much larger solitary heads. SABAZIA TRIANGULARIS var. papposa Blake, var. nov. Achenia radii glabra epapposa vel interdum squamellam unicam ob- longam fimbriatam 0.6 mm. longam angulo interno gerentia; achenia disci erecto-hirsutula papposa; раррі squamellae 5-6 l-seriatae oblongae obtusae fimbriatae 0.8 mm. longae tubam corollae aequantes.—curiRiQvÍ: Loma Larga to summit, Volcán de Chiriquí, alt. 2500-3380 m., July 4-6, 1938, Woodson, Allen £ Seibert 1055 (U. S. National Herb., по. 1,746,843, TYPE). In the type of Sabazia triangularis Blake (Pittier 3109, El Potrero Camp, Voleán de Chiriquí, alt. 2800-3000 m.) the ray achenes are glabrous and epappose, the disk achenes hispidu- lous and likewise epappose. Тһе differences between the typieal form and the variety are much like those separating Sabazia pinetorum Blake and its var. dispar. PIQUERIA TRINERVIA Cav. var. LUXURIANS Kuntze—cuiriqui: Loma Larga to summit, Volcán de Chiriquí, alt. 2500-3380 m., July 4-6, 1938, Woodson, Allen & Seibert 1044. Apparently the first record for any form of the genus in Panama. 'The variety was previously known from Costa Rica; the typical form ranges from Mexico to Costa Rica, and is also recorded by Robinson from Haiti. Се 4 ma^ E ANN. Мо. Bor. GARD., VOL. 26, 1939 PLATE 20 WOODSON AND SEIBERT—FLORA OF PANAMA EXPLANATION OF PLATE PLATE 21 1. Malaxis Woodsonii. Plant natural size. 3. Notylia Cordesii. Flower x 4. 4. Notylia Cordesii. Labellum x 8. (Figures drawn from the types by G. W. Dillon.) 7972) ава с дљ “7 Т i "а i ырк ЕТ ANN. Mo. Bor. GARD., VoL. 26, 1959 PLATE 21 WOODSON AND SEIBERT—FLORA OF PANAMA EXPLANATION OF PLATE PLATE 22 Maytenus Woodsoni Lundell. From type specimen, Woodson, Allen and Seibert 1065, in Herbarium of the University of Michigan, x 15. џ " 2 ANN. Мо. Вот. GARD., Vor. 26, 1939 PLATE 22 WOODSON AND SEIBERT—FLORA OF PANAMA Lagenophora panamensis Blake (natural size). ы «Ро EUN Ру PLATE 23 ANN. Mo. Bor. GARD., VoL. 26, 193 WOODSON AND SEIBERT FLORA OF PANAMA THE GENETIC COEFFICIENTS OF SPECIFIC DIFFERENCE EDGAR ANDERSON Geneticist to the Missouri Botanical Garden Professor of Botany in the Henry Shaw School of Botany of Washington University AND RUTH PECK OWNBEY Formerly Jessie В. Barr Research Fellow in the Henry Shaw School of Botany of Washington University For the precise study of evolution of populations, races, or species, nearly every problem sooner or later requires some measurement of the morphological divergencies in the groups under observation. This is equally true and the problem is fundamentally the same whether one be studying very closely related species of Drosophila (Dobzhansky and Mather, ’39), varieties of gall wasps (Kinsey, unpublished), fields of irises (Anderson, ’36a), or the races of man (Pearson, ’26, and vari- ous other authors). It is usually taken for granted in such studies that any measurable feature or features of the organ- ism will serve equally well as a measure of likeness if only the records be made with care and treated with the precise methods of biometry. Improvements have recently been made by con- sidering differences in groups of measurements, the data be- ing combined crudely (Anderson, 'Зба, ’86b, Anderson and Hu- bricht, '38) or by refined biometrical techniques (Fisher, '36b). These methods are all based on the tacit assumption that species differences are expressed more or less at random. A study of such differences has convinced us that their morpho- logical nature renders these methods relatively inefficient. Species do not differ in a random manner. They differ in a peculiar and subtle way. If any two closely related species of the flowering plants are examined critically it will be found that they differ as a whole by two sets of harmonically inte- grated tendencies (Anderson and Whitaker, 7394). Such a con- clusion, however, is of little use in quantitative work. In sec- tion I, therefore, there is developed a precise mathematical ANN. Mo. Bor. GARD., Vol. 26, 1939 (325) [Vor. 26 326 ANNALS OF THE MISSOURI BOTANICAL GARDEN expression for the difference between ‘‘two sets of harmoni- cally integrated tendencies." The application of this formula is illustrated in section II, where an attempt is made to analyze the differences between Nicotiana alata and У. Langsdorffit and to show how, from an estimate of their ‘‘genetic co-effi- cients,” an efficient measure of their total difference could be developed. I A GENERAL FORMULA FOR THE EFFICIENT MEASUREMENT OF SPECIFIC DIFFERENCES It might seem impossible to formulate any mathematical definition of species differences broad enough to apply to or- ganisms as different as flowering plants, insects, and verte- brates. A little reflection, however, will remind one that the gene-chromosome-cell relation is fundamentally the same in these various organisms and that species differences, in so far as they rest on the gene-chromosome-cell system, may be ex- peeted to exhibit certain general features. Closely related species or races may be conceived as made up of a large number of characters, the number considered in апу particular instance depending upon the viewpoint of the ` observer. Any two closely related species, however, will have the same sets of characters which differ only in their propor- tionate development. In studying races of mankind, for in- stance, there might be considered the head, the neck, the trunk, the arms, and the legs of the two races. If the set of charac- ters were subdivided into such categories as fingers, ears, etc., it would still be possible to observe the same set in both races. We may therefore define the gross morphology of any or- ganism as being the sum of a set of characters: Organism = A + В+С+р+Е+Е+...... +N. In во far as species differences rest in the germ-plasm, the basie differences between the two species will not be differences in these characters but in the germ-plasm which give rise to them, and they сап be thought of as made up of a set of differences between corresponding factors of the germ-plasm. These factors in the germ-plasm we shall write а, Б, с, д, e, ...... n for one species, and a’, b’, е”, ^ Желете n' for the other. Some of these may relate to ргос- 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 397 esses so general that they are expressed in every character (ав, for instance, a gene affecting cell division or wall formation). For such factors we shall use the first letters of the alphabet and we may write the first species as: (abe ...... ) А + (abe E JB + (abe ......)O + (abe ......)D H... у * Taba pO )N, while the second species will be written: (ае ГЕ JA + аб... ЈВ + (Ue S.T ОЕК e зен )р+...... + (ае ......) №. The dots within the par- entheses represent additional factors affecting all the char- acters. Other factors will affect only similar characters, as, for instance, the leaf and the calyx in flowering plants, or hand and foot in vertebrates. For them we may use the middle letters of the alphabet. There are probably also elements in the germ- plasm which affect only single characters. If we use letters at the end of the alphabet for them, then the total morphological difference between two related species is described by the fol- lowing mathematical expression: (abe... m..x..JA+ (арс... гу ВО... Ћ.. ОВЕ. s я (ве... р. №. Dp Бе ..)А + (аре... ..у'..)В + (аре ШТІ... PAR OG a 20, ОУ: EN From TE it follows that a set of observations upon А or upon А and B will probably be an inefficient way of getting at fundamental differences between the two species. That is to say, instead of comparing two races of men by their skulls alone, or two species of Acer by their leaves, we should first at- tempt to determine the most efficient way of measuring the coefficients which affect skull, trunk, and appendages in man, or leaf, stem, and inflorescence in Acer. What is needed is the most efficient way of measuring (a – a’), (b-b), (e- e), ...... (n—n’). These genetic coefficients of specific difference (a vs. a’, b vs. ћу, e vs. с”, ete.) cannot be determined from casual in- spection. While their determination is a much more simple matter in the flowering plants than in the insects or verte- brates, it will even there require detailed observation and ex- periment. How to measure any particular specific difference is a research problem which should be undertaken before one proceeds to the actual measurement. [Vor. 26 328 ANNALS OF THE MISSOURI BOTANICAL GARDEN IL AN ESTIMATE OF THE GENETIC COEFFICIENTS WHICH DIFFERENTIATE NICOTIANA ALATA FROM N. LANGSDORFFII The species chosen for comparison were Nicotiana alata and №. Langsdorfhi. They were selected because (1) they are easily grown for observation and experiment, (2) a large body of genetic and cytological data is already at hand concerning their behavior in crosses and back-crosses (East, 716, Sachs-Ska- linska, '21, Brieger, '35, Smith, '37, Avery, '38, Anderson, 739), (3) an estimate of their genetic coefficients was desired as the basis for analysis in further erosses. Nicotiana alata is the night-blooming species with large white flowers, known to gar- deners as №. affinis. №. Langsdorffi is a smaller, chunkier species, with bright green flowers and blue pollen. Representa- tive flowers of each are illustrated in plate 24, A-C. Seed of N. alata was obtained from the Palmer Seed Company of St. Louis. Some of the plants bore pale pink corollas, probably the result of hybridization in cultivation with X Nicotiana Sanderae (- N. alata X N. Forgetiana). The strain of N. Langsdorffii was kindly supplied by Dr. Н. Н. Smith of the О. 5. Department of Agriculture. The known facts of the rela- tionship and distribution of the two species have been sum- marized by Avery (738). Тһе points which concern us here are that both species are diploid members of the 9-chromosome group of Nicotiana, and that they are both native (or are at least widely distributed) in a large region in central South America. From a study of the meiotie configurations of their hybrids Avery concluded that the gross differences in their chromosome complements were confined to two translocations in three pairs of chromosomes. Like some of the evidence sub- mitted below, this fact supports (though it does not prove) Anastasia's speculation (714) that N. Langsdorffii may be the result of a eross between N. alata or a closely related species and some such member of the 24-chromosome group as N. rustica, by which a few segments of rustica germ-plasm be- came incorporated in an alata genom (Avery, '38). If this is indeed the relationship between N. alata and N. Langsdorfii, the case, while exceptional, is not unique in our opinion. There 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 329 are a number of genera of flowering plants in which the morphological resemblances between the species would indi- eate similar relationships. 1. Cell size.—In searching for the fundamental genetie co- efficients which differentiate these two species, one of the most obvious places to look is the cell itself. If there are outstand- ing differences in cell size, cell uniformity, or in the develop- ment of the cell wall, they should be comparatively easy to de- tect. An inherent cell-size difference, for instance, should manifest itself in a consistently larger size of one species, even in those organs in which there are no obvious differences in proportion. Even a superficial examination will show that g. l. А, corolla-tube of Nicotiana alata (above) and of N. Langsdorffit (below) ; B, corolla-throat of N. alata (above) and of N. Langsdorffi (be- low). All figures drawn to the same scale. Nicotiana alata is generally larger throughout than is N. Langsdorffii. The shape differences in the corolla are con- fined to the base of the tube and the limb. The throat of the corolla, although complex in shape, is of practically the same proportion in the two species, and is roughly half again to twice as large in N. alata as in N. Langsdorffit (pl. 24, and fig. 1, B). The pedicels, the cross-section of the style, the capsule, and the seeds show the same relationship. Histological exami- nation shows that the surmise of a fundamental difference in cell size is probably correct. While measurements of whole tissues were not undertaken, examinations were made in all those organs which seemed to have about the same propor- tions. Camera-lucida drawings are presented in fig. 2. It will be noted that, in each, the cells of N. alata are larger than those | of N. Langsdorffii and that in each the ratio of their diameters VoL. 330 ANNALS OF THE MISSOURI BOTANICAL GARDEN y A а, " 0 2 E о 9 Фо Е о Fig. 2. tiana alata and У. L dorffii: epidermal cells from base of eo кай 1 та plastids drawn in E and F show relative size, but not relative num- ber or distribution. 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 331 is roughly from 1:1.5 to 1:2. Furthermore, this ratio agrees with the size differences of the organs concerned. Note par- ticularly the pedicels, the corolla-throats, the pollen, and the seeds (fig. 3 and pl. 24). As a working hypothesis we may therefore conclude that one of the fundamental differences between N. alata and N. Langs- dorffit is cell size, and that it is apparently expressed through- out the organism. Its expression is certainly modified by lo- calized differences in cell elongation, as will be shown below, and perhaps by differences in cell number, though we have as yet little definite information on that point. А В Fig. 3. Pollen grains of (A) Nicotiana alata, and (В) N. Langsdorffit. 2. Cell elongation.—The most striking difference in flower shape between the two species is the constricted portion of the corolla-tube below the point where the stamens are in- serted. In Nicotiana Langsdorffii this is so short that it cannot be seen without removing the calyx. In N. alata it is much longer than the throat (pl. 24, A, C, and fig. 1, A). Histological examination showed that the difference is mainly due to cell elongation. Allowing for the basic difference in cell size (see above) the cells of the tube in N. alata are pro- portionately no wider than those іп №. Langsdorffix though they are many times as long (Nagel, '39). It seemed probable that such a difference should be expressed elsewhere through- out the plant, and even a cursory examination showed this to be the case. Nicotiana alata is not only a somewhat larger plant [Vor. 26 332 ANNALS OF THE MISSOURI BOTANICAL GARDEN than N. Langsdorfflii; it has a general tendency to be somewhat more elongated. It has narrower leaves (largely due to more elongated petioles), longer internodes, narrower bracts, longer calyx-lobes, a much longer style, and a more pointed ovary, re- sulting in elongate lobes of the ripened capsule (pl. 24, D, E). It seemed probable that all of these correlated differences rest on a difference in the mechanism of cell elongation. This point has very kindly been investigated by Miss Nagel, whose results are reported in the accompanying paper. She finds that there is a basic difference in the auxin response of the two species. Nicotiana Langsdorffi apparently inactivates auxin very readily and therefore shows little or no response even when it is supplied artificially in various ways. Nicotiana alata, on the other hand, does not inactivate it so readily and, in stem, leaf, and flower, shows even greater elongation when additional auxin is supplied artificially. It therefore seems quite defi- nitely established that one of the differentiating genetic co- efficients affects the auxin mechanism, probably by bringing about greater auxin inactivation in one species than in the other. It seems quite probable that several of the coefficients listed below may be only accessory manifestations of this same auxin difference. This is particularly true of number 3, geo- tropic response, and number 4, leaf-vein angles. 3. Geotropic orientation of appendages.—Appendages of the axis, and its own branches, diverge at a more acute angle in Nicotiana alata than in N. Langsdorffit. This angle divergence is roughly the same in leaves, pedicels, bracts, and branches of the inflorescence (fig. 4). It has been well established that the geotropic response of flowering plants is accomplished through auxin regulation (Dolk, '86). Whether or not the difference in appendage orientation is due to the same auxin-mechanism difference as that affecting corolla-tube elongation we have as yet no means of proving. 4. Leaf-vein angles.—The angles made by the side-veins with the midrib of the leaf are also more acute in N. alata than 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 333 40 60 80 Fig. Frequency dis- tributions showing angle of divergence of the sec- nda of the leaf blade, in Nico- tiana alata (solid line) and pu (broken ‘line The ~ bers represent the ME egre 60 in de ty ҚАМ distributions showing à yr» of divergence of leaf, (B) flowering pedicel, and (С) branch of -= inflorescence. The solid line, in each case, represents аме ana alata, the broken line, №. Langsdorffit. The numbers along the base fase rep- resent the angles of divergence, in degrees. in N. Langsdorff (fig. 5). While it is probable that this dif- ference is related to auxin concentrations, further experimen- tation will be required to discover its relation to geotropism and elongation in the appendages. 5. Plastid color.—The most conspicuous difference between the two species is the color of the flowers. The corollas of N. alata are a clear ivory-white within, somewhat tinged with green on the outside. Those of N. Langsdorffit are bright green [Vor. 26 334 ANNALS OF THE MISSOURI BOTANICAL GARDEN on both sides. Mieroscopieal examination shows this differ- ence to reside in the plastids, which are ivory in the former and green in the latter. While this difference is most extreme in the flower it is also expressed in other parts of the plant, notably in the midribs of the leaves and in the pedicels. These are ivory at maturity in N. alata and green in N. Langsdorffii. We there- fore conclude that one of the genetic coefficients which differen- tiate the two species is the ability to develop ivory rather than green plastids under certain conditions. 6. Peripheral foliar development.—One of the most striking differences between the flowers of N. alata and У. Langsdor ffi occurs in the corolla-limb. In the former species it is larger and deeply lobed; in the latter, small and almost unlobed. The difference in cell size, discussed above, would account for not more than half of the difference in limb size. That there is evidently a genetic coefficient in N. alata producing continued development of the marginal tissue in foliar organs is sug- gested by a comparison of the leaves of the two species. Those of №. Langsdorffii are characteristically flat. In those of N. alata the margin has developed to such an extent that it cannot be accommodated in a flat position and is strongly waved. We therefore suggest that one of the differentiating genetie со- efficients we are seeking affects the development of the margin in leaf and corolla. 7. Basal foliar development. А further conspicuous differ- ence between the species is in the shape of the corolla limb, which is deeply lobed in N. alata and so slightly lobed in N. Langsdorffii that the limb sometimes has a slightly greater diameter at the sinuses than at the apex (which can still be recognized, however, by the veining pattern). Part of this dif- ference in shape is a physiological necessity of the greater size and is not due to specific shape differences. It has already been shown (Anderson, 739) that in the genicly uniform F, be- tween the two species there is a correlation of .3105 + .1077 between the degree of lobing and the limb width. An examina- tion of the limb offers a simple explanation of this correlation. 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 335 Тһе main vein is down the center of the lobe, and it might be expected that with increased growth of the limb there must of necessity be a greater increase proportionately at those points near the food supply (the tips of the lobes) than at those points which are remote from the food supply (the sinuses). There is evidence, however, that there are factors in Nicotiana alata making for accentuated lobes other than those concomitant with the increase in size. The К, correlations between lobing and limb width are much greater (.7186 + .0300) than those of the F,, indicating a genetic correlation as well as a purely physiological one. Furthermore, second-generation hybrids with limbs of the same size differ among themselves in the amount of lobing of the corolla. Nicotiana alata therefore dif- fers from N. Langsdorffit not only in the size of its limb but in a tendency for the limb to grow more towards the tip and less towards the base. It seems not impossible that this same tendency may also operate in the other foliar organs. The leaves of the two spe- cies differ in length of the petiolar portion (as has been dis- cussed above) and in shape of the basal portion of the blade, which is proportionately wider in N. Гатдзаотјји. И two leaf blades of about the same size and age are selected and laid side by side it will be seen that their tips are very similar and that most of the difference in blade shape is due to the wider base. The leaf of N. Langsdorffii is furthermore more decurrent on the stem than is that of N. alata. As a basis for further experi- ment we would therefore suggest that one of the genetie co- efficients distinguishing the two species is a factor for greater basal development in foliar organs. Its chief effect in N. Langsdorffii is to make the blade proportionately broader at the base and, by exerting a similar effect upon corolla-lobes, to lessen the lobing of the corolla. The evidence for such a co- efficient is much more speculative than that for the coefficients previously discussed. 8. Pollen color.—The pollen of N. Гатдзаотј is bright blue, that of N. alata is ivory-colored. Smith has shown (737) that the produetion of blue pollen is due to two complementary [Vor. 26 336 ANNALS OF THE MISSOURI BOTANICAL GARDEN genes which are independent of the gene for green plastid color. 9. Time of blooming.—The flowers of N. alata begin to open late in the afternoon and elose, as if wilted, during most of the day. While we have made no precise experiments, this is ap- parently correlated with both light and temperature. On a dark day, or indoors, the flowers of N. alata may remain more or less expanded throughout the day. Nicotiana Langsdorffii, on the other hand, is a day-blooming species, though it wilts in strong sunshine even more readily than other day-blooming Nieotianas. It seems possible that this difference between the species may be another expression of the plastid difference dis- eussed above. If this be true, it should be possible to establish the fact by a careful study of second-generation and back- eross individuals. 10. Scent.—The flowers of N. alata are delightfully scented, partieularly when they first expand in the early evening. Those of №. Langsdorffii have little or no odor. 11. Inflorescence.—' Typical inflorescences of each species are diagrammed in fig. 6. Тһеу exhibit at least two kinds of dif- ference between the two species: degree of branching, and de- terminate vs. indeterminate nodes. Nicotiana Langsdorffii shows a much higher degree of branching than does N. alata. It is difficult to score definitely because in both species the amount of branching is affected by the food supply. Starved in а two-inch pot even N. Langsdorffii will have a simple stem. When grown in four- or five-inch pots, however, it always shows numerous well-developed secondary axes and at least a few of the third and fourth order. Nicotiana alata often shows only a few secondary and no tertiary axes. Nicotiana alata is apparently indeterminate, but there is no transparent relation between flowers and bracts. In N. Langs- dorffii every axis, whether primary, secondary, or of a higher order, is terminated by a flower. Тһе terminal flower on the primary axis is the first to bloom, followed by those terminat- ing the two upper secondary axes. These facts would indi- cate that the inflorescence is in part truly determinate. On PAK. agio eA a 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 331 the other hand, these terminal flowers are not subtended by bracts, but small bracts, usually without flowers, occur a short way up each of the secondary axes. This might indieate that the terminal flowers are falsely determinate. Whether the de- 6. Inflorescenee diagrams of (A) Nicotiana alata, and (B) N. Langs- aoc Тһе yo of di ivergence ы -— pedicels, and branches are aver- age ones for the two species. No attempt is made to show си length of internodes, leaves, or pedicels. Broken lines indicate continuation of the axes. terminateness of N. Langsdorffii is affected by coefficients which are expressed elsewhere in the organism cannot be ascertained without further experiment. From what is known about such matters it would seem highly possible that the de- gree of branching might be affected by the auxin mechanism. [Vor. 26 338 ANNALS OF THE MISSOURI BOTANICAL GARDEN Cell shape.—There are various differences in cell shape between the two species, particularly in the cells of the epi- dermis. Not enough work has been done to show whether or not these differences can be reduced to differences in one or a few basie coefficients. Zygomorphy.—The flowers of both species are slightly zygomorphie, though in N. alata it is the corolla-limb which shows its bilateral symmetry most strikingly, while in А. Langsdorfhi the expression of this tendency is stronger in the corolla-tube and throat. It is quite probable that these may be further manifestations of the basis for the vein-angle and leaf- angle differences. In addition to the differences discussed above there are a number of minor ones whose expression is apparently limited to a single organ. Further genetical and physiological experi- mentation may show that some of these are further effects of the coefficients described above. TABLE I SUMMARY OF THE GENETIC COEFFICIENTS DIFFERENTIATING N. ALATA FROM N. LANGSDORFFII. "x," ORGANS IN WHICH THE ACTION OF THE GENETIC COEFFICIENT IS EVIDENT, '*," THE ORGAN IN WHICH ІТ CAN ROBABLY BE MEASURED MOST EFFICIENTLY Vegetative Reproduetive phase 4 Е coefficients ~ Genetic --- this may be eoeffieients "S % Я Я _ | afurther = % = a E E 5 E Е г E expression 4 d 4mmnobbB35ok (1) Cell size х" = ЕЖ = хх (2) (2) Cell elongation Tox X x Ж (3) Geotropie response x. - r x * ? ? (2) (4) Leaf-vein angles Ж ? (5) Plastid col x x э. X А (6) Foliar periphery x х Ж i x (7) Foliar base Ж x x ” (9) (8) Pollen eolor " (9) Time of blooming T pM (5) (10) Scent ы (11) Inflorescence * (2) 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 339 A tabular summary of the coefficients which we have been able to detect so far is given in table r. It will be seen that eleven different coefficients have been recognized. Further work may possibly add a few more and will probably reduce certain of those listed as separate to a common coefficient. While there may well be differences which are not accounted for by the action of these eleven, they are certainly responsible for most of the total hiatus between the two species. In this particular problem, as stated above, an estimate of the coefficients was desired as an aid in the genetic analysis. It may be well, however, by way of example, to point out how the estimate might have been used had our concern been the measurement of differences in populations involving the two species. Only two of the coefficients would be difficult to score, (9) and (10). The effects of both of these coefficients are greatly influenced by environmental factors, and it is also dif- ficult to record them objectively. Of the remaining nine, one, (8), is seemingly manifest only in the pollen, and one, (11), only in the branching of the inflorescence. They would ob- viously have to be measured at those places. Coefficients (1) to (7), however, are all manifest in both the leaf and the flower, and each of the seven is expressed in various other ways. With the above estimate as a guide we should be able to decide where these seven differences might be measured most efficiently. Were it not for this previous analysis it might have seemed that the leaf is the most promising organ for measurement. It is practically two dimensional, and its characteristics can all be expressed in simple quantitative terms by measuring and counting the veins and the vein angles. The leaf could further- more be measured on young plants which had not yet reached the reproductive phase. The above analysis demonstrates, however, that the divergence between the two species can much more efficiently be measured in the flower. Though all seven coefficients are expressed in the leaf, its shape is the result- ant of four of them, cell size, cell elongation, basal growth, and peripheral growth. Each of these can be determined in the flower with a single measurement, whereas in the leaf the raw [Vor. 26 340 ANNALS OF THE MISSOURI BOTANICAL GARDEN measurements are a complex resultant of all four. Further- more, nearly all the veins and vein angles would have to be measured and given a thorough statistical treatment before they would be anywhere nearly as useful as the raw data ob- tained from the flower. Тһе complexities of integrating and in- terpreting leaf measurements are illustrated in the statistical papers of Czeezott and her associates (Czeezott, '36, Jentys- Szaferowa, '38, Wisniewski, 732). The procedure suggested by the above analysis would be much simpler. Тһе seven coefficients could best be measured as follows: (1) Cell size.—While this is expressed throughout the plant, it can most efficiently be measured in those organs which are not affected by the other coefficients. The diameter of the pedi- cel or the diameter of the style might perhaps serve but those organs are so small that errors of measurement would be pro- portionately large. The throat of the corolla (from the inser- tion of the stamens to the angle marking the limb) is roughly the same proportion in both species (fig. 1, B), its cells seem to be of the same shape, and the limits to be measured are quite definite. (2) Cell elongation.—This might also be measured in vari- ous parts of the plant, or it might even be measured by testing the effect of tissue extracts upon any standardized auxin indi- eator. The constricted tube of the corolla, however, offers the simplest measurement. In №. Langsdorffit it is less than half a em. long. In N. alata it is 6 to 9 em. While a small portion of this difference is due to (1), the difference in cell size, it is so slight as to be almost negligible by comparison. One measure- ment on the tube therefore is an almost perfect reflection of the basic difference in cell elongation between the two species. (3) Geotropic response.—The angle of inclination made by the leaf, the branches of the inflorescence, or the pedicel of the flower might be measured. There is considerable variation among the leaves, however, depending upon the age of the plant, the time of day, the health of the plant, the position with 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 341 relation to the rosette, ete. A more comparable measure of (3) can be made by recording the angle made by the pedicel at the time of anthesis. (4) Leaf-vein angles.—These are easiest to measure on the largest leaves. Тһе best record we have been able to work out is the angle of the first vein above the petiolar portion of the leaf, on the first or second leaf above the rosette (these leaves are often injured, and more consistent results are obtained by choosing arbitrarily the most symmetrically developed of the two). (5) Plastid color.—While this difference can be seen along the petiole and on the pedicel, particularly in old specimens, it is much more dramatic in the flower. It is there most readily scored on the inside of the flower. As has been previously re- ported (Anderson, ’39), it is easy to recognize three grades of plastid color in the hybrids. (6) Foliar periphery.— Exc 2v x1 ael TU ico | 1939] ANDERSON & OWNBEY—SPECIFIC DIFFERENCE 345 undertaken in a genus such as Nicotiana in which both the leaves and flowers are large and clearly differentiated into definite tubes, limbs, petioles, etc. While it would have to be frankly provisional it would provide a view of phylogeny which would be dynamic rather than static. SUMMARY 1. From previous studies of closely related species it had been concluded that differences between such species are to be sought not in any one charaeter but in harmoniously inte- grated tendencies (genetic coefficients) expressed more or less throughout the entire organism. A simple mathematical no- tation is developed for expressing the resulting morphological hiatus between two species. 2. By way of example, an estimate is made of the genetic co- efficients which differentiate Nicotiana alata from N. Langs- Дота. Eleven such coefficients are suggested, the most im- portant of which affect cell size, plastid development, and the auxin mechanism. 3. Estimates of genetie coefficients might be used in a num- ber of different fields of biology. Their application to the fol- lowing three problems is discussed: (1) The efficient measure- ment of specific and subspecifie divergence; (2) The genetic analysis of differences between species; (3) The determina- tion of phylogenetic patterns. BIBLIOGRAPHY раа G. E. (714). coe Nieotianae. R. Ist. Sper. Scafati, Boll. Tec. Colt. echi 13: 51-2 PR in Edgar og The species problem in Iris. Ann. Mo. Bot. Gard. 23: 4 9. — —, (736b). Hybridization in American Tradescantias. Ibid.: 511-525. — (739). Recombination in species crosses. Genetics 24: 668—698. —— —,and Leslie Hubricht (738). The American sugar maples. I. Phylo- genetic iei omis: as deduced from a study of leaf variation. Bot. Gaz. 100: 819-323. —————————, and Thomas W. Whitaker (734). Speciation іп Uvularia. Jour. Arn. Arb. 15: 28-42. Avery, Priseilla (738). Cytogenetie evidences 5 Nicotiana phylesis іп the alata- group. Univ. Calif. Publ. Bot. 18: 153- ГУог. 26, 1939] 346 ANNALS OF THE MISSOURI BOTANICAL GARDE гісі F. G. (735). Genetic ызын s of the cross between the self-fertile Nico- а Langsdorfii and the self-sterile N. Sanderae. Jour. Genetics 30: 79-100. Ж, Hanna (736). А кен on the UE: of the leaves of beeches: Ж. orientalis Lipsky, F. silvatica L., and intermediate forms. Part II, pp. 1-68 (Polish, English Summary). арна from Ann. Soc, Dendrol. Pologne 6 Dolk, H. E. (736). Geotropism and the growth substance. Rec. Trav. Bot. Néerl. East, E. M. (716). Inheritance in crosses between Nicotiana Langsdorffii and Nicotiana alata. — 1: 311-333. Fisher, В. A. (736a). “Тһе coefficient of racial likeness’’ and the future of eraniometry. Roy. Anthrop. Inst. 66: 57-63. ‚ (736b). The use of suos measurements in taxonomic problems. Ann Зарба, 7: 179—188. Jentys- Sraferowa, Janina (738). — studies on the collective species II. The possibility o Legen e between speeies Betula verrucosa Ehrh. and Betula pubescens h. (Polish, English translation). Inst. Rech. Foréts, Dom. Warszawa, Ser. mj No. 2 бин 1–8 2 "м. каак (739). Morphogenetie differences bet Nicotiana alata and MEA as iam: by their response зра. песн acid. Ann. Mo. An . Gard. 26: 349 1939. Pearson, Karl (726). On the abled of racial likeness. Biometrika 18: 105—117. Sachs-Skalinska, M. (721). Recherches sur les hybrides du Nicotiana, Mém. Inst. nét. de l'École Sup. d'Agri. à Varsovie 1: 47-122. Smith, Harold H. C81). d of corolla color in the cross Nicotiana Langs- dorfii by N. Sander Geneties 22: 847-360. Тһе relation between genes affeeting size and muri in жейік: species of Nicotiana. Ibid.: 361—375 big temo Tadeusz (732). Biometrische Untersuchungen über die Variabilität der e (Fagus Wipro А in Polen I, pp. 1-27 (Polish, German summary). Re ры ы Sylwan 6: EXPLANATION оғ PLATE PLATE 24 A. Flower of Nicotiana alata (x То). (x б. Seed of №. Langsdorffii (x ad 50). ANN. Mo. Вот. GARD., VoL. 26, 1939 PLATE 24 ANDERSON AND OWNBEY—SPECIFIC DIFFERENCE MORPHOGENETIC DIFFERENCES BETWEEN NICOTIANA ALATA AND N. LANGSDORFFII AS INDICATED BY THEIR RESPONSE TO INDOLEACETIC ACID LILLIAN NAGEL Teacher of Biology, Southwest High School, St. Louis, Mo. INTRODUCTION An unusual opportunity for the application of the present knowledge of hormones to the investigation of morphogenetic differences between two closely related species is afforded by Nicotiana alata and Nicotiana Langsdorffii. The flowers of the two species are similar, but the difference in the size of the co- rolla parts suggests a possible interpretation in terms of hered- itary response to growth substance. One of the chief differ- ences lies in the constricted part of the corolla-tube (pl. 25, fig. 1). In N. alata its length is at least fifteen to twenty times that of №. Langsdorffii, whereas the whole corolla in the former is only four or five times the length of thelatter. The epidermal cells of the tube of N. alata are extremely long; those of N. Langsdorffi, relatively short. The work on several known genetie dwarf races of corn by van Overbeek (735, '38) indicates that the varietal differences are due to genetic differences which regulate production, use, and inactivation of auxin. The experiments on Epilobium hy- brids by Schlenker and Mittman, cited by Went and 'Thimann (737), suggest this same relationship. If this hypothesis holds true for species of N?cotiana and the differences between them are due to differences in amount of hormone produced, then auxin should prove to be a limiting factor in N. Langsdor ffi and its application to the corollas of this species should then cause an increase in size. If differences are due to differences in ability to use growth substance, then auxin should be a limit- ing factor in N. alata and additional amounts should inerease ANN. Mo. Bor. GARD., Vol. 26, 1939 (349) [Vor. 26 350 ANNALS OF THE MISSOURI BOTANICAL GARDEN growth, whereas N. Langsdorffii would probably inactivate the hormone. On the supposition that the fundamental morpho- logical distinctions between the two species are linked to ge- netie differenees in ability to use or produce hormone, the fol- lowing experiments were carried out. MATERIALS Nicotiana alata Link & Otto and Nicotiana Langsdorffit Wienm. belong to a phylogenetic unit within the genus referred to by Priscilla Avery (738) as the ‘‘alata-group.’’ This is а group appearing to have a center of distribution in the Brazil- ian and northern Argentine area, and its members possess many morphological and genetic characters in common. Тһе two above species have the same chromosome number and hy- bridize readily, hybridization occurring at times in nature. Seeds of both species were planted in the greenhouse October 25, 1938, and flowered from February to April, 1939, inclusive. Flowers and stems were given similar treatment throughout the eourse of the experiment. One per cent and .5 per cent lanolin pastes were prepared by dissolving the indoleacetie acid (Eastman & Mallinckrodt) in melted lanolin. They were then stored in dark bottles. Due to the instability of indole- acetic acid in water solution the method of Brannon (737) was followed, the auxin being dissolved in 95 per cent alcohol at a concentration of 4 mg./eec. The water solutions were prepared from this as needed. Тһе aleohol was redistilled to insure purity. Тар water was used in all tests. Water controls were run as checks on solution treatments and pure lanolin controls were used for comparison with the hormone-containing lanolin pastes. EXPERIMENTAL METHODS AND RESULTS RESPONSE OF FLOWERS TO INDOLEACETIC ACID Flowers were studied first as they present the most striking difference between the two species. Four parts of the corolla were recognized; (1) the slender constrieted portion of the tube to which the stamens are attached, herein called the tube, 1939] NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII 351 (2) the widened part of the tube, herein called the throat, (3) the gibbous ring of the throat, and (4) the limb (fig. 1). These Fig and b, external and internal strueture of Nicotiana alata flowers, e nis d, = N. Langsdor ffii · 1, tube; 2, throat; 3, gibbous ring of throat; 4, limb. parts show definite differences in cell structure and in growth rate. Direct and indirect methods of supplying additional hor- mone were used, the direct methods yielding the better results. [Vor. 26 352 ANNALS OF THE MISSOURI BOTANICAL GARDEN Lanolin paste was applied to the tube and throat of both spe- cies. In one series of tests one side was smeared with pure lano- lin as a control, and the other side with 1 per cent indoleacetic acid-lanolin paste, the two pastes not being permitted to touch. The calyx was cut away in both species to allow the paste to extend to the base of the tube. As a check, untreated flowers of the same size also had the calyx removed. Тһе corollas of N. alata ranged from 68 to 75 mm. in length at the time of treat- ment; those of N. Langsdorffii, from 13 to 17 mm. After the co- rollas were removed from the plant, a narrow strip from each treated side was measured. As indicated in table т and pl. 25, fig. 2, growth in N. alata was stimulated on the side receiving the hormone, a negative curva- ture of that side resulting within 48 hours. N. Langsdorffi showed no perceptible response (table п). If N. alata was treated when too mature, no curvature resulted; if too young, the side receiving the hormone became fluted and bulged, but growth in total length was inhibited. The throat showed only slight response or none. Untreated flowers which had only the calyx removed showed no curvature or other alteration. Growth was accelerated regardless of which side of the tube TABLE I EFFECT OF APPLICATION OF HORMONE PASTE AND PURE LANOLIN TO OPPOSITE SIDES OF N. ALATA COROLLAS Inerement of treated Length of tube side over untreated Side receiving Side receiving 1% pure lanolin indoleacetic acid- Length Percentage anolin paste mm, mm. mm. % 46 53 7 15,2 44 50 6 13.6 51 58 7 13.7 47 55 8 17.0 42 49 7 16.6 49 55 6 12.2 48 53 5 10.4 42 48 6 14.3 44 50 6 13.6 33 42 9 27.3 Av. 44.6 51.3 6.7 15.0 1939] NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII 303 received the hormone. Curvature resulted whether or not pure lanolin was applied to the side opposite the one treated with hormone. TABLE II COMPARISON OF TUBE LENGTH AFTER TREATMENT OF OPPOSITE SIDES WITH HORMONE PASTE AND PURE LANOLIN * Length of tube Side receiving Species Side receiving 1% indoleacetic of treated pure lanolin acid-lanolin side paste mm. mm. % N. alata 44.9 50.4 12.2 №. Langsdorffii 3.0 3.0 0.0 * Results are the average of 25 flowers each. Tn a second series of tests two corollas of the same size were selected and lanolin was applied all around the tube. Тһе con- trols received pure lanolin, the experimental flowers, 1 per cent indoleacetie acid-lanolin paste. In N. alata it was necessary to use two flowers from the same plant, as corolla-tubes maturing on a given parent at any time vary in length only two to five mm., whereas those from different parent stocks vary as much as 20 mm. (table іп). Тһе shorter the time elapsing between flower development, the less the variation on a given plant. The last flowers on a branch tended to be definitely smaller. In №. Langsdorffii the flowers varied so slightly that they could be taken from any plant. The calyx was again removed. Тһе size of the flower at the time of treatment was the same as in the preceding test. Results with N. alata were not as clearly defined as in unilateral treatment but nevertheless indicated the same sensitivity to auxin found in the first test (table ту). Very young flowers of N. alata did not give consistent results; those nearly mature did not respond at all. Difficulty arose in finding suitable pairs of flowers of this species. As before, the tube and throat of N. Langsdorfli showed no measurable re- sponse (table v), except a similar inhibition of growth with both treatments. [Vor. 26 354 ANNALS OF THE MISSOURI BOTANICAL GARDEN TABLE III VARIATION IN LENGTH OF UNTREATED N. ALATA COROLLA-TUBES Range of Plant no. Number of tubes variation measured per plant Longest | Shortest | Average mm. mm, mm. mm, 1 10 55 50 52.1 5 2 T 55 50 52.3 5 3 10 47 45 46.3 2 4 7 54 50 52.5 4 5 10 56 53 54.2 3 6 8 46 49 45.0 4 TABLE IV LENGTH OF COROLLA-TUBES AND THROATS OF N. ALATA TREATED ALL OUND THE TUBE WITH HORMONE PASTE 1% indoleacetic acid- Pair no. Pure lanolin control olin paste Tube Throat Tube Throat mm mm. mm. 1 45 95 47 95 2 58 23 55 23 3 51 22 54 24 4 53 23 55 23 5 53 24 54 24 6 48 24 55 24 7 49 27 54 29 8 42 30 47 30 9 39 20 39 24 10 52 23 55 Average 47.7 24.1 51.5 25.0 TABLE V LENGTH OF PAIRS OF COROLLA-TUBES LL TREATMENT ALL AROUND THE TU 1% indoleacetic Species Pure lanolin acid-lanolin paste Increase mm. mm. % А 47.6 51.5 8.2 №. Langsdor ffi 3.0 2.9 —3.0 * Results are averages from 25 flowers. Immature flowers were cut off and floated in a solution of 10 mg. indoleacetic acid per liter of water and measured after 48 hours. А comparable group was floated in water. N. alata 1939] NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII 355 corollas of various length were tried, but the only consistent results were that they seemed to mature more slowly than the water controls. In preliminary tests with У. Langsdorffii those corollas 17 to 19 mm. in length seemed to show definite increase in limb length and spread, also more blanching than average; a few plants normally showed this tendency. Repetition with two separate groups of fifty corollas each showed this increase in limb length to be consistent (table vr). The corollas had been sorted in pairs of equal size at the beginning of the experiment and one of each pair placed in hormone solution and one in water. If there was any variation in size, the water received the larger flower. TABLE VI LENGTHS OF pues OF COROLLA OF N. ss cages алеко: dii FLOATED HOURS IN HORMONE SOLUTI Treatment Limb | Tube and throat Total length Limb spread t mm. mm. mm. mm. 10 mg. indoleacetic acid Лет 5.0 23.1 28.1 15-17 Control 4.1 22.0 26.1 11-13 Vn largent UMS were мше. a Among the various indirect methods of supplying hormone to the flower was the application of lanolin paste to the stem be- low the inflorescence. When 1 per cent paste was used, there resulted an inhibition of flower buds above the treated area in N. alata, a slight inflation of the calyx being followed by yellow- ing and abscission. The growth of buds on older stems was not immediately checked, but the younger buds were affected. N. Langsdorffii showed definite local response such as stem eurvature, but this self-fertile species matured seeds as usual above the treated area unless the plants were given extremely heavy doses when very young. On either side of the stem below the inflorescence strips one- half inch in length were coated with the .5 per cent lanolin paste at three-day intervals. Not a sufficient number of plants of N. alata were treated to give conclusive results in a species [Vor. 26 356 ANNALS OF THE MISSOURI BOTANICAL GARDEN as variable as this. However, tube growth seemed to be some- what accelerated and the average length of the tubes was some- what greater than in the untreated flowers. Repeated applica- tions often led to an inhibition of growth above the treated area as with the more concentrated paste. Тһе frequent use of pure lanolin caused no change. Two branches of each of several plants were treated, one receiving the hormone, and one pure lanolin. After a time the former ceased to grow but the latter continued development, thus indicating that the hormone was very probably the cause of the inhibition. N. Langsdorffii showed no response to the .5 per cent lanolin paste except slight local curvature if application was uneven. Cut inflorescences of both species were placed in water solu- tion of indoleacetie acid and also in water. To be sure that re- sults were due to the hormone in solution and not to the alcohol which was used to dissolve it, equal amounts of alcohol were added to both. Neither showed any appreciable acceleration of flower size, but a concentration of 10 mg. per liter caused inhibi- tion of floral development in N. alata. Solutions of 5 mg. per liter or less resulted in neither bud inhibition nor noticeably larger flowers. The flowers of N. Langsdorffii were the same size in the water control and in the auxin solution. While both species keep well when eut, in hormone solution they seemed to keep longer than in water. In an effort to determine the source of growth substances, styles and stigmas were removed from the flowers of both spe- cies while they were still young. In N. Langsdorffii it is a sim- ple procedure to open the limb with fine forceps and to reach the style without damaging the corolla and stamens. Except with almost mature specimens of this species the flowers drop off before reaching maturity, usually within 24 to 48 hours after removal of the style. The younger the flowers, the sooner they drop off. The treated flowers were marked with blue on the calyx. Recent experimentation by Bonner and English (737, 738) has indicated the formation of the wound hormone, trau- matin, as a result of tissue damage. This could be a source of error, especially in N. alata, as it was impossible to reach the 1939] NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII 357 pistil with available instruments without damaging the corolla and stamens. Therefore, in some of the flowers the limb was cut away with a sharp razor. In half of these the stigma and part of the style were removed; in the other half they were left intaet. Even with the limb removed, it was difficult to reach the pistil. The cut inflorescences were then placed in water and covered with a bell jar to reduce transpiration. Previous ex- perience had shown that the flowers on cut inflorescences ma- tured satisfactorily in water. Those flowers with pistils re- moved tended to develop shorter tubes or to drop off, but some grew normally. On the plants, ten young corollas of various sizes were slit down one side of the tube and the style severed close to the base; others were slit, but the style left intact as controls. Both sets usually matured and the controls were then measured and examined for style injury. Again results were not consistent, but the flowers with severed styles tended to- ward shorter tubes; the throats were not greatly affected. Curvature toward the injured side developed in both. Normal cell structure and growth rate of the corolla parts were studied as an aid in understanding the reactions of these parts to indoleacetic acid. Two series of ten corollas of each species were marked off into tube, throat, gibbous ring of throat, and limb by means of fine blue lines. These parts were measured at 24-hour intervals until growth stopped. In L. Langsdorffii measurements of growth were started as soon as the corolla parts could be easily distinguished; in N. alata, when the corolla was approximately 35-45 mm. in length. Fig- ure 2 represents graphically measurements for the five days preceding full development in N. alata and the four days pre- ceding full development in №. Langsdorffit. Cell structure was not studied in detail, but a microscopic examination of the epidermal cells of the various parts was made in order to compare their size and shape. In N. alata the epidermal cells of the corolla-tube are extremely long and are similar to those of the Avena coleoptile in general shape (fig. 4A), whereas in N. Langsdorffii they are comparatively short, almost isodiametric (fig. 4B). As the growth rate of the THE MISSOURI BOTANICAL GARDEN [Vor. 26 358 ANNALS OF ку" декс те. pee soL ғ Қ . + , 4 Fe . «|. / + i 4 ч Ры 7 , aad a 4 "^ Nicotiana Langsdorffii Nicotiana alata / Tube о----5---- о---.-- MR Ahi L4 е d Throat iita dieses Не Gibbous ring of Р, Т пој ғы á ГА ры Limb Aie Aena M > ^ + зо |. E E "d E 8 . Е uL E = А 3 Pig 2 v id g 791 7 P d 7 T dl 4 д у > >= -Х P on Pw 15}. dt "i ех” Ld" LU Ser dali T е фени вата ет wt vL Ја ------” ла. 1 П а 1 Days Growth rates of corolla — of Nicotiana alata and №. Langsdor ffi. Fig. 2. Results are the means of 15 сого 1939] LANGSDORFFII 359 N. AND NAGEL—NICOTIANA ALATA tube of N. alata is very rapid and that of №. Langsdorffit very slow (fig. 3), a correlation between growth rate and cell elonga- tion is indieated. The cells of the throats of the two species are Growth Grow 4h --- = --..- 5” p d 1.-”---------- sol E ” Ри y! Жемнен < -- ^L б A ” 2” P d 4 Ж 7’ Anthesis з P М x - ў р У А я Sige зе 9? А". wt su Tr N. Langedorffii Я РАР Ж eo. off AT iod — 10 1 7 ~ К Doxs THROAT хы | p - T ------?” A ^ - Ем > - „> P д „> ~ : wh AP dg a . alata М. Lang sdorffis 3 == 1 А у Days Fig. 3. Growth rates of flowers used for each. - - - a хі LINB М. alata N. Копаздо а _____ 2}. Anthesis | 127 meee --- ---...... E айы 2.2297 анта т 4 pase seda eR RE е „ы „ NOU pe eorolla parts of Nicotiana alata Days GIBBOUS RING OF THROAT Ne slats. N Leng здо — | 3 2 5 Doys and М. Langsdorfhi. Three typical similar in size and shape (fig. 4E, F) and growth rate (fig. 3). They are shorter than those of the У. alata tube. In both species the cells of the gibbous ring of the throat show a grad- [Vor. 26 360 ANNALS OF THE MISSOURI BOTANICAL GARDEN ual transition from the longer ones of the throat to the iso- diametrie cells of the limb (fig. 4C). Тһе two species also have similar growth curves (fig. 3). Many stomata are present. = Sooo SOS SSS Hse Se - SSS Ss Ss Te ENTE c рлар аа Е SS БЕЗ СЫСЫ sss oS ue. re РЕА, % T H рр Se SS SSSI мя LLL ЁД —— ^ DERE DE Ep LL. ОЕР 2 А5555 E = 42 №: Fig еле pra s p “ға қ әдіс; E. Nicotiana alata and N. Mose Langsdorfii; C, gibbous ring of throat 2 x pre б pA xd. : саай tradi Hon from throat to limb); D, limb of N. alata; Сала D are similar in №. Langsdorffii; E, throat of N. alata; F, throat of N. Langsdorffit. While cells of the limb correspond very closely in the two spe- cies (fig. 4D), those of N. alata grow more rapidly, especially during the last few days of development (figs. 2-3). It is inter- esting that in N. alata the growth curve of the limb rises at 1939] NAGEL—NICOTIANA ALATA AND №. LANGSDORFFII 361 about the time of anthesis as the tube and throat curves flatten out. STEM RESPONSE TO INDOLEACETIC ACID A. peeuliar eurvature of the stem in N. alata, apparently resulting from the action of the hormone, suggested a limited study with stems of both species. Young flower stalks were used; old ones in which growth had practically stopped did not respond. If the primary stalk was used, it was cut off 45 to 60 em. from the tip; secondary ones were of necessity much shorter. These were placed in solutions of (a) 10 mg. of in- doleacetie acid/liter, (b) 5 mg./liter, (c) 1 mg./liter, and (d) tap water. Solutions were changed every other day until three or four treatments were given. Then the stems were placed in water which was changed as needed. With a concentration of 10 mg./liter, N. alata showed in- creased growth on the side opposite the insertion of the leaf in the younger parts of the stem and therefore marked curvature of the stem in the region of the upper leaves (fig. 5). This occurred in from two to five days from the beginning of treat- ment, the younger stems responding more quickly. At this concentration the flower buds which were nearly mature con- tinued normal development, while the younger buds turned yel- low and abseissed (pl. 26, fig. 2). With a concentration of 5 mg./liter, the stem curvature was slight and the flowers ma- tured in the same time as those of the controls (pl. 26, fig. 1). No effect was apparent with weaker solutions, nor with the small amount of alcohol used to dissolve the hormone, 21% се. per liter. While N. Langsdorffii also showed curvature with a concen- tration of 10 mg./liter, it was much less pronounced (pl. 26, fig. 2). The flower buds were not affected. Roots developed freely from the stem surface of N. alata in the region where indoleacetie acid solution had been applied. Both 5-mg. and 10-mg./liter solutions stimulated abundant root produetion. Stems also developed roots without treat- ment, but only near to the base, and they were not as numerous as on the treated stems. These results are in agreement with 362 ANNALS OF THE MISSOURI BOTANICAL GARDEN AVA ru {ў Fig. Nicotiana alata, showing curvature when stem was ый in a solution of 10 mg. indoleacetie acid/liter. Note that curvature is convex opposite insertion of leaf. [Vor. 1939] NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII 363 those of Stuart (737) and Pearse (738), who have found root development accelerated by auxin. According to Brase (737), failure to produce roots was not overcome in many species by use of synthetic growth substances. This seemed to be true of №. Langsdorffii, which did not produce roots either with or without treatment. As previously mentioned, applications of 1 per cent indolea- cetic acid-lanolin paste will induce local curvature of the stems in the treated region in both species. Even with one treatment, roots will finally break through the epidermis in N. alata. Inhi- bition of floral development above the treated area was com- plete, although branches below matured normally (pl. 26, fig. 3). N. Langsdorffii showed no inhibition and no root forma- tion, but matured its flowers and seeds normally in spite of extreme curvature (pl. 26, fig. 4). Growth was checked in this species only when high concentrations were used daily on young stems. External roots did not appear. A concentration of 0.5 per cent indoleacetic acid in lanolin produced the same type of result as the more concentrated paste, but to a less degree. N. alata showed gradual inhibition of growth above the treated area ; very few roots developed. Discussion The response of a plant to additional growth substance is conditioned by its sensitivity and its tendency to inactivate auxin. The curvature of the corolla-tube in N. alata following application of indoleacetic acid-lanolin paste indicates that this species has the ability to use additional hormone. This was also suggested by the increase in length of corolla-tubes follow- ing application of hormone paste all around the tube. Like the cells of the Avena coleoptile, the tube cells of N. alata respond readily to growth substance. Microscopic examination indi- cates that this increased growth in N. alata is the result of in- creased cell elongation rather than division. Cells of this type which in nature elongate rapidly are thought to be often capa- ble of using auxin for further elongation. The short tube cells of N. Langsdorffii show no response to hormone with any [Vor. 26 364 ANNALS OF THE MISSOURI BOTANICAL GARDEN method used. This indicates a probable inherent lack of ability to utilize growth substance, possibly due to lack of sensitivity to it or to its inactivation by oxidative destruction or enzyme activity. The difference in the tubes of the two species, not only in size but in cell structure and growth rate also, is probably due to the heritable genetic difference in the ability of their cells to respond to growth substance. The throats of the two species are similar in cell size and growth rate. In neither species did the throat show marked re- sponse to addition of growth substance. The limb of N. alata grew more rapidly than N. Langsdor fii during the last few days of development. Тһе development of the corollas floated in hormone solution possibly gives some insight into the effect of the hormone. Isolated corollas of N. alata, in which growth is normally very rapid, showed no increased growth over con- : trols, but both were considerably shorter than normal. Recent work of Alexander (738) and Stuart (738) has indicated that one of the effects of hormones such as indoleacetic acid in stim- ulating growth is the mustering of the food factor. N. alata normally grows with such rapidity that the food present in iso- lated corollas is probably soon exhausted and further growth then limited. N. Langsdorfii, which is comparatively un- responsive to indoleacetie acid in other parts of the corolla, shows increased growth of the limb when floated in hormone solution. This tendency was noted also after the application of lanolin paste, although exact measurements were not made. If auxin is considered to be one of the factors necessary for growth, it may be that not enough reaches the limb to allow optimum development and thus it becomes a limiting factor. Perhaps this explains why with direct application these cells are stimulated to increased growth. Since it is generally the terminal bud which produces hor- mone, the stigma and style, being considered the possible counterpart of the terminal bud, were removed to study the effect on the flower. That N. Langsdorffi flowers wilt and drop off after removal of these parts, unless nearly mature at the time, was considered as evidence that they may control the de- 1939] NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII 365 velopment of the flower in some way. Went and Thimann (737) make the general statement that auxin is one of the many fac- tors necessary for the ordinary growth process and that **with- out auxin, no growth." Absence of auxin may thus account for the laek of development. However, Avery and LaRue (738) have found that decapitated Avena coleoptiles will continue de- velopment on agar culture containing food and minerals for as much as six days after all measurable traces of growth sub- stance have been used up. 'The hormone is therefore probably not a necessity for growth although it does stimulate or ‘‘cata- lyze’’ it. On the other hand, №. alata flowers are often devel- oped after the removal of the stigma and part of the style, although with shorter tubes than usual. Growth is limited, but not often stopped. This may be due to inhibition caused by the wound hormone, traumatin, or it may be that some other source supplies the growth substance. It is also possible that all of the long style was not removed and that there is a “тесепегаһоп of a physiological tip’’; or that the part of the style remaining still produces enough auxin for limited growth. А study of the flowers of the two species seems to indicate that their differences lie in genetic differences in response to hormone, N. alata being sensitive to it, N. Langsdorffii lacking in ability to use it or inactivating it. When eut young flower stalks were placed in hormone solu- tion, the ‘‘unphysiologically’’ high concentration of indoleace- tie acid—10 mg./liter—was carried upward in the transpira- tion stream (Hitchcock and Zimmerman, 735). This is not in opposition to the usual concept of polarity expressed by Went and Thimann (737). The curvature of the young stems was brought about by greater growth on the side opposite the leaves. Тһе lessened growth in the region of the leaf insertion may have been caused by a lower concentration of hormone in the stem owing to its passage into the leaf. Old stems show no curvature because the aging of the cells renders them unre- sponsive. Ж. alata, with characteristic sensitivity and good transport facilities, curved strongly, the degree of curvature depending upon age of the cells and concentration of the hor- [Vor. 26 366 ANNALS OF THE MISSOURI BOTANICAL GARDEN mone. In the cut stems of №. Langsdorffii the hormone was probably likewise carried upward in the transpiration stream, but the resulting slight curvature showed little use of the addi- tional hormone. It is possibly significant that the total height of N. alata is greater, 150 to 190 cm., than of N. Langsdor ffi, 110 to 120 em. Both species respond to local application of 1 per cent indoleacetic acid-lanolin paste in young stem regions. As this is also an ‘‘unphysiologically’’ high concentration of hormone, unequal application of it stimulates N. Langsdor ји locally to marked curvature but no roots appear. Due to the destruetion of the hormone in transport or to laek of sensi- tivity of this plant to it, the flowers and other parts were not affected. N. alata showed similar local eurvature of the stem with formation of adventitious roots. The effects from both lanolin application and solution treat- ment are not limited to the stems of N. alata, but are extended to the flower stalk. With the concentrations used, growth was completely inhibited and flower buds and upper nodes of the flower stalk were eventually killed. This again seems to indi- cate that inactivation does not occur in N. alata, as a high con- centration of the substance apparently reaches the flowers. Because of the great sensitivity of the cells of N. alata to hormone, the concentrations used proved to be toxic to the younger cells. That very young corollas do not respond favor- ably to applications of lanolin paste might be explained by this fact. The upper tissue is perhaps partly inactivated by the mobilization of food materials in the treated area of N. alata as this region responds with the formation of numerous roots; and development of roots requires food material. The differentiation of the tissue to form roots on the stem would possibly interfere mechanically with transport and aid in causing inhibition above the region of application. Cut flower stalks of М. alata produced some basal roots without any treatment, but more if treated with 5 or 10 mg. indoleacetie acid/liter. N. Langsdorffii, however, produces none under such conditions, thus giving additional evidence that N. alata prob- ably is hereditably more able to use growth substance. As is 1939] NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII 367 usually true, N. alata roots more quickly when treated. It has been suggested by Went (738, '39) and Cooper (738) that indoleacetie acid stimulates rooting by causing a redistribu- tion and then an activation of the rhizocaulin already present in the tissue. Went and Thimann (37), in the light of the work of Lehman, Hinderer, Schlenker, and others, on Epilobium hybrids, sug- gest that possibly the sensitivity to growth hormone might be determined by the genes; the auxin production, by the cyto- plasm. Тһе above results suggest that morphogenetie differ- ences in hormone response probably account for the principal differences between the two species studied. SuMMARY 1. The corollas and flower stalks of Nicotiana alata and Langsdorffii were used in studying the role of growth hor- mones in morphogenesis. 2. The corollas were found to serve as especially favorable material since they follow the same general growth pattern, but differ markedly in cell elongation. Results indicate that N. alata generally has greater ability to use additional hor- mone than №. Langsdorffii. The former also is more sensitive and smaller amounts prove toxic to young cells. Corollas of N. Langsdorffii give evidence of inactivation of growth hor- mone except in the limb. 3. Young flower stalks inserted in hormone solution respond by curvature on the side opposite the leaf insertion. The re- sponse is much greater in Ж. alata than in №. Langsdorffii, and in both species depends upon the age of the stem and the con- centration of the hormone. 4. Experiments indicate that many of the principal differ- ences between the two species lie in a genetically controlled difference in their ability to use hormone. I wish to take this opportunity to express my appreciation to Dr. Edgar Anderson, of the Henry Shaw School of Botany, for suggesting the problem and for the use of the greenhouse and materials; to Dr. George T. Moore, Director of the Mis- [Vor. 26, 1939] 368 ANNALS OF THE MISSOURI BOTANICAL GARDEN souri Botanieal Garden, for the use of the library; to Dr. Edna L. Johnson, of the University of Colorado, for her as- sistance and encouragement in this problem, submitted as partial fulfillment of the requirements for the degree of Master of Arts at the University of Colorado. LITERATURE CITED Alexander, Taylor R. (’38). Carbohydrates of bean plants after treatment with indole—3—acetie acid. Plant Physiol. 13: 845-858. Avary, George S., Jr., and Carl D. La Rue Sade Growth and tropie responses of cised шы coleoptiles. Bot. Gaz. 1 186-200. Јо "Priscilla pa: ). корана evidences ‘of Nicotiana phylesis in the alata- group. Univ. Calif. Publ. Bot. 18: 153-194. Bonner, James, һөй Әатев English, Jr. (738). A chemical and Ars at. study of traumatin, a plant wound hormone. Plant Physiol. 18: 331 Brannon, M. A. (737). Algae and growth-substances. Science N.S. " 353-354. Brase, Karl D. Сат). кыш growth substanees in the sida of soft wood wisi) of deciduous fruits. Amer. Soe. Hort. Sei. Proe. 35: 431-437. (Ab- et) Кың W C. (738). Hormones and root formation. Bot. Gaz. 99: 599-614. English, J., Jr., and J. Bonner (737). The wound hormones of pn I. Trauma- tin, the active prineiple 3 the bean test. Jour. Biol. Chem. 121: 791-799. Hitchcock, A. E., and P. W. Zimmerman (735). Absorption and = of synthetie growth substances from soil as indieated by the responses of aerial parts. Boyee Thompson Inst. Contr. 7: 447—476. Pearse, Н. L. (738). Experiments with growth-controlling substances. I. Th reaction of leafless woody cuttings to treatment with root-forming substances. ot. N.S. 2: —235. ви. ‘Neil W. (’38). Nitrogen and carbohydrate metabolism of kidney bean cuttings as affected by treatment with indoleacetie acid. Bot. Gaz. 100: 298- and Paul C. Marth (787). Composition and rooting of American holly eiiim as affected by treatment with indolebutyrie acid. Amer. Soc. Hort. Sei. Proe. 35: 839—844 Van Overbeek, J. (735). The growth hormone and the dwarf type of growth in corn. Nat. Acad. Sei. Proc. 21: 292-299, , (738). Auxin production in seedlings of dwarf maize. Plant Physiol. 13: 587—598. Went, F. W. (738). a factors other than auxin affecting growth and root formation. —* и e di effect of auxin on root formation, Amer, Jour. Bot. 26: 24-99. ‚апа Kenneth V. Thimann (787). Phytohormones. Macmillan, New York. [Vor. 26, 1939] 310 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 25 Fig. 1. At left, inflorescence of Nicotiana alata; at right, inflorescence of Nicotiana Langsdorffii. Fig. 2. Curvature of Nicotiana alata in response to treatment with 1 per cent indoleacetie acid-lanolin paste. In flower at left, right side of tube had been treated with hormone paste; left side with pure lanolin. Flower at right was untreated. ANN. Mo. Вот. GARD., VoL. 26, 1939 PLATE 25 NAGEL—NICOTIANA ALATA AND N. LANGSDORFFII [Vor. 26, 1939] 312 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 26 Stems of Nicotiana alata which were placed in a solution of indole- ig. 2. Stems of Nicotiana kept in a solution of 10 mg. йел acid/liter for four days. Left, N. Эт” right, N. alata. Note greater bud inhibition and stem curvature in N. ala Fig. 3. Nicotiana alata va. treated with 1 per cent indoleacetie acid-lanolin paste. Note the inhibition of growth and abseission of buds above the treated area. The white spots in the treated area are roots. Fig. 4. Nicotiana Langsdorfii stem showing curvature which followed treat- ment with 1 per eent indoleacetie acid-lanolin paste. Floral development is not checked and seeds mature as usual above the treated area. ANN. Mo. Вот. GARD., VOL. 26, 1939 PLATE 26 2 1 NAGEL—NICOTIANA ALATA AND L. LANGSDORFFII MONOGRAPH OF THE NORTH AMERICAN SPECIES OF THE GENUS EPHEDRA’ HUGH CARSON CUTLER Formerly VanBlarcom end in the Henry Shaw School of Botany of ashington University INTRODUCTION The importance of the drug, ephedrine, secured from Asiatic species of Ephedra, in the treatment of nasal colds, asthma and hay fever has attracted wide attention to this genus. Workers in range management have investigated the relative palatability of various species, and students of phylogeny have speculated on the role of the genus in a phylogenetic sequence. These last have contributed to the confusion in the terminology for, in addition to applying descriptive terms derived from Angiosperm and Gymnosperm sources, they coined new ones. Unfortunately, many of the investigations are of little value because the material was incorrectly identified or was a mix- ture of more than one species. Correct determination of material is extremely difficult, for the number of species has nearly doubled since the publication of the last monograph of the entire genus and many of them were originally described from sterile or from staminate ma- terial. Approximately two-thirds of collected specimens can- not be identified with certainty from existing descriptions. The present study determines the correct application of names, proposes several new ones for hitherto undescribed forms, de- limits the North American species, and provides means for their accurate determination. The South American species are not discussed in the present work but will be taken up later. Manuals, floras, and other works which recognize species of 1 An investigation carried out at the Missouri Botanical Garden in the Graduate Laboratory of the Henry Shaw School of Botany of Washington University and submitted as a thesis in partial fulfillment of the requirements for the degree of doctor of philosophy in the Henry Shaw School of Botany of Washington University. Issued November 30, 1939. ANN. Mo. Bor. GARD., Vol. 26, 1939 (373) [Vor. 26 314 ANNALS OF THE MISSOURI BOTANICAL GARDEN Ephedra are not cited in the text of this paper unless they are necessary for bibliographieal reasons. Such citations might indicate acceptance of the entities as delimited in those works, which is usually not the case. Тһе more important publica- tions may be found in the history, generie and specific syn- onymy, and bibliography. History Ephedra has been known and used medicinally in China for about five centuries. Its general acceptance by Western phar- macists is comparatively recent. Groff and Clark? summarize the history of its use in medicine and indicate the scant value many analyses have because the material upon which they are based is not definitely determined. To be serviceable, analyses of the plants should be accompanied by the name of the species and the location of herbarium material, the locality in which it grew, the date of collection, the parts of the plant analyzed, and the methods of drying, of extraction and of measurement. The genus Ephedra was definitely established by Linnaeus in the ‘Species Plantarum’? and in the ‘Genera Plantarum’! of 1753 and 1754 respectively. Two species, E. distachya and E. monostachya, were included by him in the former publica- tion. The first North American species to be described was Е. antisyphilitica in C. А. Meyer’s® monograph of the entire genus. In 1848 Torrey® recorded another species as ‘‘ Ephedra occidentalis" which was later validly published by Watson? as Е. trifurca. Watson’? described three species, E. californica, E. nevadensis, and E. Torreyana, in 1879; and four years later? published E. aspera and E. pedunculata from the notes of Engelmann. The second and latest monograph of the genus * Groff & Clark in Univ. Calif. Pub. Bot. 14: 247-282, charts 1-6. 1928. 31,, Sp. Pl. 2: 1040. 1753. + L., Gen. Pl, ed. 5, 462. 1754, ы Мече; С, А, in Mém. Асай. Imp. Sci. St. pur VI, Sei. Nat. 5: 291. 1846, * Torr. in Emory, Mil. Бесопп, 151. 184 * Wats. іп U. В. Geol. Surv. rhea Part | Bot. King's Exp.] 5: 329. 1871. * Wats. in Proc. Am. Acad. 14: * Wats. in Proc. Am. Асай, 18: Dr "a. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 315 appeared in 1889, and in it Stapf!? published two subvarieties of E. nevadensis, subvar. paucibracteata which is synonymous with the species, and subvar. pluribracteata which is a syno- nym of E. viridis Coville! published in 1893. In 1909 the most southern of the North American species, E. compacta, was de- scribed by Rose.!2 Johnston'? in 1922, and Соғу! in 1938, de- scribed E. peninsularis and E. Reedii respectively, both of which are synonyms for E. aspera. Groff and Clark?* pub- lished a survey of the North American species in 1928 as an aid to the study of the drugs contained in plants of the genus. Nelson'* described E. fasciculata from vegetative material in 1935, and in the same year Coville and Morton!* proposed Е. funerea, and Reed!’ Е. texana, which is synonymous with E. antisyphilitica. E. Coryi Reed!? was published in 1936, and in 1938 E. Reedii Cory and E. antisyphilitica var. brachycarpa Cory?? appeared. GENERAL MORPHOLOGY The North American members of the genus are, with the ex- ception of the clambering E. pedunculata, erect woody shrubs. All species have reduced scale-like leaves and photosynthetic young stems. Seedlings—The tap-root of the young seedlings soon branches to form a fibrous root system with numerous root hairs and a diarch or occasionally triarch stele. Two cotyle- dons are produced. The first leaves of all species are borne in pairs, and the ternately leaved forms show the whorled ar- rangement only after several pairs have been produced. In Е. ? Stapf in Denksehr. К. Akad. Wiss. Wien 56°: 1-112, pls. 1-6, 1 тар. 1889. " Coville in Contrib. U. S. Nat. Herb. 4: 220. 1893 12 Rose in Contrib. U. S. Nat. Herb. 12: 261. 1909. із Johnston in Univ. Calif. Pub. Bot. 7: 437. 1922. ^ Cory in Rhodora 40: 216. 1938. 15 Groff & Clark in Univ. Calif, Pub. Bot. 14: 247-282, charts 1-6. 1928. 16 Nelson in Am. Jour. Bot. 21: 573. 1935. и Coville & Morton in Jour. Wash. Acad. Sci. 25: 307. 1935. з Reed in Bull. Torr. Bot. Club 62: 43. 1935. ? Reed in Bull. Torr. Bot. Club 63: 351, figs. 1-2. 1936. * Cory in Rhodora 40: 218. 1938. [Vor. 26 316 ANNALS OF THE MISSOURI BOTANICAL GARDEN Torreyana the endosperm remains attached to the base of the stem by means of а foot, although Voth?! indicates that Ephedra is the only Gnetalean genus lacking this organ. From 420 seeds of E. trifurca, E. Torreyana, E. antisyphi- litica, E. aspera, E. Coryi var. viscida and E. viridis, in about equal numbers gathered in May and June and planted in Sep- tember, only eleven seedlings were obtained, nine of E. Torrey- ana and one each of E. trifurca and E. Coryi var. viscida. No seedlings and only a very few young plants were observed during two seasons of field work, and it is probable that the most frequent type of propagation is by means of divisions of buried stems. It has been suggested that the peridermal dia- phragm at the base of each internode which allows the stems to fragment readily is a device to aid propagation by the rooting of the segments. It is highly improbable that many of these seg- ments would root under the xerophytie conditions character- istie of the habitat of Ephedra. Stem.—The green stem is solid, furrowed, and usually roughened by the cutinized and thickened epidermal walls which contain calcium oxalate. Blunt papillae occur on the thickened walls, and the size and number of these determine the degree of asperity of the stem. While the papillae vary greatly within a species, the width of the furrows and ridges and the number of stomata per unit of area remain nearly con- stant. The epidermal cells upon the ridges are longer than those in the furrows and are underlain by a bundle of hypo- dermal fibers. In most species the stomata are confined to the furrows and usually are sunken, although in E. antisyphilitica, E. com- pacta and E. pedunculata the striation is not extensive and the stomata are scattered over the entire surface. The stomatal pits are prominent in these three species, especially in E. com- pacta. The size and shape of the stomata vary with the species. Stomatal frequencies are relatively constant for each species, provided stems of the same age and from plants in almost similar habitats are examined. While it would be bet- = Voth in Bot. Gaz. 96: 298. 1934. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 377 ter to use the stomatal index (I = x 100, where s is the fre- e-s quency of stomata and e the frequency of epidermal cells in the same unit area) selection of the material to be examined makes it possible to secure figures subject to only slightly greater variation. The cells on the edges of the ridges are difficult to see without special preparation, but Pont?? in studies on two species of plants did not count the epidermal cells upon the ridges. Frequently, however, it is difficult to distinguish be- tween the cells of the furrows and those of the edges of the ridges, although the latter are usually longer. By utilizing supplementary characters such as those just mentioned it is possible to identify almost any specimen of Ephedra from North America. Table 1 lists figures which will aid in the determination of vegetative as well as staminate and ovulate material. The outer layers of cortical cells are chlorophyll-bearing and include numerous air spaces. Starch grains, calcium oxalate erystals and tannin are enclosed within many of these cells. Three systems of fibers are distinguished in this region by Graham??: the hypodermal, which underlies the ridges, as hitherto mentioned; the mesocortical, which is scattered through the cortex; and the pericyclic, which is scattered about on the periphery of the stele with the largest fibers abutting the vascular strands. The hypodermal fibers and those of the pericycle which adjoin the vascular bundles are the most con- stant in numbers and in size. At the nodes this fiber system is interrupted. Lignified cells and fibers are found in the pith, and a peri- dermal diaphragm is produced at the base of each internode, which, with the interruption of the fiber system, allows ready fragmentation of the stems. The stele is an endarch siphonostele with a slight variation in the numbers of bundles. Those species characterized by ternate arrangement of the leaves and bracts have three pairs 2 Pont in Већ. z. Bot. Centr. 59: 214—224, 6 figs. 193 2 Graham in Trans. Roy. бос. Edinb. 46: 203-212, 3 3. 1909. 378 TABLE I COMPARISON OF NORTH AMERICAN EPHEDRAS ANNALS OF THE MISSOURI BOTANICAL GARDEN олоца -олоцјив uo [Vor. 26 81 о ђе о о Ф о со |t-t- © © | > -ug jo лодшти [ens[) juosqu 10 МР У ЧЕ 403 un . ы ы ыны ы ы quosord 80140248 cicicli-riciricic AAA & R ав e6jv[nAO јо o[pounpoq нінен ку УУ oit vi on t сї сї сч сї т ri са ur врәәв jo лодштмј = == === Аце up Tem , ; с адыш а qd : Qu mowuw | 558855456 fid $ d 44 вподовивлашо СНЕНЕЕНЯЕНЕЗ 26 28 = j?€"1q oj9[nA() E . са oo e шш “bs 194 25852528552 боб Q о Efa вуешодв ЈО i1equinN pum вр P. vibe Ди“ д "а“ mon ME в ш вәә zo 10quinN spuers 1oqy [eur осоозсосососо соз с c сл оо сон со О OD SH XH IO LD too со со са are -ләройАц jo лэашам | | му | мо саму о oo © 01938 е ur So[punq и ааа оччо о on Iv[no88A Jo лодштим 2 плана ob ob ab © вәәлдәр є о об из <> 19 1M 1 © и сї со са oo oo eo ооцоЯлелтр Yyouvsq © че О і оосо BHA A + со мо әјдив одвлолу со тоқа wv wp Буна eo со со | 69 ео өз 03 01 63 саса сч e са сч сї сч 10 волвој JO лодшим wod ur epouiejur | очи оо „из о «аєа - v " jo ibd әЗеләлұ с5 сї ci о «сб сз сї сб са са сї са се са сз 3 1 э ce 3 * л eZ + 3535 8 $c 8 S ® ss E S ‚> AS РЕЗЕ ES ы & 8,53 ъф © +41 SS Sua m > зава ЕО ЕТО Fr Ses ES .S8 FS 8 55552; geet тыны eS uds РУЕДА харх ммм vii ә Рени нсі4Чашыбсе6 ded < 8 wes v у "ч e гч = rei "= 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 379 or three groups of three small bundles. In forms with binate arrangement of parts the vascular system consists of two pairs of large bundles alternating with two pairs or with three groups of three small bundles. The xylem consists of spiral primary elements and second- ary tracheids and vessels with bordered pits. These last are modified tracheids, and the oblique end walls have bordered pits larger than those on the lateral walls. These pits enlarge to lose both torus and border and occasionally fuse.?* The primary phloem consists of cambiform parenchyma ele- ments and narrow sieve-tubes with oblique plates. Тһе wood rays are large, uniseriate in young wood, multi- seriate in older branches, and consist of storage parenchyma and transformed longitudinal fibers. Тһе pits are small and simple. Depressions in the wood correspond to the positions of thelarge rays. There is no apparent relation between the posi- tion of the rays and that of the leaf traces. Тһе angle formed by the branches with the stem in any species is relatively constant, although the amount of branch- ing and the length of branches and of internodes are variable within limits for each species and are altered by changes in environmental conditions. Leaves.—The leaves are small, scale-like, and usually con- nate. The median and basal portions are thickened, and an abscission layer developed near the base renders the leaf caducous in most species. The leaves are either opposite or ternate and the whorls alternate. Strobili.—All the North American species are essentially dioecious, but it is often possible to find a plant of any species which bears strobili of both types. I have also seen bisporangi- ate strobili on otherwise staminate plants of E. trifurca, E. Torreyana, E. aspera and E. Clokeyi. Bisporangiate strobili were not found on ovulate plants. Apparent sexual differenti- ation is confined to the peduncles and strobili. Тһе staminate strobili are compound and borne in pairs or * Jeffrey, The anatomy of woody plants, p. 367. 1917. [Vor. 26 380 ANNALS OF THE MISSOURI BOTANICAL GARDEN whorls at the nodes of the young branches, or rarely terminally. They consist of an axis bearing 2-13 whorls of binately or ter- nately arranged braets, all except the lower subtending a vasi- form perianth which surrounds a staminal column. Upon this eolumn, or sporangiophore, are borne the three to twelve usu- ally bilocular anthers which may be sessile or stipitate. The column in some species is very variable. In E. Clokeyi it may attain a length three times the normal, and in E. Torreyana a slender column may bear one uniloculate anther or a branched column may bear up to ten bi- and triloculate anthers. The bract and perianth are more constant in size within the species, and outlines of these and typical columns are figured in plate 27. The ovulate strobili are solitary or whorled at the nodes of the young branches and may be sessile or long-pedunculate. Three to twenty whorls of membranaceous to fleshy bracts sur- round the one to four ovules. The ovule is enclosed by two integuments, the inner extending through an opening of the outer to form a tubillus which leads to the pollen chamber at the tip of the ovule. Although the form of the tubillus was used as a character in the delimitation of species by both Meyer and Stapf, it varies somewhat in most of the American species and is not of great value as a diagnostic character. The length of the peduncle, the number, shape, size and texture of the bracts, and the character and numbers of seeds (pl. 27) are the most valuable characters in delimitation of species. PHYLOGENY AND GEOGRAPHICAL DISTRIBUTION It is possible to trace a probable course of evolutionary de- velopment among the American species of Ephedra, but such speculation is of little value unless based upon a thorough knowledge of the entire genus. The apparent differences be- tween species of even separate continents are often so slight that all must be considered in any theorizing upon develop- mental sequences. The key to the species is artificial, and the entities are grouped only so that the most similar ones are close together. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 381 The distribution maps (pl. 28) are fairly aecurate with the exception of Nevada and Mexico, where an insufficient number of collections have been made. The region of greatest specific concentration for North America is in west-central Arizona where seven of the eighteen entities occur. ACKNOWLEDGMENTS The author is deeply indebted to numerous people whose aid and advice have made the present study possible. For the privileges of studying at the Missouri Botanieal Garden and the use of the herbarium and the library the writer expresses his thanks to Dr. G. T. Moore, Director of that institution. Grateful acknowledgment is also due Dr. J. M. Greenman, Curator of the Herbarium, and Miss Nell C. Horner, Librarian and Editor of Publications. Entire or partial collections of Ephedra were borrowed from several institutional and private herbaria, and certain herbaria were visited. То these institutions and individuals the author wishes to express his gratitude. These herbaria are indicated in the text by the following abbreviations: (BYU) —Brigham Young University. (Buf) —Buffalo Museum of Science. (CA) — California Academy of Sciences. (Clo) —Herbarium of I. W. Clokey. (F) —Field Museum of Natural History. (G) —Gray Herbarium of Harvard University. (I) —Iowa State College. (M) —Missouri Botanical Garden. (NMAM)—New Mexico State College of Agriculture and Me- chanie Arts. (P) —Pomona College. (R) —Rocky Mountain Herbarium of the University of Wyoming. (S) —Leland Stanford University. (SD) --бап Diego Natural History Museum. (T) —Agricultural and Mechanical College of Texas. [Уог. 26 382 ANNALS OF THE MISSOURI BOTANICAL GARDEN (TTC) —Texas Technological College. (UC) —University of California. (UI) —University of Iowa. (UNM) —University of New Mexico. (UW) = —University of Wisconsin. (US) —United States National Herbarium. TAXONOMY Ephedra [Tourn.] L., Sp. Pl. 2: 1040. 1753; Gen. РІ., ed. 5, 462. 1754; C. A. Meyer in Mem. Aead. Imp. Sei. St. Petersburg, VI, Sci. Nat. 5: 291. 1846; Endlicher, Syn. Conif. 253. 1847; Torr. in Emory, Mil. Reconn. 151. 1848; Torr. in Emory, Rep. U. S. & Mex. Bound. Surv. 2: 207. 1859; Parl. in DC., Prodr. 16?: 352. 1868; Wats. in U. S. Geol. Surv. Fortieth Parallel [Bot. King's Exp.] 5: 328. 1871; Parry in Am. Nat. 9: 351. 1875; Wats. іп Proc. Am. Acad. 14: 298. 1879; Wats., Bot. Geol. Surv. Calif. 2: 108. 1880; Wats. in Proc. Am. Acad. 18: 157. 1883; Stapf in Denkschr. K. Akad. Wiss. Wien 56?: 1. 1889; Coult. in Contrib. U. S. Nat. Herb. 2: 552. 1894; Rydb. in Colo. Agr. Exp. Sta. Bull. [Fl. Colo.] 100: 10. 1906; Rose in Contrib. U. S. Nat. Herb. 12: 261. 1909; Coult. & Nels., Man. Rky. Mt. Bot. 19. 1909; Jepson, Fl. Calif. 65. 1912; Wooton & Standl. in Contrib. U. S. Nat. Herb. 19: 38. 1915; Goldman in Contrib. U. S. Nat. Herb. 16: 315. 1916; Rydb., Fl. Rky. Mts. and Adj. Plains, ed. 1, 19. 1918, ed. 2, 19. 1923; Standl. in Contrib. U. S. Nat. Herb. 23: 63. 1920; Johnston in Univ. Calif. Pub. Bot. 7: 437. 1922; Abrams, Ill. Fl. Рас. States, 77. 1923; Davidson & Moxley, Fl. So. Calif. 31. 1923; Jepson, Man. Е. РІ. Calif. 61. 1925; Tidest. in Contrib. U. S. Nat. Herb. 25: 56. 1925; Rehder, Man. Cult. Trees & Shrubs, 67. 1927; Groff & Clark in Univ. Calif. Pub. Bot. 14: 247. 1928; George, Supp. aux Mém. бос. Sei. Naney 1930: 29. 1930; Coville & Morton in Jour. Wash. Aead. Sei. 25: 307. 1935; Jepson, Man. So. Calif. Bot. 19. 1935; Nelson in Am. Jour. Bot. 21: 573. 1935; Reed in Bull. Torr. Bot. Club 62: 43. 1935; Reed in Bull. Torr. Bot. Club 63: 351. 1936; Cory in Rhodora 40: 216. 1938. Chaetocladus Senilis [=Nelson] Pinac. 161. 1866. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 383 Erect or clambering, dioecious or rarely monoecious shrubs ; branches equisetoid, solitary, or whorled; vascular cylinder an endarch siphonostele; wood rays large, uniseriate in young wood, multiseriate in older branches, composed of storage parenchyma and transformed longitudinal wood fibers; wood containing vessels with oblique terminal walls perforated by numerous pits larger than those on lateral walls, the mem- branes of these terminal pits lost at an early stage, the pits oc- casionally fused to form slits; leaves binate or ternate, small, usually united to form a sheath; staminate strobili compound, binately or ternately whorled bracts including a vasiform structure composed of the base of the antherophore upon which are borne the few to many usually biloculate sessile to short-stipitate anthers; ovulate strobili with few to many whorls of binately or ternately arranged membranaceous to fleshy braets surrounding the one to several ovules, the inner integument extended to form a cylindrical projecting tubillus ; two archegonia usually present. Type species: Ephedra distachya L., Sp. Pl. 2: 1040. 1753. ARTIFICIAL KEY А. Leaves and bracts of spikes ternate. B. Leaves becoming shredded and gray with age, persistent; terminal buds spinose. C. Leaves more than 8 mm. 1010:.:,.425.:5.5.22....%...... 1. E. trifurca CC. Leaves less than 8 mm. Іопр.......................... . E. intermizta BB. Leaves remaining firm or falling off with age; terminal d not spinose. D. Seeds less than one-half as wide as long, cream to light brown, rough and angular. E. Ovulate braets as broad as long or broader; east of California.. а КК СҮТ iro NEA UE Пе ein «4 3. E. Torreyana EE. Ovulate braets two-thirds as broad as long or less; Death Valley region to Nevada.........- иШ ие. oles segs 5. E. funerea DD. Seeds more than one-half as wide as long, brown, smooth and almost spherical... о с: сасе ва соо ER eee seas vs ве 6. E. californica AA. Leaves and bracts of spikes binate, occasionally terna F. Inner braets of the ovulate Api membranaceous or ИЕК ТЕ б. Seeds solitary, ог if more than on era in eolor. H. Seeds almost нат in eross-sectio I. Seeds smooth, brown to chestnut in бе leaf-bases brown T per- sistent; stem usually rough, о.е ене. . E. aspera [Vor. 26 384 ANNALS OF THE MISSOURI BOTANICAL GARDEN II. Seeds furrowed or seabrous, light brown to gray-green; leaf-bases gray and deciduous; stem usually almost smooth. J. Seeds more than 9 mm. lon ЗИМИ EEA $. E. fasciculata JJ. Reeds Tees than 9 mo. ЮӘб..».............22:2%... 9. E. Clokeyi HH. Seeds trigonal or tetragonal in cross-section.......... 4. E. arenicola GG. Seeds paired, brown to almost blac K. Ovulate spikes sessile or very P — seeds Ser fur- rowed longitudinally; leaf-bases brown................ E. viridis KK. Ovulate spikes usually long- ны. ; seeds usually gius leaf-bases gray or brown . Leaf-bases deciduous and gray; seeds about one-half as thick as long; stem not viseid. M. Seeds more in 5 mm. in length, slightly exserted, chestnut ; bracts with a faint trace of pink.............. 10. E. nevadensis MM. Seeds 5 mm. or less in length, almost included, nearly black; bracts bright pink to rose............ 10а. E. nevadensis f. rosea LL. Leaf-bases persistent and brown; seeds less than one-half as thick as long; stem viscid.............. 12a. E. Coryi var. viscida FF. Inner bracts of the ovulate spike becoming fleshy; eastern Mexico and United States east of Central New Mexico. N. Seeds solitary O. Seed never less than 6 mm. long, less than 3 mm. broad, slightly nue T ЖИК КААК ГҮ ҮК КГУ TI E E. antisyphilitica OO. Seed less than 6 mm. long, — 3 mm. broad, include оса клони чи КЕ а ага ње . E. Деи var. brachycarpa NN. Seeds paired. . Braets red; leaf-bases gray and deciduous. Q. Low compaet ега not elambering; ovulate spikes sessile; anthers not kno E E TITIUS. 14. E. compacta QQ. Clambering она, ovulate spikes peduneulate; anthers long- xm amne ВИСТА. И У ум 15. E. pedunculata 1. Ephedra trifurca Torr. ex Wats. in U. S. Geol. Surv. For- tieth Parallel [Bot. King's Exp.] 5: 329. 1871. E. occidentalis Torr. in Emory, Mil. Reconn. 151. 1848 [in error, evidently intended for E. americana Willd. }. Е. trifurcus Torr. in Emory, МИ. Reconn. 152. 1848. E. antisyphilitica Torr. in Emory, Rep. U. S. Mex. Bound. Surv. 2: 207. 1859, in part. E. trifaria Parl. in DC., Prodr. 162: 359. 1868. Erect dioecious shrub, 0.5-2 m. high; branches rigid, hard, terete, up to 3.5 mm. thick, solitary or whorled at the nodes, angle of divergence with the main stem about 30 degrees ; inter- 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 385 nodes 3-9 em. long; bark of young stems pale green, almost smooth, with numerous small longitudinal furrows, becoming yellow, then gray-green ; bark of older stems cinereous, cracked and somewhat irregularly fissured longitudinally; terminal buds 1 em. long, spinose; leaves ternately whorled, 5-13 mm. long, subspinosely tipped from a dorso-median thickening, con- nate for one-half to three-fourths their total length; sheath at first membranaceous, later fibrous, shredded and grayish, per- sistent; staminate spikes solitary or numerous in a whorl at the nodes of the young branches, obovate, 6-9 mm. long, short- pedunculate, peduncles many-scaled, bracts ternate, in 8-12 whorls, obovate, slightly clawed, 3-4 mm. long, 2-3 mm. broad, membranaceous, reddish-brown, the lower whorls empty; perianth almost equaling the subtending bract; staminal column 4-5 mm. long, one-fourth exserted, with 4-5 short- stipitate anthers; ovulate spikes solitary or numerous in a whorl at the nodes of the young branches, obovate, 10-14 mm. long, short- and scaly-pedunculate or sessile, bracts ternate, in 6-9 whorls, orbicular, clawed, 8-12 mm. long, 9-12 mm. broad, translucent except for the reddish-brown center and basal por- tion, margins entire; fruit solitary or, occasionally, two or three, usually tetragonal, light brown, smooth, 9-14 mm. long, 1.5-3 mm. wide, equaling the bradle: tubillus straight, con- spieuously exserted, the twisted ligulate limb 1 mm. long. Distribution: southwestern Texas and southern New Mex- ico to California, and adjacent Mexico. SPECIMENS EXAMINED: ТЕХАБ: Limpia Canyon, May 1915, Allen 177 (G, M); in gravel, ego foothills, Franklin Mts., Canutillo, El Paso Co., 3 July 1911, Barlow (Е); s places near El Pas о Бок 8 (6); pila. 3 mm d. of UM Piedra, LE Co., 21 Feb. 1937, (dir 622 (G, M, P, UW); sands west т gap, Dog Canyon, ac Mts., Brewster Co., 27 May 1938, Cutler 1852-1859 (M); along adi bottom, 3 nd southeast of Castolon, Brewster Co., 29 May 1938, Cutler 1877, 1879, 1881 (M); sandy plain, 8 miles northwest of Решо, Мек idio Co., 31 May 1938, Cutler 1920 (M); Es dry ereek, 17 miles north of Shafter, Presidio Co., 1 June 1938, Cutler 1942, 1943 (M); along railroad, 9 miles west of Marfa, Presiilio Co., 1 June 1938, QUE 1952 (M); in sand, form је hummocks, 12 miles northeast of 8 12 May 1901, Eggert (M) ; Mt. Livermore, May 1936, Hinckley 257 (F); El рын, 17 April 1884, Jones 3717 (CA, F, NMAM, P); Marathon, 23 April 1930, Jones [Vor. 26 386 ANNALS OF THE MISSOURI BOTANICAL GARDEN 26403 (M, P); about 5 miles west of Alpine, Brewster Co., 25 April 1931, McKelvey 1997, 1998 (P); Boquillas, Brewster Co., 20 July 1937, Mari 143 (F); 4 plain, 3 miles west of Mt. Livermore, Davis Mts., alt. 1800 m., 14 June 1931, Moor $ Steyermark 3083 (СА, G, М); ; gravelly desert, west side of Chisos Mts., alt. 1008 m., Brewster Co., 27 June 1931, Moore $ Steyermark 3287 (СА, а, M); Hueco Tanks, 1 July 1895, Mulford 187, 187a (M) ; low hills near Fort Davis, 7 July 1917, Munz 1408 (P); rocky open ground, upper Limpia Canyon, Jeff Davis Co., 17 June 1926, Palmer 30989 (М); Barstow, и April 1902, Tracy 4 Earle 66 (Е, М); Alla- more, 23 April 1932, Whitehouse 8 New Mexico: sandy fields, 7 ien north-northeast of Oro Grand, Otero Co., 4 June 1938, Cutler 1983, 1984 iL along creek bed, Rhodes Pass, 30 miles east of Engle, 5 June 1938, Cutler 2019 (M); fields, 3 miles west of Elephant Butte Dam, Sierra Co., 7 June 1938, Cutler 2068-2074 (M); on ereosote-bush desert near San Marcial, 23 Feb. 19M, Detwiler 21 (Е); near Silver City, 3 April 1919, East- wood 8192, $193 (CA); Nutt, 1420 m., Luna Co., 6 Oct. 1919, Eggleston 16269 (F); along the Gila River and on the mesa above Cliff, Grant Co., 24 Oct. 1919, Eggleston 16508 (M); ‘‘From the region between the Del Norte and the Gila, and the hills bordering the latter river to the desert west of the Colorado,’’ Emory Exp. (TYPE, not seen); wash, 3 miles west of Pyramid Peak, alt. 1200 m., Dona Ana Co., 29 Aug. 1930, Fosberg S3474 (P); pss 2r ug. pe peut (UNM); Bowdird, eed Greene (F); Lordsburg, 9 April 1930, Jones 259 Deming, 9 April 1930, Jones 26402 (M, P); Organ Mts., ^in ген otn 1931, Layton (I); Mangas айына 18 miles seil кегі of Silver City, Grant Co., 26 Sept. 1903, Metcalfe 811 (M); hillside near Albuquerque, alt. 1200 m., 17 Dee. 1936, Miers (UNM); Deming, 31 Aug. 1895, Mutford 1025 (I, M); dry мее hills along the Rio Grande near Caballo Dam, 17 miles east of Hillsboro, Sierra Co., 15 June 1938, Ownbey $ Ownbey 1633 (M); desert plain 8 miles northeast of “үле бег Hidalgo Co., 19 June 1938, Ownbey $ Ownbey 1647 (M); Dry Canyon, Sacramento ts., Alamogordo, alt. 1400 m., 9 April 1902, Rehn 4: Viereck (P, В); San Antonio, 1883, Rusby (Е); mesa west of Agricultural College, 3 May 1906, Standley 38 (М); mesa, west of Organ Mts., 22 June 1906, Standley 441 (M); sandy soil, Valverde, 31 July 1846, Wislizenus 58 (M); mesa, near Las Cruces, 10 May 1892, Wooton 426 (NMAM) ; mesa, near Las Cruces, alt. 1250 m., 5 July 1897, Wooton 96 (6, M, Р); mesa, — of the Organ Mts., Dona Ana Co., 22 April 1899, Wooton (NMAM); mesa, west of Organ Mts., Dona Ana Co., alt. 1230 m., 19 April 1905, Wooton (Т, NM = ў сон and Donnana, coll. of 1851-52, Wright 1884 (G, M). ONA: San Bernardino Valley, 1930 m., Cochise Co., 18 April 1928, ARI : эй (CA, Р); mesa, north of Rillito x Pins. Co., 16 Jan. 1920, Bartram 16 (P); Yuma, 3 April 1914, Carlson pone. highway 60, near Globe, 1050 m., Gila Co., 21 April 1935, Collom 341 (M); Yuma, 22 April 1917, Eastwood 6348 (СА); canyon, Santa Rita Mts., Tucson, 22 March 1919, Жекей 8115 (СА); Bowie, 16 Мау 1919, Eastwood 8624 (CA) ; along road from Packard to Payson, 1 Nov. 1928, Eastwood 16606 (CA); on the road from Prescott to Phoenix, 11 Nov. 1928, East- wood 16608 (CA); Sierra Ancha, 7 May 1929, Eastwood 16950 (CA); Mazatzal Mts., 12 May 1929, Eastwood 17169 (CA); on road between Globe and Roosevelt, 24 May 1929, Eastwood 17447 (CA); Pinal Mts., 18 May 1929, Eastwood 17526 (CA); on road to Rincon Mts., 19 March 1930, Eastwood 17805, 17811 (СА, G); чр" CERTA ESTE 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 387 Cochise, Feb. 1927, Ellis $ Ledman (М); on the mesa, north of the Santa Rita Mts., 28 Sept. 1880, Engelmann (M); Roadside Mine, Pima Co., 3 April 1932, Fosberg (M, P); Douglas, 22 May 1907, Goodding igh ee desert Ба nod north of ioia. 4 April 1 1913, Greenman $ Greenman (M); small range reservation near Tucson, 13 March to 23 April 1903, Grifiths Me (M); Benet тана, а. 900 m., 2 May 1903, Jones (Р); fade. alt. 1400 m., 28 Aug. 1903, Jones (P); Rodeo, 8 April 1930, Jones 26400 (M, P); Stein's, 6 My 1930, Jones hes ; (СА, M, P); Benson, 6 April 1930, Jones 26401 (P); Sulphur Springs É age 18 May 1921, W.W. Jones 434 (б); mesas, near Tucson, spring 1907, Lloyd (Е, G); Yuma desert at Monument 204, International Boundary, 17 Магеһ 1894, p us 2826 (S); sand dunes, south of Wellton, Gila Desert, ip 1916, Monnet 1110 (СА); rocky uos 25 miles west of Casa Grande City, 22 March 1935, Nelson § Nelson 1259 (М, R); sandy Yuma desert near U.S.-Mexican boundary, 26 March 1935, Nelson $ Nelson 1290 (M, В); near Cochise, Ў April 1935, Nelson $ Nelson 1619 ( Tueson, 2 Feb. 1926, Nuttall i. F, P); Mohave Ageney, 1 April 1876, Paine 528% (С, M); Tink 20 March 1881, Parish $ Parish 753 (Е, G); Tucson, April 1884, Parish 0 Lowell, May 1884, Parish (I); p, ra Springs Valley, 13 April 1894, Price (8); mesas, 29 April 1881, Pringle (F, G, М); mesa, near Tueson, 2 April 1888, Pringle (Е) ; mesa, near Tueson, 21 April 1884, Pringle (F); ns near Clifton, Reynolds (СА); wash, west of Desert Lab., Tueson, 22 June 1908, Sherff (F); mesas, near Tueson, 8 April 1917, Shreve 5158 (G); 5 miles west bi de Cochise Co., 30 April 1933, Shreve 6282 (F); Gila, June 1852, Thurber 681 (G); in sand, 7 miles south of Parker on the Bouse road, Yuma Co. 14 April 1922, Wiegand § Upton 2979 (Е); flats of Desert Lab., Tucson, 15 March 1933, Wiggins 6508 (Р); 42 miles northeast of Douglas on road to Rodeo, alt. 1350 m., 7 July 1928, Wolf 2555 (CA, G, P). CALIFORNIA: near Salton Sea, 6 March 1922, Campbell (CA, P); sand hills, Yuma-El Centro road, Imperial Co., 19 April 1928, Ferris 7128 (P); Yaqui Well, Colorado Desert, 21 Jan. 1926, Jones (P); Imperial Co., near Arizona, 13 March 1920, Kline (UW); sand dunes between El Centro, Imperial Co., and Yuma, Ari- zona, 25 March 1936, MacFadden 14476 (CA); Laguna Station, 6 May 1894, Mearns 2937 (8); under overhanging roeks, foot of Mountain Springs Grade, Im- perial Co., 23 Feb. 1924, Munz 7823 (G, P); Colorado desert near Yuma, 27 Dec. 1880, Parry (I, M); Agua рр April 1882, Parry (M); sand dunes, west of Fort Yuma, Imperial Co., 15 April 1927, Bere 7193 (P); sandy soil, Colorado Desert, 12 miles хони » Westmorland, below sea-level, Imperial Co., 12 March 1931, Wolf 1870, 1871 (CA). MEXICO: COAHUILA: Del Carmen Mts., 29 т 1936, Marsh 694 (F). CHIHUAHUA: San Diego, alt. 1830 m., 10 April 1891, Hartman 642 (G, US); Sierra Madre, 21 June-29 July 1899, мање 6014 (05); n of Chihuahua, about E m., 8-27 April 1908, Palmer 68 (F, G, M, US); vieinity of Chihuahua, about 130 , 1-21 Мау 1908, Palmer 172 (US); Chihuahua, 1885, Pringle 88 (G) ; mesas, near Chihuahua, 7 April 1886, Pringle $68 (F, US) ; mesas, Chihuahua, 20 May 1887, Pringle pe (Е); 11 Мау 1899, Rose $ Hough 4928 (US); Sta. Eulalia plains, 13 April 1885, n m 117 (I, US), in part; Sta. Eulalia plains, 2 April 1886, bs 120 (I, U [Vor. 26 388 ANNALS OF THE MISSOURI BOTANICAL GARDEN SONORA: coast of Gulf of California near upper end, 1910, Lwmholtz 24 (G); Colorado River at Colonia Diaz, 24 March 1894, Mearns 417 (08); Lower Colorado, 1869, Palmer (US). BAJA CALIFORNIA: Gardner’s Laguna, 27 April 1894, Mearns $ Schoenfeldt 2916 8). E. trifurca is easily recognized by the yellowed and spi- nosely-tipped branches and the frayed but persistent leaves of the older stems. Тһе species is very constant throughout its entire range. 2. x Ephedra intermixta Cutler,” n. hyb. (= Ephedra trifurca x Torreyana ). Erect dioecious shrub, 0.5-1.5 m. high; branches rigid, solid, terete, up to 3.5 mm. thick, solitary or whorled at the nodes, angle of divergence 35-40 degrees; internodes 1-5 em. long; young stems pale green, smooth and glaucous, with numerous small longitudinal furrows, becoming yellowed; bark cine- reous, cracked and fissured; terminal buds spinose to obtuse- conical; leaves ternate, 3-6 mm. long, acutely tipped from a dorso-median thickening, connate for three-fourths their length at first, soon splitting; sheath membranaceous, later fis- sured; staminate spikes at the nodes of the young branches, ovate, 3-7 mm. long, sessile or short-pedunculate, bracts ter- nate, in 3-7 whorls, obovate, 2-3 mm. long, 2 mm. broad, mem- *x Ephedra intermixta Cutler, hyb. nov.; frutex мінде гарну 0.5-1.5 m altus; ramulis rigidis, solidis, teretibus, ком ad 3.5 m ametro, ad nodos solitariis vel verticillatis, angulo declinationis circiter 55-40%; инв 1-5 em. longis; eaulibus juventate pallide viridibus, laevibus et glaucis, tenuissime striatis, einde lutescentibus; rhytidoma cinerea, rimosa, sulcata; gemmis terminalibus pungentibus vel eonieis; foliis ternatis, 3-6 mm. longis, ad apieem pungentibus ex dorso-medio crassificatione, primo ad 94 longitudinis connatis, deinde diffisis; vagina membranaeea, deinde “e pares stamineis solitariis vel multis nodos ramulorum n novorum, ovatis, 3-7 mm. longis, sessilibus vel brevi- ee bracteis ternatis, in 3-7 v vettiatitis, кан 2-3 mm. longis, 2 mm branaceis, vellids n vel pallide din vertieillis inferioribus vacuis; ренин bracteas subtendentes subaequantibus; columna staminalis 2-5 mm. longa, 2% exserta, 4-7 antheris brevi-stipitatis ; spicis femineis solitariis vel muitis ad nodos ramulorum novorum, obovatis, 4—7 mm. longis, sessilibus vel bre uiia bracteis ternatis, in vertieilis 5-7, suborbieularibus, unguiculatis, marginibus yalinis, erosis, 4-7 mm. longis, 4-6 mm. latis, membranaceis, pallide luteis; semini- bus plerumque көнетін. tri- aut tetragonatis, pallide fulvis, laevibus, 4-6 mm longis; tubillo recto, multo exserto, limbo ligulato contorto 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 389 branaceous, light yellow to light brown, the lower whorls empty; perianth almost equaling the subtending bract; stami- nal column 2-5 mm. long, one-half exserted, with 4-7 short- stipitate anthers; ovulate spikes solitary or numerous at the nodes of the young branches, obovate, 4-7 mm. long, sessile or short pedunculate, bracts ternate, in 5-7 whorls, suborbicular, unguiculate, hyaline margins erose, 4-7 mm. long, 4-6 mm. broad, membranaceous, light yellow; seed usually solitary, tri- or tetragonal, light brown, smooth, 4-6 mm. long; tubillus straight, ОШО exserted, the ligulate limb contorted. SPECIMENS EXAMINED NEW MEXICO: gen ый, Rhodes Pass 30 miles east of Engle, 5 June 1938, Cutler 2020, 2021 (G, M, US); fields, 3 miles west of Elephant Butte Dam, Sierra Co., 7 June 1938, Cutler 2075 (G, М туре, T, US), 2078 (G, M, T, US). While making field studies several cases of possible hybridi- zation were observed. Specimens intermediate between E. trifurca and E. Torreyana were collected both in sandy washes and creek beds, the usual habitat of E. trifurca, and in gravelly and sandy fields, the habitat of E. Torreyana. The preference of stock for the latter and for E. intermiata aids in the field of identification of these two. A comparison with the parent species follows: x E. intermizta E. trifurca Searcely ever eaten by stock. Numerous branches at а Angle of branch-diver- gence about 30° Average internode 3.6 em. Leaves up to 10 mm. long. Bracts usually brown, margins entire. Seeds smooth and light brown 3. Ephedra Torreyana Watson in Proc. 1879 Eaten by stock. Numerous to few at a node. Angle of branch- "ipd gence about 35-4 Average internode 2.6 em. Leaves up to 6 mm. long. Braets from brown and entire to yellow and erose. Seeds smooth and light brown E. Torreyana Eaten by stock. Few branehes at a node. Angle of branch-diver- репсе about 48% Average internode 2.4 em. Leaves up to 3.5 mm. long. Braets usually yellow, margins erose. Seeds scabrous and light yellow Am. Aead. 14: 299. Е. trifurca Parry in Am. Nat. 9: 351. 1875. [Vor. 26 390 ANNALS OF THE MISSOURI BOTANICAL GARDEN E. antisyphilitica f. monstrosa Torr. ex Stapf in Denkschr. K. Akad. Wiss. Wien 56?: 43. 1889. Erect dioecious shrub, 0.25-1 m. high; branches rigid, hard, terete, up to 3.5 mm. thick, solitary or whorled at the nodes, angle of divergence about 48? ; internodes 2-5 em. long; young stems pale blue-green, glaucous, almost smooth with many small longitudinal furrows, becoming gray; bark of older stems cinereous, cracked and irregularly fissured; terminal buds less than 4 mm. long, conical but not spinose; leaves ter- nately whorled, 2-5 mm. long, obtusely, occasionally acutely, pointed from a brownish-green dorso-median thickening, con- nate for one- to two-thirds their total length, but later spread- ing and recurved; sheath at first membranaceous, later fis- sured, thickened and grayed, subpersistent; staminate spikes solitary to four in a whorl at the nodes of the young branches, ovate, 6-8 mm. long, sessile; bracts ternate, in 6-9 whorls, ovate, slightly clawed, 2-3.5 mm. long, 2-3 mm. broad, mem- branaceous, cream-coloured to pale yellow, the lower whorls empty; perianth exceeding the subtending bract; staminal eolumn 2.5—4 mm. long, one-fourth to one-half exserted, with 9-8 sessile or short-stipitate anthers; ovulate spikes solitary or several in a whorl at the nodes of the young branches, ovate, 9-13 mm. long, sessile, bracts ternate, in 5-6 whorls, obovate, clawed, 6-9 mm. long, 6-10 mm. broad, hyaline except for the orange-yellow to greenish-yellow center and basal portion, margins minutely toothed, undulate; seed solitary or two, oc- casionally three, trigonal or tetragonal, light brown to yellow- green, scabrous, 7-10 mm. long, 1.6-3 mm. wide, equaling or slightly exceeding the bracts; tubillus straight, conspicuously exserted, the contorted ligulate limb 1 mm. long. Distribution: western Colorado to western Texas and west- ward to northern Arizona and Nevada. SPECIMENS EXAMINED: TEXAS: cottonwoods near El Paso, Bigelow 4 (G, M); 11.15 miles southwest of Big Springs, Howard Со., 18 April 1930 Cory 2829 (P); dry steep calcium breaks of Palo Duro Canyon, Randall Co., 31 July 1934, Goodman 2230 (M); dry rocky slopes of Palo Duro Canyon, Randall Co., 3 June 1918, Palmer 13873 (M, UW)I dry rocky slopes, Channing, Hartley Co., 19 June 1918, Palmer 14155 (M, UW); 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 391 Frontera, 1852, Parry (M); sandy hills near Frontera, 26 April 1851, Wright 1888 (G TYPE, М) in part. Соговаро: Deer Run, region of the Gunnison Watershed, alt. 1430 m., 25 Aug. 1901, Baker 921 (G, М); Grand Junction, May 1892, Eastwood (С); Grand June- i ‚ Gr 1350 dry hillside, alt. 1760 m., 7 June 1913, Payson 108 (F, G, M); dry hillside, alt. 1650 m., Naturita, 19 May 1914, Payson 319 (F, G, I, M); dry rocky hillside, alt. 1650 m., Naturita, 26 May 1914, Payson 353 (F, G, I, M); shale hills, Ridgeway, 17 June 1924, Payson $ Payson 3833 (G, М); clay to sandy hillside near E Gunnison River, 6 miles west of Delta, Delta Co., 27 Aug. 1937, Rollins x pb M). New Mexico: San Ysidro, 1700 ft., 9 Feb. 1927, Arséne 19034 (F); Carlsbad, 1 May 1929, Benke 5022 (F); Шеп, АйБафЧегуйб, 23 March 1918, Collins (G) ; Pena Blanea, alt. 1600 m., 21 May 1930, Curtin 108 (F); fields and along railroad E à ies north of M uas Otero Co., 4 June 1938, Cutler 1987, 1988, 1990-1997 (M); White Sands, 13 miles w. of Tularosa, Otero Co., 5 June 1938, Cu d ние 15 (М); Јогпада p Muerto, 4 miles east of Engle, Sierra Co., 6 June 1938, Cutler 2049—2053 (M); 7 miles west of Engle, Sierra Co., 7 June 1938, Cutler 2061, 2062 (М); in fields, 3 miles west of Elephant Butte Dam, Sierra Co., 7 June 1938, Cutler 2076, 2077, 2079 (M); Farmington, 8 June 1899, Diehl (P); n soft ‘‘Santa Fe?" gravels, San Juan, west side of Rio Grande, Rio Arriba Co., 23 June 1932, Godwin (G); Red Valley, on Cuba-San Ysidro road, 7 July 1932, Goodwin (G); banks of the Rio Grande River, 19 miles west of Santa Fe, alt. 1650 m., 31 Мау 1897, Heller § Heller 3623 (M); Albuquerque, 14 April 1884, Jones (P); Rineon, 30 May 1884, Jones s Organ Pass, 3 May 1930, Jones (P); sand dunes west of Alamogordo, 3 May 1930, Jones 25962, 25964m (CA, M, P); mesa about two miles east of онна alt. 1520 m., 1915, Каттетет 5 (M); desert hills west of valley, Santa Cruz, Santa Fe Co., 30 өші 1936, Marcelline 1840 (F); sand hills along Cuba Road, near Bloomfield, San Juan Co., 5 July 1929, Mathias 613, 614 (G, M, P); Santa Fe, June 1874, Rothrock 80 (Е, б); White Sands, Dona Ana Co. 16 July 1897, Wooton 568 (M); mesa west of the Organ Mts., near Little Mt., Dona Ana Co., 11 May 1902, Wooton (NMAM); San Andreas Mts., Jan. 1907, Wooton (NMAM); med 35 miles south of Torrance, alt. eid m., 10 Aug. 1909, Wooton (NMAM); coll. of 1851-2, Wright 1882 (M) in p RIZONA: sandy and roeky soil of mesa, Lee's Ferry, 6 July pe Cottam 2611 (BYU); rough hills, Fort Whipple, Sept. 1865, Cowes $ Palmer 570 (М); on sands and among y 24 of mesa 5 miles west of Rock Point, Apache Co., 15 June 1938, Cutler 2198, 9 (M); sands, 5 Su south of Dennehotso, Apache Co., 15 June 1938, Cu tler uo —2218, B. 2220 (M); bluffs, edge of Painted Desert, 20 Oct. 1928, Eastwood 15720 (CA); between Tuba City and Tonalea, Coconino Co., 10 Sept. 1938, Eastwood $ Howell (CA); Bright Angel Trail, Grand Canyon, 24 May 1903, Grant (S); rocky soil near Cameron, alt. 1520 m., 7 June 1922, Hanson A166 (F, M); Holbrook, May 1900, Hough (F, G); Yucca, 13 April 1884, Jones (P); Pierce’s Ferry, 426 m., 19 April 1894, ли 5077az (P); Bonelli’s Ferry, 800 ft., 13 April 1903, Jones (P); between Holbrook and Snowflake, 19 May 1931, Mc- Kelvey 2287, 2288 (P) ; desert plain between Flagstaff and Holbrook, 26 Мау 1935, Nelson 4: Nelson 2136 (М); 12 miles northeast of Tuba City, alt. 1600 m., 3 June 1935, Peebles § Fulton 11874 (СА); Monument Valley, alt. 1600 m., Navajo Co., 4 [Vor. 26 392 ANNALS OF THE MISSOURI BOTANICAL GARDEN June 1935, Peebles L Fulton 11940 (P); Grand Falls of the Little Э: e Coconino Co., Whiting 756 (UNM); open prairie, Flagstaff road, 5 miles west of Winslow. Coconino Co., 22 May 1922, Wiegand 4 Upton ye gr Uram: dry hills, Green River, alt. 1380 m., Emery Co., 6 June 1927, Cottam 2077 (BYU); dry sandy hillside, 10 miles north of Moab, Grand Co., 8 May 1935, Cottam 6843 (BYU); on sand and gravel, Copper Canyon, 7 miles northwest of Oljato Post, San Juan Co. 16 June 1938, Cutler 2232, 2245, 2261, 2262 (M); sand flat, San Juan Canyon, 2 miles ма of көме sir Hat, San Juan Co., 20 June 1938, Cutler 2320 (M); hills above Comb Wash, 8 miles west of Bluff, San Juan Co., 21 June 1938, Cutler 2327 (M); 10 miles north of Bluff, San Juan Co., 21 June 1938, Cutler 2342 (М); Snake Creek, San Juan Co., 15 Sept. 1938, East- wood ф Howell 6704 (CA); dry hillside, red sandstone жар, north of St. George, 6 April 1935, Galway (BYU); Santa Clara Creek, 20 May 1902, Goodding 6?7a (M); west of Green River, between river and quarry ledge, 20 miles south of Vernal, alt. 1430 m., Uintah Co., 19 June 1981, Graham 6123 (М); flat above quarry ledge, west side a Green River, 20 miles south of Vernal, alt. 1460 m., 20 June 1931, Graham 6171 (M); on тоску south slope of Leland Bench, sunt north of 0 m., Uintah Co., 22 May 1935, Graham 8933 (M); red hill north of St. George, 8 May 1935, Hall (BYU); dry sandy hills, Sugar Loaf Mt., St. George, Washington Co., 15 May 1932, Harrison 301 (BYU, M); dry sandy wash, Dirty- Devil River canyon, alt. 2115 m., Fruita, Wayne Co., 6 April 1934, Harrison 7398 ear Lower Crossing, 9 July 1866, Jones (P); Green River, 9 May 1890, Jones (P); red sand, St. George, alt. 900 m., 26 April 1894, Jones 5110aq (P); San Rafael Swell, 28 May 1914, Jones (S); southern Utah, 1874, Parry 250 (G, M); shale outerops near Willow Creek, 22 miles south of Ouray, Uintah Basin, Uintah Co., alt. 1825 m., 16 June 1937, Rollins 1719 (6); Granite Creek at foot of the Henry Mts., alt. 1520 m., 5 July 1930, Stanton 331 (BYU); streamside-washes, Crescent Creek, Henry Mts., alt. 1825 m., 15 July 1930, Stanton 437 (BYU); slopes and mesas west of St. George, 5 May 1919, Tidestrom 9300 (6, M NEVADA: 5 miles northwest of Las Vegas, 10 May 1938, Barkley $232 (M); limestone dn south of Indian Springs, 1250 m., Clark Co., 12 May 1938, Clokey 7816 M); open hillsides, Dry Lake, 17 April 1905, Gooding 2234a (G, M, P); red sand, St. Joe, alt. 425 m., 7 April 1894, Jones 5029af, 5029ag (P); Moapa, alt. 425 m., 27 April 1904, Jones (Р); Amargosa Desert, alt. 1215 m., 27 April 1907, Jones (P); Moapa, alt. 517 m., 12 May 1905, Kennedy (M); rocky hillside 6 miles north of Alamo, Lincoln Co., 1934, Maguire, Maguire § Maguire 4715 (M); dry roeky slopes, vieinity publie eamp, Valley of Fire, Clark Co., 5 April 1934, Maguire, Maguire ф Maguire 4722 (M). MEXICO: CHIHUAHUA: near Ojo de Vaca, May 1851, Thurber 304 (G). Ephedra Torreyana is not as constant throughout its range as E. trifurca. Specimens from St. George, Utah, and to the northwest, differ in having the ovulate bracts brighter yellow, more crenulate and more undulate. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 393 4. x Ephedra arenicola Cutler,?9 n. hyb. (= Ephedra Torreyana x Соту var. viscida Cutler). Dioecious shrub, 0.25-1 m. high; branches flexuous, terete, up to 3 mm. thick, opposite or whorled at the nodes, angle of divergence about 35 degrees; internodes 2-5.5 cm. long; young stems green, viscid, slightly rough, with numerous small longi- tudinal furrows, becoming yellowed; bark cinereous, cracked and fissured; terminal buds subuliform; leaves binate or ter- nate, 2-6 mm. long, obtusely to setaceously tipped from a dorso-median thickening, connate for two-thirds their length at first, later splitting; staminate specimens not seen; ovulate spikes solitary to many at the nodes of the young branches, peduncles 5-50 mm. long, bracts binate, in 4-6 whorls, slightly unguiculate, narrowly elliptic, 3-8 mm. long, 2-5 mm. broad, membranaceous, margins hyaline and erose; seeds paired, one frequently aborted, scabrous, light brown to light yellow, 4-7 mm. long, almost equaling the bracts; tubillus straight to somewhat curved, slightly exserted, the ligulate limb con- torted. SPECIMENS EXAMINED ARIZONA: sands, 5 miles south of Dennehotso, Apache Co., 15 June 1938, Cutler 2217 (G, M, T, US), 2221 (6, М түре, T, US) Among typical Е. Coryi var. viscida growing upon loose sands was found a hybrid with E. Torreyana which grows near by on slightly more stable and rocky areas. A comparison of the hybrid with the parent plants follows: x Ephedra arenicola Cutler, v nov.; frutex dioieeus, 0.25-1 m. altus; r i s flexuosis, teretibus, usque mm. in diametro, ad nodos oppositis vel vertieillatis, angulo declinationis id 35°; кан iis 2-5.5 em. longis; caulibus juventate viridibus, viseidis, parce seabris, tenuissime striatis, deinde lutescentibus ; rhytidoma cinerea, rimosa, suleata; pe gs terminalibus subulatis; foliis binis vel ternatis, 2-6 mm. longis, ad apieem obtusis vel im gentibus ex dorso-medio crassificatione, primo ad % Pu. eonnatis, deinde diffisis; spieis stamineis ihi ignotis; spicis femineis solitariis vel multis D nodos ас A novorum, peduneulis 5-50 mm. nd bracteis oppositis, in verticillis 4-6, parce unguieulatis, vicam elliptieis, 3-8 m ongis, 2-5 mm. latis, membranaceis, marginibus hya- nis erosis; seminibus piis, А uno saepe abortivo, scabriuseulis, pallide fulvis "a pallide luteis, 4-7 mm. longis, braeteas subaequantibus; tubillo recto vel parce eurvato, leviter exserto, limbo da ia contorto. 394 ANNALS OF E. Torreyana Average internode 2.4 em. Angle of branch-diver- gence about 48°. Stem not viseid. Leaves ternate. Leaves short, obtuse, per- sistent. Ovulate strobilus sessile. Bracts ternate. Bracts dry, membrana- ceous, clawed Seeds light and scabrous. [Vor. 26 THE MISSOURI BOTANICAL GARDEN E. arenicola Average internode 3.5 em. Angle of branch-diver- gence about 35° Stem viscid. Leaves binate and ter- Leaves long, setaceous, persistent. Ovulate strobilus long- peduncled. Bracts binate. Bracts dry, membrana- eeous, slightly clawed. Seeds light and scabrous. E. Coryi var. viscida Average internode 3.6 em. Angle of branch-diver- gence about 28° Stem viscid. Leaves binate. Leaves long, setaceous, eciduous. Ovulate strobilus long- eduneled. Braets binate. Braets succulent, connate base. Seeds dark and smooth. 5. жеді funerea Coville & Morton іп Jour. Wash. Acad. Sei. 25: 307. 1935. Егесі dioecious shrub, 0.25-1.5 m. high; branches stiff, hard, terete, up to 3.5 mm. thick, solitary or several, usually three, at the nodes, angle of divergence about 60 degrees; internodes 2-6 em. long; young stems pale gray-green, glaucous, slightly roughened, glandulose, with many small longitudinal furrows, later gray ; bark of older stems cinereous, slightly cracked and fissured; terminal buds 1-4 mm. long, acute-conical, not spinose; leaves ternately whorled, 3-6 mm. long, acutely pointed from a dorso-median thickening, at first connate for one-half to two-thirds their total length, later splitting along the margins and spreading slightly, persistent; staminate spikes one, two or three, at the nodes of the young branches, elongate-elliptie, 5-8 mm. long, sessile or borne on very short scaly-bracted peduncles, bracts ternate, in 6-9 whorls, ovate, short-clawed, 3-4 mm. long, 2-3 mm. broad, membranaceous, yellowish, the lower whorl empty; perianth equaling the sub- tending bracts; staminal column 3-4 mm. long, one-third ex- serted, with 4—7 sessile or very short-stipitate anthers; ovu- late spikes one, two or three, at the nodes of the young branches, lanceolate-obovate, 8-13 mm. long, on short scaly-bracted peduncles, or sessile, bracts ternate, іп 6-9 whorls, elongate- 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 395 obovate, broadly clawed, 4-8 mm. long, 3-5 mm. broad, yellow- translucent except for the green thickened central portion, margins slightly dentate; seed solitary, or rarely, two or three, tetragonal, pale green to light brown, smooth to scabrous, 6-9 mm. long, 2-3.5 mm. wide, equaling or barely exceeding the bracts; tubillus straight, exserted, the truncate tip slightly contorted. Distribution: Death Valley region, California, to Nevada. SPECIMENS EXAMINED: CALIFORNIA, DEATH VALLEY REGION: mountain side below Dante’s View, 1500 m., 7 April 1935, Clokey & Templeton 5675, 5676 (Clo, M); Furnace Creek Canyon, alt. 870 m., 16 April 1931, Coville $ Gilman 19 (US); Furnace Creek Canyon, alt. 940 m., 18 April 1931, Coville $ Gilman 108 (US); Boundary Canyon, alt. 1065 m., 24 April 1932, Coville $ Gilman 407—410 (US); Furnace Creek Canyon, near the old town of Ryan, alt. 900 m., 25 April 1932, а id Gilman 444, 445 (US); Furnace Creek Canyon, on the Бекі: Shoshone road, . 980 m., 26 April 1932, Coville $ Gilman 447 (US ТУРЕ); Furnace Creek rims i Зенон of the Dante's View road with the Ryan-Shoshone road, alt. 1020 m., 26 April 1932, Coville 4. Gil- man 448 (US); Warm Springs Canyon, Panamint Mts., about a mile above Warm Springs, alt. 790 m., 30 April 1932, Coville $ Gilman 502, 502A (US); Furnace Creek Wash, 6 April 1928, Craig 919 (М); hillside, Ryan, 17-24 Магеһ 1924, Ferris, Scott § Bacigalupi 4036 (S); rocky hillside 1 mile south of Ryan, 16 April 1932, Hitch- cock 12329 (M, P, US); sandy open, 2 miles east of Bradbury Well, Black Mts., 2 April 1928, Howell 3643 (CA); Funereal Mts., alt. 1200 m., 10 April 1907, Jones МЕУАРА: gravelly hills, Arden-Mountain Springs, mile 11, alt. 1100 m., Charles- ton Mts., Clark Co., 22 April 1939, Clokey 8225 (Clo, M). 6. Ephedra californica Watson in Proc. Am. Acad. 14: 300. 1879. Erect or spreading dioecious shrub, 0.3-1 m. high; branches semiflexible to rigid, hard, terete, up to 4 mm. thick, solitary or whorled at the nodes, angle of divergence about 45 degrees; internodes 3-6 em. long; young stems yellow-green, glaucous, almost smooth, with numerous longitudinal furrows, becoming yellow, then yellow-brown; bark of older stems gray-brown, eracked and irregularly fissured; terminal buds 2-3 mm. long, acute, conical; leaves ternately whorled, 2-6 mm. long, obtusely to acutely tipped from a green-brown dorso-median thicken- ing, connate from one-half to three-fourths their total length; sheath at first membranaceous, later thickened, becoming [Vor. 26 396 ANNALS OF THE MISSOURI BOTANICAL GARDEN brown, hard and fibrous, splitting and recurving, subpersist- ent; staminate spike solitary or several in a whorl at the nodes of the young branches, ovate, 6-7.5 mm. long, short-peduneu- late, peduncles many-scaled, bracts ternate, in 8-12 whorls, ovate, slightly united at the base, 2.5-3 mm. long and broad, membranaceous, light orange-yellow except for the hyaline margins, the lower whorls empty ; perianth equaling or slightly exceeding the subtending bract ; staminal column 3-5 mm. long, one-third exserted, with 3-7 sessile or short-stipitate anthers; ovulate spikes solitary or several in a whorl at the nodes of the young branches, ovate, 7-10 mm. long, very short- and scaly-pedunculate, bracts ternate, in 4-6 whorls, orbicular, very slightly unguiculate, 5-7 mm. long, 5-10 mm. broad, pale yellow-translucent except for the orange- or green-yellow cen- ter and basal portions, margins entire; seed solitary, rarely two, nearly globular but indistinctly tetragonal, light to dark brown or chestnut, smooth, 7-9 mm. in diameter, equaling or slightly exceeding the bracts; tubillus straight, barely ex- serted, with a short ligulate, scarcely contorted limb. Distribution: southern California and adjacent Arizona, and northern Baja California. SPECIMENS EXAMINED ARIZONA: Kinguan-Y Pu road, Mohave Со., 26 March 1927, Вғает (8). CALIFORNIA: Palm Springs, Riverside Co., 6 April 1903, Abrams 5204 (CA, P); hills near Tia Juana, 14 May 1903, Abrams 3489 (G, M, P, 8); dry hillsides near Campo, San Diego Co., 24 May 1903, Abrams 3600 (G, M, P, 8) ; Jacumba, 31 Ma 1903, Abrams 3675 in part (S) ; Palm "p id 17 April 1926, Atsalt (М); granite soil, Mt. Breckenridge, alt. 900 m., Kern Co., 23 April 1932, Benson 3358 (S); North Island, 7 May 1904, Chandler. 5165 (8); | Coronado, alt. 3 m., near San Diego, June 1893, Cleveland (8); mouth of Mosaic Canyon, sea level, Death Valley region, 6 April 1935, Clokey $ Templeton 5784 (Clo, М); field at Coronado, 26 Dee. 1908, Dudley (8); Caliente Mts., baek of Painted Rock, San Luis Obispo Co., June 1927, Dudley (CA); near Ozena P. O., Ventura Co., Мау 1936, Dudley (CA); North Coronado, San Diego Co., 7 April 1913, Eastwood 2570, 2571 (CA); San Felipe Canyon, Colorado Desert, San Diego Co., 14 April 1913, Eastwood 2782 (CA); Grapevine Creek, Colorado Desert, San Diego Co., 14 April 1913, Eastwood 2808 (CA); Tia Juana, San Diego Co., 24 April 1913, Eastwood 2911 (CA); Palm Springs, San Bernardino Co., 30 PN 1913, Eastwood 3082 (CA) ; Warren's ranch Campo, San Diego Co., 22 pee 1920, Eastwood 9412, 9413 (CA) ; Coalinga, Fresno Со., 31 March 1926, pet twood 13453 (CA); near Mountain Spring, San Diego Co., 25 April 1932, Eastwood 18641 (CA) ; Morongo Valley, San Bernardino Co., 28 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 397 May 1932, Eastwood 18687 (CA); on road from Barstow to Las Vegas, San Ber- nardino Co., 30 April 1932, Eastwood 18766 (CA); on road pe тере to Las Vegas, San Bernardino Co. 30 April 1932, Eastwood 18798 (CA); EP Creek, southeast of Panoche, San Benito Co., 3 May 1937, Ea $ Howell 4278, 4274 (CA); Little Panoche Pass, San Benito Со., 19 April 1938, Ed 4 Howell 5129, 5130 (СА); Sacumba Springs, San Diego Co., 11-16 April 1924, Eg- gleston 19706 (CA, P); sand beach which forms the Saal Diego Bay, opposite town, 4 Nov. 1880, Engelmann (M); Whitewater Desert near San Gorgonio Pass, 10 Nov. 1880, Engelmann (М); Whitewater Pass, near Palm Springs, March 1927; Epling (М); Box Canyon, San Diego Co., 4 April 1932, Epling $ Robison (М, СА, 8); Cuyama ER Kern Co., 13 April 1935, Esau (CA); head of Cuyama Valley near Kern Co. line, San Luis Obispo Co., 30 March 1935, Ferris 9140 (СА, 8); in wash near Little E rds Creek, 25 miles from South Dos Palos on the AER road, Fresno Co., 7 April 1938, Ferris 6953 (P, 8); Mohave River bed at Daggett, San Bernardino Co., 14 June 1930, Ferris 8012 (S); pass in Sheep Hole Mts. be- tween Amboy and Dale P. O., San Bernardino Co., 25 April 1932, Ferris $ Baciga- lupi 8128 (P, S) ; wash, west end of Sheep Hole Mts., San Bernardino Co., 24 April 1932, Fosberg 7951 (M); Round Granite Hill near the Narrows, San Diego Co., 14 Nov. 1935, Gander 2955 (SD) ; San Luis Rey Valley, near Rancho San Luis Rey, San Diego Co., 21 Jan. 1937, Gander 3028 (SD); along Coyote Creek, about 3 miles southeast of Lone Palm, north end of Borego Valley, San Diego Co., 6 Mareh 1935, Gander 13454 (SD); ШЫ Peak, Riverside Co., 2 May 1905, Hall 5979 (5); Palm Springs, Feb. 1926, Hart (CA); near Oil City, Kern Co., 22 April 1905, Heller 7743 (G, М, 8); зА Island, San Diego Co., July 1902, Herre (P); gravelly soil, San Felipe Wash, half way between байа Valley and Yaqui Well, western Colorado Desert, San Diego Co., 26 Nov. 1927, Howell 3247 (CA); sandy soil, east end of Morongo Valley, south Mojave Desert, alt. 90 m., San Bernardino Со., 11 Магеһ 1928, Howell 3409 (СА, 8); Barstow, Mohave Desert, alt. 700 m., June 1912, Jepson 4784 (S); San Diego, 16 March 1882, Jones 3076 (CA, M, P, 8); Palm Spring, alt. 61 m., 10 May 1903, Jones (CA, P, 5); Bakersfield, alt. 305 m., 28 May 1903, Jones (P у; Funereal Mts., Death Valley, 10 April 1907, Jone Be Barstow, 18 March 1924, Jones (8); old Woman Mts., eastern Mohave р 13 Мау 1926, Jones (P, S); Big Panoche Pass, 12 miles east of Llanada, San Benito Co., 27 inm 1932, Keck 1833 (CA, 8); Cuyana Valley, on Ozena road, 3 miles from Santa Maria-Maricopa road, Santa Barbara Co., 6 Мау 1933, Keck 2248 (CA, P, 8); south of Bakersfield, March 1925, McCalla (CA); Morongo Valley, Riverside Co., 20 March 1936, MacFadden 14475 (CA); Jacumba-Laguna Mts., alt. 760 m., 9 July 1916, McGregor 138 (S) ; near Jacumba, 27 June 1925, McMinn 1431 (S); Jaeumba Hot Springs, near Monument No. 233, 29 May 1894, Mearns 3332 (G, M, S, US); Mountain Springs, 10 May 1894, Mearns 3024 (8); vieinity of Monument 258 P, International Boundary, 15 July 1894, Mearns 3923 (8); Ja- cumba Hot Springs, 24 Мау 1894, Mearns $ Schoenfeldt 3260 (СА, 8, US); dry sandy wash 10 miles west of 29 Palms, alt. 1060 m., 1 May 1921, Munz 4548 (P); dry slope near Cottonwood Creek and below Barrett Dam, San Diego Со., 10 May 1924, Munz 8026 (С, Р); sandy wash, ноғ Mts., southern Mohave Desert, alt. 1060 m., 8 April 1935, Munz 13805 (P, 8); 566, Mason Valley, eastern San Diego Co., 30 April 1932, Munz $ Hitchcock pH 12073 (M, P); dry тоеку mesa between Whitewater and Mission Creek, Colorado Desert, 7 May 1922, Munz 4 [Vor. 26 398 ANNALS OF THE MISSOURI BOTANICAL GARDEN Johnston 5286 (P); mountains near Campo, San Diego Co., April 1889, Orcutt (Buf, G TYPE, M) ; San Diego, southern part of San Diego Co., June 365 (Buf, G, M); Whitewater, March 1881, Parish $ Parish 653, 1158 (М, 8); Kern River, 1881, Parry (M); sandspit i api San Diego, 17 Mareh 1882, Parry (M); San Diego, April 1882, Parry (M); Colorado Desert, 6 Dec. 1881, Pringle (M); in sand between desert p Мокен in gin alt. 790 m., San Diego Co., 2 Мау 1918, Spencer 807 (СА, 6, P); Coronado Beach, San Diego Co., July 1895, Stokes (S); Panoche, April 1930, Van Dyke (CA); 29 Palms Canyon, Riverside Co., 18 March 1937, Winblad (CA); 4% miles east of Campo, alt. 760 m., on the road to Jacumba, San Diego Co., 27 May 1931, Wolf 2146 (P, S); Colorado Desert, March 1881, Wright 188 (G). BAJA CALIFORNIA: adobe hillside, Refugio Ranch, alt. 620 m., 28 March 1925, Ballon (P); near Enseíiada, 9 Sept. 1923, Eastwood 12358 (CA); dunes and sandy slopes, San Quintin, 5 -— "ie Epling $ Stewart (5); in wash, Santo Tomas Valley at Santo Tomas, 1 March 1934, Ferris ф Bacigalupi 8502 (P, S, US); Jacumba, 2800 ft., 9 July 1922, ‘Fisher 87 (US); dry hills southwest of Valle Re- dondo, 30 May 1932, Fosberg 8381 (M, P, 8); San Jose, Tecate, 27 Nov. 1922, Gallegos 1355 (US); La Huerta at west base of Hanson-Laguna Mts., alt. 850 m., 2 June 1905, Goldman 1127 (US); Trinidad Valley, northwest base of San Pedro Martir Mts., alt. 820 m., 4 July 1905, Goldman 1196 (US); San Matias Pass near Diablito Spring, Valle p" Trinidad, 26 March 1936, Harbison 14851 (S); near Santo Tomas, March 1935, Harvey 535 (08); hills and bluffs near ocean, Епвейада, 7 April 1921, Johnston 3020 (СА, 9, US); Colnet, 15 April 1925, Jones (Р); San Quintin Bay, 7 June 1925, Mason 2058, 2059 (CA, US); San Ysidro Ranch, 2 July 1894, Mearns 3864 (US); about rocks, 50 miles southeast of Tecate, 13 April 1925, Митг 9567 (P); dry rocky slope 50 miles southeast of Tecate, alt. 1375 m., 13 May 1925, Munz 9570 (P); Епвейада, 28 Feb. 1906, Nelson 4: Goldman 7548 (US); San Selmo, Encinada district, June 1928, Үш ег-Сот (СА); San Rafael Valley, 18 March 1885, Orcutt 1271 (C, M); hillside ten miles south of Ensefiada, 24 March 1937, Purer 2127 (M); mountain pass 15 miles south of El Marmol, 2 Feb. 1929, Reed 6215 (P); wash 2 miles north of Socorro, 4 Feb. 1929, Reed 6320 (P); San Ysidro, 28 June 1894, — 3805 (US); south slope, 8 miles from Rosario on road to El Marmol, 4 Mar 930, Wiggins 4340 (S); in wash, 10 miles from El Marmol, 6 March 1930, vasti 4379 (S); coastal slope 3—4 kilometers north of Ensefiada, 12 Sept. 1929, Wiggins $ Gillespie 4016 (СА, G, M, P, S, US); on and adjacent slopes, 15-90 miles east of Ensefiada on road to Ojos Negros, ^ p 1929, Wiggins $ Gillespie 4062 (СА, 8); juniper-covered slopes in vicinity of Ojos Negros, 15 Sept. 1929, Wiggins $ Gillespie 4085 (ОА, G; M, P, 8, US). E. californica may be readily distinguished from the other species with ternate leaf arrangement by the browned and thickened leaves of the older stems. 7T. Ephedra aspera Engelm. ex Wats. in Proc. Am. Acad. 18: 157. 1883. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 399 E. peninsularis Johnston in Univ. Calif. Pub. Bot. 7: 437. 1922. E. Reedii Cory in Rhodora 40: 216. 1938. Erect dioecious shrub, 0.25-1.25 m. high; branches rigid, firm, terete, up to 3 mm. thick, opposite or whorled at the nodes, angle of divergence about 35 degrees; internodes 1-5.5 cm. long; young stems pale to dark green, strongly asperous to smooth and glaucous, with numerous small longitudinal fur- rows, becoming yellow; bark of older stems cinereous, cracked and fissured; terminal buds obtuse-conical; leaves opposite, very rarely ternately whorled, 1-2.5 mm. long, obtusely tipped from a dorso-median thickening, connate for one-half to seven eighths their length; sheath splitting but the parts subpersist- ent; staminate splkes paired, rarely solitary or whorled, at the nodes of the young branches, obovate, 4—7 mm. long, sessile, or rarely short-pedunculate, bracts opposite, in 6-10 whorls, obovate, 3 mm. long, 2 mm. broad, membranaceous, yellow to red-brown, the lower whorl empty ; perianth slightly exceeding the subtending bract; staminal column 4-5 mm. long, one-third exserted, with 4—6 sessile or very short-stipitate anthers; ovu- late spikes paired, occasionally solitary, or whorled at the nodes of the young branches, ovate, 6-10 mm. long, sessile or short- and scaly-pedunculate, bracts opposite, in 5-7 whorls, orbieular, 2-5 mm. long, 2-5 mm. broad, thickened, red-brown, margins membranaceous ; seed solitary, in cross-section circu- lar to slightly trigonal, with a minute indentation at the tip be- tween the angles, smooth to slightly roughened, light brown to chestnut, 5-8 mm. long, 2,5-4 mm. broad, exceeding by one-third the bracts; tubillus slightly exserted, almost straight, the limb contorted. Distribution: southwestern United States and northern Mexico. SPECIMENS EXAMINED: TEXAS: rocky hills and dry ravines, Frontera, Bigelow 2 (G); Fort Bliss, 16 June 1917, Clemens (CA, P); Marathon, Brewster Co., 20 April 1928, Cory 920 (G); Brewster Co., 21 April 1928, Cory 922 (G); Reagan Canyon, Brewster Co., 22 April 1928, Cory 924 (G); 55.4 miles south of Alpine, Brewster Co., 13 April 1936, Cory 18547 (G) type of E. Reedii; same locality 18548 (TAM) ; 9 miles north of Sander- [Vor. 26 400 ANNALS OF THE MISSOURI BOTANICAL GARDEN son, Terrell Со., 15 April 1936, Cory 18736 (6); along railroad, 8 miles west of Sanderson, Terrell Co., 26 May 1938, Cutler 1846 (M); on talus and summit, Per- simmon Gap, Којо Mts., Brewster Co., 27 May 1938, Cutler 1851 (M); gravel plain, à miles north of Glenn A Brewster Co., 27 May 1938, Cutler 1863-1868 j Co., 29 May 1938, Cutler pee DAN (M); Мед plain, 16 miles north of Presidio, Presidio Co., 31 May 1938, Cutler 1926 (M) ; slopes and summit, Beach Mts., 8 miles north of Van Horn, Culberson Co., 2-3 June 1938, Cutler 1958, 1963, 1964, 1966, 1969 (M); canyons near Devil's River, Valverde Co., 13 Sept. 1900, Eggert (М); stony hills near Van Horn, 12 May 1901, Eggert (M); flats near Van Horn, 12 May us Eggert (M); roeky hills near Van Horn, 9 July 1900, Eggert (M); alt. 100 m., southern Brewster Co., 13 July 1927, Fisher (P); El Paso, 18 April 1884, чий 3726 (CA, Е, NMAM, Р, 8); Indian Hot Springs, 30 April 1930, Jones 25963 (CA, M, P, 8); west of Fort Stockton, 18 April 1931, Jones 28372 (P); top of Organ Mts., Aug. 1900, Lemmon 287 (С); Chisos Mts., Aug. 1935, Marsh 64 (P); Terlingua, | re Co., 16 July 1937, Marsh 103 (F); gravelly mesa north of Chisos Mts., alt. 1065 m., 27 June 1931, Moore $ Steyermark 3258 (СА, G, M, S); pom Mts., 28 June 1931, Mueller 7951 (M); Sierra Blanca, 5 July 1895, Mulford 2 (M); dry rocky ground near mouth of Pecos River, Valverde Co., 24 April 1928, rim 33475 (M); dry rocky and gravelly ground, plains and foot hills of Chisos Mts., 24 May 1928, Palmer 34145 (М); western Texas, 22 Мау 1888, Pringle (В); "on of El Paso, 29 March 1908, Rose 11634 (G); west base of Lone МЕ, Chisos Mts., 21 Feb. 1937, Sperry 558, 559 (US) ; El Paso, 188-, Vasey (F, I, M); Mt. Franklin, 20 March 1932, Whitehouse 8840 (CA, Е); western Texas, to Fron- tera, coll. of 1851, Wright 1883 (M) ; rocky hills near Frontera, 4 May 1852, Wright 273? (а); foothills of Chenate Mts., 9 Sept. 1914, Young 53 (М). EW Mexico: Pino Blanea, south end of Organ Mts., alt. 1500 m., Dona Ana Co., 11 Sept. 1930, Fosberg 83960 (P); foot of cliffs near mouth of North Fork, near Three Forks of Rocky Arroyo, Guadalupe Mts., 28 April 1932, Wilkens 1653 (S); meni 's Gap, Organ Mts., 4 April 1903, Wooton (NMAM NA: Roosevelt Dum, 17 May 1919, Eastwood 8676 (CA); Coyote Pass on “ учан» Kingman to Oatman, 16 May 1931, Eastwood 18425 (CA); Yucca, is бнкы 1884, Jones (Р); near Phoenix, 1880, Lemmon 252 (б, М); ену 1880, mon (M); Coyote Pass, between Kingman and Oatman, 16 с P" 2253 (P); Sierra Tueson, 27 Мау 1884, Pringle 39 (G); ти. L April (8). CALIFORNIA: between Tehachapi and Mojave, 28 June 1908, Abrams $ Mc- Gregor 499 (G) ; eastern base of Coast Range, edge of Colorado Desert, 7 May 1894, earns 2956 (G, M, S) ; Mountain Springs, San Diego Co., 12 May 1894, Mearns & Schoenfeldt 3079 (S, US) ; vieinity of Bonanza King Mine, east slope of Providence ts., Mojave Desert, alt. 900 m., 21-24 May 1920, Munz, Johnston $ Harwood 4029 (P); Valleeito, June 1882, Parish 4- Parish (M). MEXxIco: TAMAULIPAS: mountains near Miquihuana, alt, 2100-2700 m., 10 June 1898, Nel- son 4472 (F, G, US) SAN LUIS POTOSI: Sierra de Guascama, Minas de San Rafael, May 1911, Purpus 5334 (G, M, US). 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 401 UILA: dry valley west of Castanuela, 11 April 1847, Gregg 414 (M); west of clans 1949-49, Gregg 53 in part (G) ; Sierra Madre, 40 miles south of Sal- tillo, July 1880, Palmer 1288 (G, М түре, US); Saltillo ne vieinity, 15-30 April 1898, Palmer 69 (G, M, UC, US); Sierra de Parras, March 1905, Purpus 1102 (F, с, M, Р); rocky slopes of El Puerto de San Lazaro, San Lazaro, Municipio de Cas- tafios, 17 June 1936, Wynd $ Mueller 143 (M, U ZACATECAS: high ridges, Cedros, June 1908, Kirkwood 24 (F, G); hills, Cedros, June 1908, Kirkwood E sede 86 (F, M, US). HUA: Sta. a Mts., 4 June 1885, Pringle 38 (G, M, US); Sta. Eu- зана Mid о. 2. 118 (F, US). BAJA CALIFORNIA: Cedros Island, March-June 1897, Anthony 281 (F, M, S, UC, US); Magdalena Island, 12 Jan. 1889, Brandegee (UC), type of E. peninsularis ; Calamalli, 25 April 1889, Brandegee (UC) ; Cedros Island, 1 April 1897, Brandegee (ОС); near Canyon Diablo, 20 miles east, 1 May 1933, Harvey 588 (US); among loose roeks on an old lava flow, Coronados Island, Gulf of California, 18 May 1921, Johnston 8757 (CA, UC, US); north of Turtle Bay, 2 June 1925, Mason 1976, 1977 (СА, Е, US); Cedros Island, 3 June 1925, Mason 2021 (US); north end of Cedros Island, ji bis 1925, Mason 2021а (СА, US); Cedros Island, 18-20 March 1889, Palmer 695 (US); Bay of San Bartolome, 27 April 1889, Pond (US); roeky soil near ЫП, alt. 450 m., Jan.—March 1898, Purpus 6 (Е, S, UC, US); Cape re- gion, near Las Animas, Tani -Магеһ 1901, Purpus 269 (UC); Cedros Island, 11 March 1911, Rose 16140 (US); San Bartolome Bay, 14 March 1911, Rose 16236 (US); 20 miles east of Rosario, 8 Feb. 1935, Shreve 6842 (F). Although the type description states: ‘е seed in pairs,"' all the specimens on the type sheet have the seeds solitary within the strobilus. The strobili, however, are paired at the nodes, and a note on Palmer 69, ‘‘the female plant has a few very dry seeds attached,’’ indicates that the term ‘‘seed’’ was used for the entire strobilus. 8. Ephedra fasciculata A. Nelson in Am. Jour. Bot. 21: 573. 935 Dioecious shrub, often prostrate, 0.25-1 m. high; branches flexuous, solid, terete, up to 3.5 mm. thick, opposite or whorled at the nodes, angle of divergence from the main stem about 35 degrees ; internodes 1-5 cm. long; young stems pale green, very slightly asperous to smooth and glaucous, with small longi- tudinal furrows, becoming yellowed; bark cinereous, cracked and fissured; terminal buds 1-3 mm. long, obtusely conical; leaves opposite, 1-3 mm. long, obtusely tipped from a barely perceptible dorso-median thickening, connate for two-thirds to three-fourths their length at first, later splitting; sheath [Vor. 26 402 ANNALS OF THE MISSOURI BOTANICAL GARDEN hyaline, white, subpersistent; staminate spikes paired or sev- eral at the nodes of the young branches, narrowly elliptic, 4-8 mm. long, sessile, Вгасів opposite, slightly connate, in 4-8 whorls, obovate, 2-3 mm. long, 2 mm. broad, membranaceous, light yellow, the lower whorls empty; perianth exceeding the subtending bract ; staminal column 3-9 mm. long, one-fourth to three-fourths exserted, with 6-10 sessile or very short-stipitate anthers; ovulate spikes solitary or several at the nodes of the young branches, elliptie, 6-13 mm. long, sessile or short-pedun- eulate, braets opposite, in 4-7 whorls, slightly connate at the base, ӨШ, 3-1 mm. long, 2-4 mm. broad, margins hyaline, the back slightly thickened and light brown to green; seed usu- ally solitary, in cross-section almost circular, with numerous longitudinal furrows, light brown, 8-13 mm. long, 3-5 mm. in diameter, one-third to one-half exceeding the bracts; tubillus straight, barely exserted, the ligulate limb bent and slightly contorted. Distribution: Arizona and southern California. SPECIMENS EXAMINED: ARIZONA: Pinal Mts., 18 May 1929, Eastwood 17314 (CA); Phoenix, alt. 300 m., 6 Мау 1903, Jones (P); Sierra Estrella, 13 April 1931, Kearney $ Peebles 7748, 7759 (P); Tule Tank, Yuma Co., 23 March 1935, Kearney $ Peebles 10897 (Ру id slope, trail from Colorado River to Rampart Cave, Lower Grand Canyon, Mo- e Со., 16 June 1937, Милг 14983 (P); dry sand banks, Phoenix, 9 May 1925 тарды 10286 (R TYPE, M, S) ; rocky slopes, vicinity of Canyon Lake, fad Trail, 1 Мау 1935, Nelson § Nelson 1716 (M). CALIFORNIA: Kelso, Mohave Desert, alt. 900 m., 2 May 1906, Jones (Р); canyon near Agua Caliente, April 1882, Parish % Parish 1238 (G, I, M, 8). 9. Ephedra Clokeyi Cutler,?' n. sp. Erect dioecious shrub, 0.5-1 m. high; branches rigid, solid, terete, up to 3.5 mm. thick, opposite or whorled at the nodes, angle of divergence with the main stem about 40 degrees; inter- ” Ephedra Clokeyi Cutler, sp. nov.; frutex erectus, dioieeus, 0.5-1 m. altus; ramulis rigidis, solidis, teretibus, usque ad 3.5 mm. in diametro, ad nodos |: vel vertieillatis, angulo declinationis circiter 40°; internodiis 9-5 . longis; caulibus juventate pallide viridibus, parce scabris vel laevibus et еее tenuis- sime striatis, deinde lutescentibus; rhytidoma cinerea, rimosa, sulcata; gemmis terminalibus 2-3 mm. longis, obtuso-conicis; foliis oppositi is, 1-3 mm. longis, ad 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 403 nodes 2—5 em. long; young stems pale green, slightly asperous to smooth and glaucous, with numerous small longitudinal fur- rows, becoming yellowed; bark cinereous, cracked and fissured ; terminal buds 2-3 mm. long, obtuse-conical; leaves opposite, 1-3 mm. long, obtusely tipped from a dorso-median thickening, connate for one-half to seven eighths their length at first, later split; sheath membranaceous, deciduous; staminate spikes paired or numerous at the nodes of the young branches, obo- vate, 4-7 mm. long, sessile or very short-pedunculate, bracts opposite, slightly connate, in 5-8 whorls, obovate, 2-3 mm. long, 2 mm. broad, membranaceous, light yellow to light brown, the lower whorls empty; perianth exceeding the subtending braet ; staminal column 3-6 mm. long, one-fourth to two-thirds ex- serted, with 6-9 sessile or very short-stipitate anthers ; ovulate spikes paired or numerous at the nodes of the young branches, obovate, 6-10 mm. long, sessile or short-pedunculate, bracts op- posite, in 5-8 whorls, slightly connate at the base, broadly elliptic, 3-5 mm. long, 2-4 mm. broad, margins hyaline, the back slightly thickened, light brown to green; seed usually solitary, in cross-section almost circular, with numerous longi- tudinal furrows, light brown, 5-8 mm. long, 2.8-4 mm. broad; tubillus straight, slightly exserted, the ligulate limb bent and contorted. Distribution: southern Utah, Arizona, Nevada and southern California. apicem obtusis ex dorso-medio crassificatione, primo ad 12-7 longitudinis con- natis, deinde diffisis; vagina membranacea, decidua; spieis stamineis paribus vel multis ad nodos ramulorum novorum, obovatis, 4-7 mm. longis, sessilibus vel brevi- peduneulatis, braeteis he Linie parce connatis, in 5-8 vertieillis, obovatis, 2-3 mm longis, 2 mm. latis, mbranaceis, pallide luteis vel pallide fulvis, Каган verticillis inferioribus. vacuis; perianthis bracteas subtendentes superantibus; г 881 е 8-6 mm. baih brevissime stipitatis; dil femineis paribus vel multis ad nodos ramulorum novorum, obovatis, 6-10 m 2 sessilibus vel brevi-peduneulatis, bracteis op- positis, in verticillis 5-8, ad basem parce connatis, late elliptieis, 3-5 mm. longis, mm. latis, marginibus hyalinis, dorso paree ce palide fulvis vel viridibus; seminibus plerumque solitariis, in seetione transverse Ж.” "m multis longitudinalibus, pallide fulvis, 5-8 mm. lc. mm. tubillo recto, leviter exserto, limbo ligulato eurvato et contorto. [Vor. 26 404 ANNALS OF THE MISSOURI BOTANICAL GARDEN LÀ EXAMINE NA: eanyon cadi Antler, Mohave Co., 8 April 1928, Braem (5); Hermit Trad), бай Canyon, 9 April 1917, Eastwood 5965 (CA); Hermit Creek, Grand Canyon, 10 April 1917, Eastwood 6004a, 6017 (СА); Grand Canyon of the Colorado, 11 April 1917, Eastwood 6032, 6040 ет ); Hermit Trail, 12 April 1917, Eastwood 6057 (CA); Bright Angel Trail, Grand Canyon, 14 April 1917, Eastwood 6100 (CA); Roosevelt Dam, 19 April ves Eastwood 6212 (СА); Hieroglyphie Canyon, Salt River Mts., alt. 500 m., Maricopa Co., 24 March 1932, Gillespie 5529 (P, 8, UC); near Oatman, 23 March 1931, Harrison 4 Kearney ds (F); Chimehuevis, alt. 1400 m., 21 April 1903, Jones (P); Hammock, 17 Mareh 1932, Jones 29008 (M, P); кімде the lava mM Dunean, 22 Магеһ 1930, vane 11280a (G, 8). UTAH: St. George, 2 April 1880, Jones (M, S); southern Utah, 1874, Parry 249 (F, G, I, M); valley of the Virgen near St. George, 1874, Parry 249 (G); southern Utah, 1874, Parry 251 in part (G, M). МЕУАРА: gravel, Mica Spring, alt. 1200 m., 14 April 1894, Jones 5062 (G, М, P, US); Logan, 5 May 1909, Kennedy 1841 (Т, 6, Б); rocky slopes of small gully, Frenehman Mt., northeast of Las Vegas, 30 May 1933, Munz 12955 (P). CALIFORNIA: rocky slope and wash, desert, Cottonwood Springs, Riverside Co., 17 April 1935, Clokey 6510, 6511, 6512 (Clo, М); among rocks, hillside and wash, desert, Cottonwood Springs, Riverside Со., 17 April 1935, Clokey 6513 (Clo, M TYPE); rocky slopes and wash in desert, Cottonwood Springs, 17 April 1935, Clokey 6514 (Clo, М); gravelly hills and ravines, Fort Mojave, 25 Feb. 1861, Cooper (М); Box Canyon, San Diego Co., April 1932, Epling 4$ Robison (СА, M, 8); at bridge in Sentenae Canyon, San Diego Со., 7 Магеһ 1935, Gander 138.12 (SD); Borego Palm Canyon, San Diego Co., 14 igi 1936, бекіне 1275 (SD); desert along mountains, alt. 300—770 m., Pim Canyon, Riverside Co., 4 April 1917, Johnston (P, 6); Imperial Valley, 28 Feb. 1924, Jones (P); walls of Box Canyon, western qp Desert, eastern San Diego Co., 2 April 1932, Munz $ Hitchcock 12047 (Е, Р}; E 277 slopes, vieinity of Corn у nuo о walla Mts., Colorado a alt. 460 m., 9-12 April 1922, Munz $ Keck 9 (P); Mountain Springs, 6 April = Ad 9070 (S); desert sand, "radi: phe dia San Diego Co., 26 March 1917, Spencer 206 (С, Р); on highway 80, Mountain Springs grade, about 1 mile east of Mountain Springs service station, Imperial Co., western edge Imperial td (Colorado Desert), alt. 250-270 m., 1 Мау 1938, Whitaker (M). This species has been included under Е. nevadensis Wats. by most botanists but differs from it in having a solitary seed within the strobilus in contrast to the paired seeds of Е. nevadensis. 10. Ephedra nevadensis Watson in Proc. Am. Acad. 14: 298. 1879. E. antisyphilitica Wats. іп U. S. Geol. Surv. Fortieth Par- allel [Bot. King’s Exp.] 5: 329, pl. 39. 1871, not C. A. Mey. Е. antisyphilitica var. pedunculata Watson, loc. cit. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 405 E. nevadensis Wats. subvar. paucibracteata Stapf in Denkschr. К. Akad. Wiss. Wien 562: 83. 1889. Erect dioecious shrub, 0.25-1.25 m. high; branches rigid to flexuous, solid, terete, up to 4 mm. thick, opposite or whorled at the nodes, angle of branch-divergence about 45 degrees; internodes 1.5-6 em. long; young stems pale green, glaucous, almost smooth, with shali longitudinal furrows, becoming yel- low, then gray; bark cinereous, fissured; leaves binate, rarely ternate, 2-4 mm., rarely to 8 mm. long, obtusely tipped from a dorso-median thickening, connate for one-half to two-thirds their length, later splitting and falling off; staminate spikes solitary to several at the nodes of the young branches, elliptic, 4-8 mm. long, sessile to short-pedunculate, bracts opposite, in 5-9 whorls, obovate, 3-4 mm. long, 2-3 mm. broad, membrana- ceous, yellow to light brown, the lower whorl empty ; perianth slightly exceeding the subtending bracts; staminal column 3- 5 mm. long, one-quarter to one-half exserted, with 6-9 sessile to short-stipitate anthers ; ovulate spikes solitary to several at the nodes of the young branches, suborbicular, 5-11 mm. long, borne on an almost naked 1-50-mm. long peduncle, bracts bi- nate, in 3-5 whorls, suborbicular, connate at the base, 4-8 mm. long, 3—6 mm. broad, herbaceous, light brown to yellow-green, occasionally tinged with pink; seeds paired, rarely solitary, brown, smooth, 6-9 mm. long, 2-4 mm. broad, equaling or ex- ceeding the bracts; tubillus moderately exserted, slightly re- curved, barely contorted. Distribution: Utah, western Arizona, Nevada, Oregon and California. SPECIMENS EXAMINED ARIZONA ; Kingman, 1 14 April 1931, Eastwood 18007 (CA); Hackberry, 24 May 1884, у (P); Camp Lowell, 1880, 27% 251 (6). UTAH: ылы, of St. George, alt. „ Washington Co., 3 June 1929, Cot- tam 3 (BYU, Р); sandy soil, Santa he нерді», alt. 900 m., Washington Co., 24 April 1930, doe 4701 (BYU); dry clay loam, roadside, 6 miles west of Hinck- ley, alt. 1520 m., Millard Со., 9 May 1935, Harrison 6305, 6206 (BYU); Santa Clara, 8 April 1880, ie die St. George, 2 April 1880, Jones (M, S) ; Frisco, 225 miles southwest of Salt Lake, 22 April 1880, Jones (M); Milford, 17 June 1880, Jones (P); Milford, 1% June 1880, Jones (P); Milford, 22 June 1880, Jones 1802 [Vor. 26 406 ANNALS OF THE MISSOURI BOTANICAL GARDEN in part (CA) ; gravel, Marysvale, alt. 1820 m., 4 June 1894, Jones 5388ag (CA, d. ; Duteh Mt., alt. 1620 m., Tooele Co., 15 June 1900, Jones (P); Vermilion, 4 Jun 1901, Jones (Р); Price Valley, alt. 1590 m., 3 July 1903, Jones (P); Leam bine alt. 1520 m., 8 May 1911, Jones (СА, 8); near Salt Lake, 0900 (UI); roeky slopes above publie eamp, Zion National Park, 2 April 1934, Maguire, Maguire d Maguire 4723 (M); bluffs near Priee, alt. 1800 m., 11 June 1900, gena (8); slopes and mesas west of St. George, 6 Мау 1919, Tidestrom 9303 (M, G, US). NEVADA: gravelly wash, Kyle Canyon, Charleston Mts., 1350 m., Cla e Co., 29 April 1938, Clokey 2465 (Clo, M); near Pyramid Lake, 24 June 1927, Eastwood (М ТҮРЕ of E. antisyphilitica var. pedunculata, G) ; Columbus, alt. 1520 m., 20 Мау 1897, Jones (P); Good Springs, 1 May 1905, Jones (СА); Big Pine, 3 June 1924, Jones (P); Pyramid Lake, Washoe Co., 19 May = Kennedy 999 (M); Pyramid Lake, alt. 1310 m., 1 June 1913, Kinnell 1988 (I, M, S); west shore of mid Lake, May 1879, Lemmon (G, M) ; shad-scale desert, 17 miles north of Baker, White Pine Co., 16 June 1933, Maguire $ Becraft 2479 (G, M, P); Atlatl Park, Valley of Fire, Clark Co., 6 April 1934, Maguire, Maguire ф Maguire 4717 (M); in desert pavement, 14 ds north of Glendale, Lineoln Co., 6 April 1934, к Maguire 4 Maguire 4719 (M); Corey Canyon, Wassuk Mts., alt. 1850 m., near Hawthorne, 27 June 1919, Tidestrom 10099 (M, US); Smoky Valley, alt. 1678 m., July 1868, Watson 1108 in part (G Tv OREGON: very dry slopes га lower Pueblo Mts., above Catlow's талеһ, Harney Co., 4 July 1927, Honderson 8670 (CA). CALIFORNIA: desert slopes, Jacumba, San Diego Co., 31 May 1903, Abrams 3676 (G, M, P); Great Falls Canyon, Argus Mts., вито Desert, 18 April 1930, Bailey "n Robison (CA, М); sandy soil, Walker Pass, Piute Mts., alt. 1200 m., Kern Co., 24 April 1932, Benson 3446 (S); about 60 miles north of Los Angeles, June 1890, Coquillett (M, US); Mojave, Kern Co., 13 May 1913, Eastwood 3220 (СА); between Jaeumba and Mountain Springs, San Diego Co., 24 April 1920, Eastwood 9522 (CA); between Victorville and Lucerne Valley, баз Bernardino Co., 29 April 1932, Eastwood 18716 (СА); on road to Barstow from Las Vegas, San Bernardino Co., 30 April 1932, Eastwood 18766, 18791 (CA); Acton, Los poem eles Co., June 1902, Elmer 3599 (M); Palmdale, 24 April 1926, Epling (M); in vacant lot, Lan- easter, Los Angeles Co., 12 June 1918, Ferris 909 (S); low desert hills, on shore of Owen's Lake near Gowan, Inyo Co., 11 July 1918, Ferris 1347 (8); oceasional on rocky slopes, eastern base of Hackberry Mt., near Goffs-Lanfair road, alt. 1100 m., San Bernardino Co., 24 April 1928, Ferris 7283 (S); yucca-juniper forest, 23 miles west of Lancaster in Antelope Valley, Kern Co., 3 May 1929, Ferris 7702 (P, 8); in yucca grove on Tehachapi road, 6 miles from Менла, 17-24 March 1924, Ferris, Scott $ Bacigalupi 3874 (S); hills near Victorville, alt. 1050 m., San Bernardino Co., May 1905, Hall 6212 (S); between Lancaster and Victorville 27 рыч 1930, Hart (CA); Randsburg, Kern Co., 14 April 1905, Heller 7703 (M); sandy soil, open desert, Mojave Desert, alt. 900 m., 9 miles southeast of Victorville, San Be nardino Co., 11 June 1927, Howell tias (CA); ; sandy soll, half way between Victor- ville and Hesperia, Мык Desert, alt. 900 m., San Bernardino Co., 12 June 1927, Howell 2529 (CA); Mohave Desert, near Barstow, alt. 800 m., 8 June 1912, Jepson 4831 (S); hillside, Vietorville, 15 May 1920, Johnston (P); in sunny, hot, sandy stretches, Deadman Point, Mohave Desert, alt. 900 m., 10 May 1920, Johnston (P); 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 407 Bishop, Owen's Valley, alt. 1920 m., 15 May 1897, Jones (M, P); Vietor, alt. 800 m., 17 May 1903, Jones (P); west slope of Walker Pass, alt. 1370 m., Kern Co., 5 May 1932, Munz ed (M, P); Mohave ёо, southeast T 1 June 1876, Palmer 524 (G, M, co-types of E. sis su aucibracteata) ; Warren’s Well, San Баай Mts., alt. 1060 m m., pr 5 June 1894, ‘Parish sore (M); Hesperia, Mojave Desert, 30 May 1918, Parish 11841 (M, P, 5); mountains of the Mojave Desert, March 1882, Parish 4 Parish 1368 (M); Cushenberry Springs, Mojave Desert, Мау 1882, Parish $ Parish 1569 (5); Mojave Desert, May 1882, Parish $ Parish 1369 (G, M) ; Mohave Desert, 31 May 1882, Pringle (M) ; sandy soil, Argus Mts., alt. 1200-1500 m., April-Sept. 1897, Purpus 5032 (G, M); Hesperia, April 1892, Trelease (M). The type collection of E. nevadensis consists of two species, staminate material of what is now considered E. nevadensis, and ovulate material of E. viridis. 'The description by Watson stressed the staminate material and mentioned it first and as Californian specimens of E. viridis were cited as being peculiar and perhaps distinct, this is interpreted as leaving the stami- nate material of Watson’s collection as the type. Other mate- rial cited in the original description is that of Cooper from Fort Mohave, California (Е. Clokeyi) ; of Gregg from northern Mex- ico (no number is given but this is probably E. aspera); and a form from New Mexico with no collector or locality given but probably referring to Wright's or Bigelow's collection of E. aspera and stated to differ in having very short peduncles and solitary fruits. The form described as Е. Clokeyi has been included under E. nevadensis by most contemporary botanists but is distinet, having only one seed surrounded by membrana- сеопв һгасів as opposed to the paired seeds surrounded by herbaceous braets in E. nevadensis. This species varies greatly, the southern forms mostly smaller and dark-stemmed ; the northern forms with large and almost herbaceous, light-colored stems. The very young shoots are frequently marked by a ternate arrangement of some whorls of leaves. 10a. Ephedra nevadensis forma rosea Си ег,?8 n. f. Differs from the species in having roseate bracts, seeds less than 5.5 mm. long. з Ephedra nevadensis forma rosea Cutler, f. nov., a specie differt braeteis roseis, seminibus usque ad 5.5 mm, longis. [Vor. 26 408 ANNALS OF THE MISSOURI BOTANICAL GARDEN Distribution: western Nevada and adjacent California. SPECIMENS EXAMINED: МЕУАРА: near Pyramid Lake, 24 June 1927, Eastwood 14744 (СА TYPE). CALIFORNIA: Willow Springs, Kern Co., 1 July 1905, Grinnell 436 (US). 11. Ephedra viridis Coville in Contrib. U. S. Nat. Herb. 4: 220. 1893. E. nevadensis var. viridis (Coville) Jones in Proc. Calif. Acad. II, 5: 726. 1895. E. nevadensis subvar. pluribracteata Stapf in Denkschr. K. Akad. Wiss. Wien 562: 83. 1889. Erect dioecious shrub, 0.5-1 m. high; branches rigid, firm, terete, up to 3 mm. thick, opposite or numerous at the nodes, angle of divergence about 33 degrees; internodes 1-4.5 cm. long; young stems bright-green to yellow-green, later yel- lowed; bark of older stems cinereous, cracked and fissured; terminal buds 1-2 mm. long, obtuse-conical; leaves opposite, 1.5-4 mm. long, obtusely to setaceously tipped from a dorso- median thickening, connate for one-third to three-fourths their length, sheath membranaceous-margined, soon falling to leave the thickened and persistent brown base; staminate spikes paired or numerous at the nodes of the young branches, obo- vate, 5-7 mm. long, sessile, bracts opposite, barely connate at the base, in 6-10 whorls, ovate, 2-4 mm. long, 2-3 mm. broad, membranaceous, light yellow, slightly reddened, the lower whorl empty; perianth slightly exceeding the subtending bract ; staminal column 2-4 mm. long, one-fourth to one-half exserted, with 5-8 sessile or almost sessile anthers; ovulate spikes op- posite or several at the nodes of the young branches, obovate, 6-10 mm. long, sessile or on short, scaly peduncles, bracts ор- posite, in 4-8 whorls, ovate, 4-7 mm. long, 2-4 mm. broad; seeds paired, light brown to brown, trigonal, smooth, 5-8 mm. long, usually exceeding the bracts by one-fourth; tubillus straight or slightly bent, exserted, the ligulate limb slightly contorted and meagerly recurved. Distribution: western Colorado, Utah, western Arizona, Ne- vada and California. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 409 SPECIMENS EXAMINED: CoLoRADO: slopes, upper "s area, Uncompahgre Plateau, west of Delta, 6 June 1909, Tidestrom 2170 (U ARIZ below Beaver te ЕТА Mohave Co., 11 May 1938, Barkley 3333 (M); pim of Walnut Creek, alt. 2000 m., 1 July 1909, Burrall у č ; near rim of Grand Canyon, east of Point Hope, 3 April 1918, Collins (G); dry flats, Lee's Ferry, alt. 1050 m., Coconino Co., 6 July 1927, Cottam 2610 (BYUY; “Bright Angel Trail, Grand саг. WEN Bot: 1913, ird P (CA); Grand View Trail, Grand Canyon, 16 June 1916, үа 571 9 (CA); Hermit Trail, Grand Canyon, 18 June 1916, Hastwood 5872 (CA); eb Creek, 10 April 1917, East- wood 6026 (CA); trail to Monument Creek, 11 April 1917, Eastwood 6033, 6042 (CA); Bright Angel Trail, Grand Canyon, 14 April 1917, Eastwood 6109 (СА); north rim, Grand Canyon, 22 June 1933, Eastwood § Howell 934 (CA); mesa be- tween Fredonia and Ryan City, alt. 2000 m., Coeonino Co., 8 July 1914, Eggleston 10191 (P); Bright Angel Trail, Grand Canyon, alt. 1220 m., 31 May 1913, Gold- man 2075 (US); Bright Angel Trail, alt. 2080 m., 19 Aug. 1913, Goldman 2210 (US); near the hotel, Grand Canyon, 25 April 1905, Goulding (5); Grand Canyon, 24 May 1903, Grant 5644 (CA, M, P, 8); canyon 2 miles below Pagumpa, alt. 1220 m., 21 April 1894, Jones 5089r (P); mesa below Buckskin Mts., alt. 2120 m., 21 Sept. 1894, Jones 6063q (P); Chloride, alt. 1370 m., 14 April 1903, Jones (P); j Chimehuevis, alt. 980 m., 21 April 1903, Jones (P); Peach Springs, 14 June 1929, Jones (P); Valentine, pe Co., 17 April 1934, Kearney 4: Peebles 11107 (US); Walnut Canyon, 19 May 1891, MacDougall 100 (US); near Canyon Diablo, Coconino Co., 18 May md чекди #2 285 (P); Bright Angel Trail, Grand Canyon, 6 May 1917, Meiere (CA); e of Walnut Creek, Coconino National Forest and vieinity, 1 July 1929, su s An (US); near Flagstaff, June 1900, Purpus 7087 (US); Holbrook, 6 May 1899, Zuck (M, US TAH: west ridge of Virgen River, Zion National Park, 9 May 1938, Barkley 8115 (M); hillsides, Hunt’s ranch, alt. 1800 m., Washington Co., 26 Aug. 1927, Cottam 1189 (BYU); crevices of lava rock, Yee, alt. 1750 m. ‚йада Со., 21 June 1928, Cottam 3368 (BYU); mountain side, alt. 2000 m., Apex Mine, Washing ton Co., 4 June 1929, Cottam 4115 (BYU, P); east of Escalante, alt. 1680 m., 18 June 1929, Cottam 4380 (BYU); cliff, nia of Antelope Springs, alt. 2250 m., .. Mil: lard Co., 19 April 1930, Cottam 4630 (BYU, M); foot of Lady Mt. Trail, Zion Na- tional Park, 19 June 1928, Craig 1450 (P); among rocks ba canyon, 8 miles west of Castle Dale, Emery Co., 25 June 1938, Cutler 2373-2375 (M); canyon walls, 5 miles west of Elberta, Soak Co., 26 June 1938, Cutler 2433-2435 (M); foothills 5 miles northeast of Ephraim, alt. 2000 m., San Pete Co., 20-26 May 1914, Eggleston 10143 Me Dry 2. bd. just above Dr ry Fork bene alt. 2050 m., Uintah Co., 12 Ma мы 3 (M); burned-over north slope of бзш Ridge, нов "id 7 We River, S ы southeast of mouth of Wolf Creek, alt. 2000 m., 1 June , Graham 9073 (M, US); Red Wash, just northwest of mouth of Split Mt. cn above Island Park, alt. 1600 m., Uintah Co., 10 June 1935, Graham 9147 (М, US); on cliff, Cottonwood Creek Canyon, south of Minnie Maud Crock, alt. 1750 m., Carbon Co., 7 July 1935, Graham 9521 (M, US); Diamond Valley, 22 April 1919, Hall 527 (US); near Anderson's raneh, Washington Co., 28 July 1927, Harris N27134 (M); Ephraim Plateau, 4 Aug. 1927, Harris C27713 (M); rocky cliffs, [Vor. 26 410 ANNALS OF THE MISSOURI BOTANICAL GARDEN Desert ce Experiment Station, alt. 1750 m., Millard Co., 11 May 1935, Harrison 63828 (BYU, M) ; moist north slope, Tintie Ма, east of Puis; alt. 2120 m., Juab Co., 22 May. 1938, Harrison 8328, 8229 (BYU i: oe sage-brush slope, Ashley Creek Canyon, about 10 miles northwest of Vernal, alt. 1 m., uly 1933, Hermann 4920 (М); St. George, 2 April 1880, Jones А. pts: Frisco, 22 June 1880, Jones (CA, M, P); Milford, alt. 1520 m., 22 June 1880, Jones 1802 (NMAM, 8, US) ; Dutch Mt., 12 June 1891, Jones (P); re d sand, Belvue, alt. 1100 m., 30 March 1894, Jones 5001% (P); gravel, Diamond Valley, alt. 1370 m., 28 April 1894, Jones 5124 (M, P, US) ; 10 miles below Kanarra, alt. 1370 m., 12 Мау 1894, Jones 52184 (US) ; red sand, Johnson, alt. 1600 m., 23 May 1894, Jones 5289y (P); red sand, Pahria Canyon, alt. 1600 m., 26 May 1894, Jones 5297v (P); gravel, Marvine Lac- eolite, alt. 1800 m., 23 July 1894, ae 566367 (P); Monroe, Sevier Co., alt. 1680 m., 24 May 1899, wor (Р); т Creek, alt. 1800 m., 8 June 1910, Fonas СҰ? айоо Hurrieane eliffs, west exposure, 1 mile east of окей, alt. 1020 m., Wash- ington Co., 1 May 1932, Maguire $ Blood 1277 (P); stony ground, Foe "8 ranch, St. George, 5 Nov. 1922, Nelson 9990 (M, R); St. George, collection of 1876, Parry 251 (а, M, US); Buckskin Mts., Kanab, June 1923, Rodda (CA); canyon near Copper Mines, Beaverdam Mts., 6 May 1919, Tidestrom 9357 (US); dry gumbo hillsides, alt. 1800 m., vicinity of Flaming dongs, Daggett Co., 31 May 1932, Wil- li ). NEVADA: 6 iin east of Reno, 13 May 1929, Canby 173 (P); flat, Kyle Canyon, с дейд Mts., alt. 2100 m., Clark Co., 10 My 1936, Clokey 2027, 7028 (СА, F, М, 8, US) ; дере, Mt. Wheeler, alt. 2300 m., White Pine Co., 20 June 1928, Cottam $300 (BYU); pass north of Olcott Peak, Сейм Mts., alt. 1700 m., Lineoln Co., 6 March 1891, Coville $ Funston = (US); Trail Canyon, White Mts., alt. 2400 m., 14 June 1930, Duran 501 (CA, M, P, 8, US, UW); on road from Reno to Pyra- mid Lake, 24 June 1927, ње 14719 ( (CA); vidis Lake, June 1927, East- wood 14742 (CA); on road to Pyramid Lake from Reno, June 1927, ee 14761 (CA, P); Victory Highway, 5 miles east of Sparks, 8 June 1933, Eastwood $ pig 29 (CA); e e Co., 15 April 1927, Haley (СА); ee alt. 2200 m., Deer Lodge, Lincoln Co., 6 June 1935, Hall (BYU); Pyramid Lake, 28 Mes 1916, Headley 13 (UB); ; Goldfield, alt. 2000 m., 4 June 1912, Heller 10411 (S, US); Reno, 16 May 1899, Hillman (P); dry hills, Hunter's Canyon, vieinity of Reno, alt. 1350—1500 m., 18 July 1913, Hitohooob 518% (US); Austin, 16 June 1882, Jones (P); Rhyolite, alt. 1160 m., 11 April 1907, Jones (M, P); Round Mt., Nye Co., Aug. 1915, Phares Carson T alt. 1400 m., 3 July 1931, Ron (CA) ; dry lakes, Verdi, May-Jun 1880, Sonne 491 (M); сапуоп, Montezuma Mt., west of Goldfield, alt. 2100 m., 4 April 3019, Tidestrom 9771 (M, US); slopes of Sweetwater Mts., near Sweetwater, alt. 2280 m., 1 July 1919, Tidestrom 10200 (US); Smoky Valley, alt. 1675 m., July 1868, Paton 1108 in part (G); hillside мнени Silver City and Dayton, гуана Со., 27 July 1933, Wiggins 6755 (В). CALIFORNIA: rocky hills between Rosamund and Mojave, Kern Со., 30 April 1927, nae 11769 (P, 8); west side, Walker Pass, alt. 1130 m., Kern Co., 1 May 1927, Abrams 11920 (P, 8); Sespe Creek, near Ten Sycamore Flat, alt. 700-770 m., Ventura Co., 9 June 1908, Abrams $ McGregor 174 (US); near the Frazier Borax Mine, Mt. Piss, alt. 1600-1900 m., Ventura Co., 12-14 June 1908, Abrams 4: Mc- mh 217 (S); near Mitehell's Canyon, әнімді Mts., Mojave Desert, Nov. 1935, Alpin (P); granitie soil, arid ridges about 3 miles west of Benton, Mono Co., = 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 411 6 Nov. 1931, Applegate 6904 (S) ; 3-5 miles east of Topaz, Mono Co., 20 May 1915, Bolton (CA); Santa Inez River, March 1861, Brewer 347 (M); 3% miles west of Leevining, alt. 2400 m., Mono Со., 23 Aug. 1933, Clausen 797 (8); hillside, Cayama Valley, alt. 1500 m., Ventura Co., 22 May 1935, Clokey 6516 (Clo, M); just above Crystal Spring, Coso Mts., alt. 1840 m., Inyo Co., 12 June 1891, Coville $ Funston ү К TYPE); Cuddy Canyon, Mt. Pi nos region, 19 June 1896, Dudley 4 Lamb 9 (P) Укан, 15 йу ЧЕ, Epling $ Robison (M); Lone Pine Trail, above fidis Cottonwood Creek, alt. 2000 m., Inyo Co., 23 June 1923, Ferris 3741 (8); northwestern slope of Maturango Bar Argus Mts., Inyo Co., 12 April 1930, Ferris 7857 (S); above old town of Panamint, Surprise Canyon, Panamint Mts., alt. 2250 m., Inyo Co., 12 June 1930, Ferris 7955 (M, S) ; open sandy desert, Haekstaff, Lassen Co., Ferris $ Duthie 4 (8); quartzite slope, Gold Mt., above Baldwin Lake, alt. 2200 m., San Bernardino Co., 19 June 1932, Fosberg 8500 (М); between Susan- ville and Leavitt Lake, Lassen Co., 12 May 1930, Gillespie 9347 (S); Mt. Pinos, Ventura Co., 16 May 1923, Hart (CA); desert slope, from Big Bear region, San Bernardino Co., 4 July 1924, Hart 81 (CA) ; granite sand, mouth of a eanyon about three miles south of Bishop, alt. 1380 m., Inyo Co., 21 May 1906, Heller 8299 (CA, M, S); sandy slopes, Frazier Mt. Park, Pinos region, Kern Co., 25 May 1928, Howell 3824 (CA); rocky slopes, south side of Surprise Canyon near Panamint City, Panamint Mts., Inyo Co., alt. 2400 m., 14 June 1928, Howell 3924 (CA); rocky slope, Kern Canyon, 7 miles above Кет, alt. 830 m., Kern Со., 13 May 1930, Howell 5028 (CA); Rose Mine, San Bernardino Mts., alt. 2120 m., 2 Sept. 1921, Jaeger 1061 (P, S) ; sunny mountain side, Prairie Fork of San Gabriel River, San ntonio Mts., alt. 1530 m., 23 Aug. 1917, Johnston 1721 (P, 8); rocky ground at foot of hill, Deadman Point, alt. 900 m., 16 May 1920, Johnston (P); Needles, 7 May 1884; Jones (P); Cactus Flat in с Canyon, 12 Мау 1926, Jones (Р, 8); DE, San Diego Co., 30 July 1923, Kendall (P); eight miles up Mt. Whit ney Trail from Lone Pine, јачи Lone Pine Creek, alt. 2250 m., Inyo Со., 9 June 1935, Kimber (S); Hot Springs Peak, alt. 1460-2120 m., Teen Co., July 1913, Monnet 839 (CA); dry loose slope, Big Rock Creek, San Gabriel Mts., alt. 1300 m., Los Angeles Co., 27 May 1923, Munz 6876 (Р); dry banks, Seymour Creek, Mt. Pinos, alt. 1900 m., 10 June 1923, Munz 6979 (P); dry slope, Baldwin Lake, San Bernardino Mts., alt. 2120 m., 2 June 1924, Munz 8188 (P); base of cliffs, 5 miles south of Bridgeport, Mono Co., 22 June 1928, Munz 11082 (P); among rocks, Eagle Mts., Colorado Desert, alt. 250 m., 13 April 1921, Munz Фф Keck 4951 (P); near Bishop, Inyo Co., 20 June 1937, Noldke (CA); Rock Spring, Mohave Desert, 14 May 1876, Palmer 525 (M, co-TYPE of E. nevadensis var. pluribracteata) ; Rose Mine, San Bernardino Mts., alt. 1800 m., San Bernardino Co., 17 June 1894, Parish 297 (M, US); summit of Pilot Knob, Mojave Desert, 14 May 1922, Pierson $ Johnston 6510 (P); sandy soil, Argus Mts., April-Sept. 1897, Purpus 5312 (M, US); rocky canyon sides, west slope of Pleasant Canyon, Panamint Range, alt. 800 m., Inyo Со., 30 March 1937, Train (S); 4-5 miles south of Tehachipi, alt. 1525 m., Kern Со. , 17 June 1928, Wolf 2210 (CA, P, S); rocky soil, Leevining Canyon, Sierra Nevada: alt. 2300 m., Mono Co., 5 Nov. 1931, Wolf 2551 (8). Тһе dark and persistent leaf-bases and the sessile or short- peduneulate ovulate strobili readily distinguish this Species from E. nevadensis. Specimens of E. viridis from high alti- [Vor. 26 412 ANNALS OF THE MISSOURI BOTANICAL GARDEN tudes and from the northern portions of the range have darker leaf-bases and more numerous branches but are not sufficiently distinct to separate. 12. Ephedra Coryi Reed in Bull. Torr. Bot. Club 63: 351, figs. 1, 3. 1936. Erect dioecious shrubs, growing from spreading rhizomes, 0.25-1 m. high; branches terete, up to 2.5 mm. thick, opposite or whorled at the nodes, angle of divergence about 22 degrees; internodes 2-4.5 ст. long; young stems almost herbaceous, bright green, slightly asperous, with numerous small longi- tudinal furrows, becoming yellow; bark of older stems red- brown, cracked and fissured irregularly ; terminal buds 1-3 mm. long, obtusely conical; leaves opposite, acutely tipped from a dorso-median thickening, connate for one-third to three-fourths their length; sheath membranaceous-margined, soon falling to leave the brown, thickened and persistent base; staminate spikes paired or numerous at the nodes of the young branches, obovate, 4-7 mm. long, sessile or short-pedunculate, bracts op- posite, slightly connate at the base, in 5-9 whorls, ovate, 2-4 mm. long, 2-3 mm. broad, membranaceous, light yellow, the lower whorl empty; perianth slightly exceeding the subtend- ing bracts ; staminal column 2-4 mm. long, one-fourth exserted, with 5-7 sessile or short-stipitate anthers; ovulate spikes ор- posite or several at the nodes of the young branches, obovate to spherical, 7-15 mm. long, peduncle 3-20 mm. long, with two pairs of bracts, one basal, the other subterminal, bracts ор- posite, in 3-4 whorls, ovate-acute at first, becoming yellow, fleshy and orbicular at maturity ; seeds paired, trigonal, brown to chestnut, smooth, 5—7 mm. long, usually equaling or slightly exceeding the bracts; tubillus straight, slightly exserted, the barely contorted ligulate limb recurved. Distribution: west-central Texas. SPECIMENS EXAMINED: Texas: 1174 miles east of Seminole, Gaines Co., 20 May 1935, Cory 13711 (US); Boll’s ranch, 10 miles southeast of Lubbock, 6 April 1930, Demaree 7475 (G, M, 8); dry prairies near Stanton, Martin Co., 13 June 1900, Eggert (М); sandy soil, open ground, Big Spring, Howard Co., 9 July 1917, Palmer 12491 (СА, M, US); 11% 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 413 miles east of Seminole, Gaines Co., 20 May 1935, Parks 4: Cory 11707 (T); Brown- field, Reed (US TYPE, not seen); Brownfield, 8 April 1935, Reed (TTC); sandy soil, about 12 miles southwest of Lamesa, 22 April 1935, Reed (TTC); loose and sandy soil, 1 mile west of Shaektown, 14 J une 1934, Reed 3718 (TTC) ; sandy, semi- arid soils, level ground, Cedar Lake, about 20 miles southwest of Lamesa, 14 1934, Reed 3719 (TTC) ; loose and sandy soil, west of Ackerby, 15 June 1934, nie 3735 (TTC, US); sandy soil, railroad right-of-way, Meadow, 5 March 1934, Reed 3897 (ТТС); loose sandy soil, between O’Donnell and Lamesa, 16 Sept. 1934, Reed 4103 (TTC); Meadow, 4 July 1935, Reed 4200 (TTC); between Wellman and Meadow, 29 July 1934, Beed 4354 (TTC). 12a. E. Coryi var. viscida Cutler,?? n. var. Differs from the species in having the aerial stems frequently branching, the young stems viscid, and the bracts not fleshy. Distribution: southwestern Colorado, northwestern New Mexico, and adjacent Utah and Arizona. SPECIMENS EXAMINED: LORADO: Deer Run, Gunnison watershed, alt. 1430 m., coll. of 1901, Baker 921 (P); plains south of Maneos, 8 July 1898, Baker, Earle $ Tracy 397 (M, Р); San Juan Valley, July 1875, Brandegee 7754 (М); dry situations, Chureh Rock Canyon, 17 June 1927, Cottam 2319 (BYU) ; Gunnison Mesa, Grand Junetion, 15 May 1916, Eastwood 5121 (CA); Book Cliff road, Grand Junction, 18 May 1916, Eastwood 5190, 5191 (CA, В); clay, Grand Junction, alt. 1360 m., 21 June 1894, Jones 5476% (Ру; foothills and mountains, Mesa Co., summer of 1893, Long (G); Spruce Canyon, near eamp ground, Mesa Verde National Park, 8 July 1929, Mathias 645 (M, P); dry hills, alt. 1650 m., 28 May 1914, Payson 367 (М, 5) ; Glenwood Springs, 1 Sept. 1917, ыгын 1199 (9; talus slope of sand and shale, Colorado National Monu- ment, 10 m southwest of Fruita, i 1830 m., 13 Aug. 1937, Rollins 1931 (CA, М); dry, гы ілі Paradox, alt. 1610 m ко ИВА Co., 22 June 1912, Walker 161 (M); dry canyon slope, Norwood HR alt. 2200 m., e Miguel Co., 20 Aug. 1912, Walker 511 (M, P). New Mexico: Frijoles Canyon, alt. 2000 m., vicinity of Santa Fe, 4 June 1936, Arséne 22799 (US); са Cuba road, near Bloomfield, San Juan Со., 4 July 1929, Mathias 611, 612 (M, Р); dry n ads 1550—1650 m., vicinity of Farmington, San Juan Co., 17 July 1911, Standle 8 (US); оаа side, Bandelier National М 24 Tal 1935, PRA d 4 Langford 52449 (US). ARIZONA: desert near Tuba, 15—31 July 1920, Clute 100 (M) ; Montezuma Castle National Monument, Yavapai Со., 20 May 1937, Cutler 1115 (М, UW); sandy 2 15 miles east of Tuba City, Coeonino Co., 21 May 1937, Cutler 1147 (M, ); Monument Canyon, 7 miles southeast of Chinle, Apache Co., 12 June 1938, rt 2143—2148 (M); Canyon de Chelly, near Chinle, Apache Co., 13 June 1938, Cutler 2156 (M); loose sand, 4 miles south of Round Rock, Apache Co., 14 June » Е. Coryi var. viscida Cutler, var. nov., a specie differt caulibus ligneis aeriis saepe ramosis, juventate viseidis, braeteis non valde earnosis et non saepe esculentis. [Vor. 26 414 ANNALS OF THE MISSOURI BOTANICAL GARDEN 1938, Cutler 2161-2165, 2169, 2170 (М); sands of mesa, 5 miles west of Rock Point, Apache Co., 15 June 1938, Cutler 2174, 2188, 2200 (M); loose sand, 10 miles west of Rock Point, 15 fune 1938, Cutler 2209 (М түре), 2210 (М); loose sand, 5 miles south of Dennehotso, Apache Co., 15 June 1938, Cutler 2214, 2216, 2218, 2219 (М); between Tuba City and Tonalea, Coconino Co., 10 Sept. 1938, Eastwood § Howell (CA); between Kayenta and Monument Valle ый Navajo Co., 14 Sept. 1938, East- wood $ Howell (СА); near Canyon Diablo, Coconino Co., 18 May 1931, ^is 2284 (P); steep, rocky, brushy slopes near Indian Gardens, Oak Creek Canyon, 23 May 1935, Nelson d-Nelson 2087 (М); near Ganado, 17 May 1934, Polos 9352 (ОБ); sandstone bluff, edge of marsh, alt. 1520 m., near Tuba City, Navajo Со., 2 June 1935, Peebles $ Fulton 11857 (US); 14 miles north of Kayenta, alt. 1600 m., Navajo Co., 4 June 1935, Peebles $ Fulton 11935 (US); gorge of the Little Colo- rado River, alt. 1650 m., Coconino Co., 8 June 1937, Peebles & Smith 13340 (US) ; in sand, 5 miles southeast of Tuba City, alt. 1550 m., Coconino Co., 8 June 1937, Peebles $ Smith 13361 (US) ; Oraibi, alt. 2000 m. | Абу 1935, Whiting 756/732 (UNM); Navajo Springs, 24 July 1892, Wooton (N Uran: cliffs, Moab, 7 June 1927, зен ns (BYU); ; sandy bluff, alt. 1800 m., Blanding, San Juan Co., 1 July 1927, Cottam 2502, 2518 (BYU); dry flat, Monu- ment Valley, alt. 1680 m., 2 July 1927, Cottam 2566 (BYU) ; hills above Comb Wash, 8 miles west of Bluff, San Juan Co., 21 June 1936, Cutler 2328 (M); loose sand, 4 miles north of Bluff, San Juan Co., 21 June 1938, Cutler 2340, 2341 (М); 6 miles northwest of La Sal Junction, San Juan Co., 23 June 1938, Cutler 2365 (М); under an overhanging eliff of Augusta Natural Bridge, San Juan Co., 7 May 1933, Har- rison 5913 (M); canyon bottom, Augusta Natural Sg "e Juan Со., 7 May 1933, Harrison 5914 (M); Moab, 30 Aug. 1891, Jones (P); 1% miles east of Armstrong Canyon, National Bridges Monument, alt. 1750 m., San Juan Co., 22 June 1932, Maguire § Redd 1631 (M); western slope of La Sal Mts., near Little Springs, alt. 2000-2200 m., 5-6 July 1911, Rydberg 4 Garrett 8571 (US). This variety is dominant over extensive stretches of sandy desert in the Navajo Indian Reservation and near-by regions and forms large hummocks. Іп the north and at high altitudes it is difficult to distinguish vegetative material from E. viridis, but the long peduncle of the ovulate strobili and the usual viscid stems distinguish other specimens. A probable hybrid of this variety and E. Torreyana has been given the binomial Ephedra arenicola earlier in this paper. 13. Ephedra antisyphilitica Berland. ex C. A. Mey. in Mém. Acad. Imp. Sci. St. Petersburg, VI, Sci. Nat. 5: 291. 1846. E. occidentalis Torr. ex Parl. in DC., Prodr. 16?: 354. 1868. E. texana Reed in Bull. Torr. Bot. Club 62: 43. 1935. Егесі or spreading dioecious shrub, 0.25-1 m. high; branches stiff, hard, terete, up to 4 mm. thick, alternate or whorled at the nodes, angle of divergenee about 48 degrees; internodes 9-5 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 415 em. long; young stems green, glaucous, almost smooth, with many small longitudinal furrows, becoming yellow-green, then gray-green; bark of older stems cinereous, slightly cracked and fissured; terminal buds 2-3 mm. long, obtusely pointed; leaves binate, 1-3 mm. long, obtusely tipped from a dorso- median herbaceous thickening, connate for two-thirds to nine- tenths their total length ; sheath membranaceous, later splitting and falling ; staminate spikes solitary or paired at the nodes of the young branches, lanceolate-elliptie, 5-8 mm. long, almost sessile, 5-8 pairs of bracts, obovate, one-eighth connate at the base, 2-3.5 mm. long, 2-3 mm. broad, slightly thickened, mar- gins membranaceous, pale green to reddish, the lower pair empty; perianth slightly exceeding the subtending bract; staminal column 4—5 mm. long, one-half exserted, with 4—6 ses- sile or very short-stipitate anthers; ovulate spikes solitary or paired at the nodes of the young branches, rarely several at a node, elliptie, 6-11 mm. long, nearly sessile, 4—6 pairs of braets, ovate, one-eighth to seven-eighths connate, the inner pairs be- coming fleshy, red, succulent when ripe; seed solitary, trigonal or occasionally tetragonal, light brown to chestnut, smooth, 6-9 mm. long, 2-3.5 mm. broad, conspicuously exserted ; tubillus straight, slightly exserted, ligulate limb slightly contorted. Distribution: southwestern Oklahoma, and west-central Техав to northeastern Mexico. SPECIMENS EXAMINED: OKLAHOMA: along the Red River, Harman Co., 16 Dec. 1933, Goodman $ Barkley (TF, G, M). TEXAS: desert d тірі Nolan Co., 3 Aug. 1934, Barkley (М); Rio Frio, ‘‘entre Laredo et Пе) ' Feb. 1828, Berlandier 1590 [-320] (C, M, co-TYPES); ig Springs, 20— 28 May 1899, Bray 394 (US); San Antonio, Bexar Co., 15 April 1911, Лететз $ Clemens 880 (CA, M, P); 9 miles northwest of es : Hidalgo 80 Dec. 1933, Clover 1593 (CA); 3 miles east of San Angelo m Green Co., 2 April 1931, pae d 15 miles north of Eldorado, Sobleleher od 29 April a Cory E Б n Camp, Matador Ranch, Dickens Co., 15 June 1904, Coville 1871 US); Texas К ш Experiment Station жойы 14, b si of Rock vidil: RE. Co., 24 May 1938, Cutler 1815, 1816 (M); re 12 miles south o Sonora, Sutton Co., 24 May 1938, Cutler 1817 (M); aa field 10 miles south 5 ику Sutton Co., 24 May 1938, Cutler 1819, 1820 (M); 12 miles southwest of utton Co., 24 May 1938, Cutler 1822 (M); 14 miles south of Juno, Val Verde Со., 24 Мау 1938, Cutler 1830 (M); pastures, 7 miles west of Comstock, [Vor. 26 416 ANNALS OF THE MISSOURI BOTANICAL GARDEN Val Verde Co., 24 May 1938, Cutler 1831 (M) ; along railroad 4 miles w. of Shumla, Val Verde Co., 24 May 1938, Cutler 1833 (M); pasture № mile west of Dryden, Terrell Co., 24 өлш sgh Cutler 1887-1839 (M); gravel plain 1 mile west of San- derson, Terrell Co., 26 May 1938, Cutler 1840-1842 pe along railroad 8 miles west of Sa айн, d Со., 26 May 1938, Cutler 1845 (M); rocky hills near Stanton, Martin Co., 13 June 1900, Eggert (M); hills and valleys, Laredo, 18 Өзеу 1919, Hanson 344 (G, M, UW); Nibo Mt., Gillespie Co., Jermy 154 (M, US); Experiment Station, Sonora, 21 April 1931, Je 28371 (CÀ, M,E,.B) Раде. 24 March 1932, Jones 29009 (М); below Laredo, 26 March 1932, Jones (Р); between Uvalde and Del Rio, 18 April 1931, McKelvey 1895 (P); between the Frio and the Nueces rivers, on the road to Laredo, 27-28 Jan. 1880, Palmer 1289, 1292 (М); dry limestone hills, Сопсап, Uvalde Co., 14 June 1916, Palmer 10190 (US, В); dry limestone hills, San Angelo, Tom Green Co., 28 June 1916, Palmer 10309 (М, 8, ); dry caleareous hillsides, Telegraph, Kimble Co., 8 Oct. 1916, Palmer 10951 M, Т/Б); sandstone hills, Campbelton, Atascosa Co., 9 March 1917, Palmer 11238 (CA, M, UC, US); dry rocky hills, 5 Brown Co., 18 Oct. 1917, Palmer 13028 (CA, M, US); dry limestone ledges near песмом Brown Co., 31 Oct. 1924, Palmer 26783 (M); along саргоек sinn and the broken country to the eastward, Buffalo Springs, Lubbock, 15 April 1934, Reed 3628 (US); ealiehe soil along varie Buffalo Springs, Lubbock, Reed 3946 (R); Buffalo Springs, Lubbock, 30 Sept. 1934, Reed 4113 (В); Johnson's ranch, Yellow House Canyon, Lubbock, 2 March 1935, Reed 4143 (R); Rocky Bluffs, Brown Co., April 1882, Reverchon 925 (F, M, US); vicinity of Langtry, 27 March 1908, Rose 11621 (US); pasture, La Salle Co., 4 May 1919, Schulz 90 (US); near Paint Rock, Concho Co., 27 April 1931, Terry Vet 1 (P); near Eagle Pass, Maverick Co., 6 Aug. 1925, Tharp 3334 ind San Antonio, Wilkinson 113 (M). МЕХ! SAN LUIS POTOSI: region of San Luis Potosi, 1878, Parry 4 Palmer 854 (M). NUEVO LEON: mountains near Ieamole, 3 Feb. 1907, Safford 1251 (M). Ephedra antisyphilitica and E. pedunculata have been re- garded frequently as a single species, yet they are very distinet and no true intergrading forms have been found. Тһе former species rarely has a pair of seeds but never assumes the clam- bering habit or attains the long stipitation of the anthers that characterizes E. pedunculata. The latter appears frequently to have a habit of erect growth when it has been repeatedly grazed over by stock. xn = antisyphilitica var. brachycarpa Cory in Rhodora 40: 1938. n the species except the ovulate spikes are shorter, less than 6 mm. long, and broader ; seed broader, about 3 mm. wide, definitely trigonous, included. 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 417 Distribution: known only from Kent and Bexar counties, Texas. SPECIMENS EXAMINED: : eastern Bexar Co., 25 March 1935, Parks 12175 (US TYPE, not seen); eastern Bow Co., 25 March 1935, Parks, 12176, 12177 (Т). 14. Ephedra compacta Rose in Contrib. U. S. Nat. Herb. 12: 261. 1909 Erect or spreading, compact dioecious shrub, 0.3–0.5 m. high ; branches stiff, hard, almost terete, up to 2.5 mm. thick, opposite or whorled at the nodes, angle of divergence about 379; inter- nodes 0.5-3 em. long; young stems gray-green, glaucous, with several longitudinal furrows, becoming distinctly gray; bark of older stems gray-brown, lightly fissured and eracked ; termi- nal buds about 1.5 mm. long, conical; leaves opposite, 1.5- 3 mm. long, obtusely pointed, connate for one-half to seven- eighths their length ; sheath chartaceous, red-brown in earlier stages, later gray and divided, subpersistent ; staminate spikes not seen; ovulate spikes solitary or paired at the nodes of the young branches, ovate, 4-8 mm. long, almost sessile, 3—5 pairs braets, broadly ovate, 4-5 mm. long, 3-5 mm. broad, one-eighth to three-fourths connate when mature, the inner pairs red and succulent ; seeds paired, light brown to chestnut, almost smooth, 3.5—5.5 mm. long, 2-3 mm. broad, slightly exceeding the bracts ; tubillus straight, barely exserted, the tip truncate. Distribution: east-central Mexico, Coahuila to Oaxaca. SPECIMENS EXAMINED: MEXIC OAXACA: E as Naranjas, Aug. 1908, Purpus 3054 (F, M, US). PUEBLA: Esperanza, Sept. 1911, Purpus 5698 (F, M, US); near Tehuaean, 1-2 Aug. 1901, Rose $ Нау 5835 (US); near El Riego, Tehuacan, 2 Ma 1905, Rose $ Нау 10023 (US); hills west of town, near Tehuacan, 2 Sept. 1906, Rose $ Rose 11274 (US TYPE); near Tehuacan, 30 Aug.-8 Бері. 1905, Rose, Painter ф Rose 10023 (US). SAN LUIS POTOSI: Chareas, July-Aug. 1934, Lundell 5165 (CA, F, US). COAHUILA: rocky soil, battlefield near Buena Vista, 19 Мау 1848, Gregg 53 in part (G, 15. Ephedra pedunculata Engelm. ex Wats. in Proc. Am. Acad. 18: 157. 1883. [Vor. 26 418 ANNALS OF THE MISSOURI BOTANICAL GARDEN Vine-like shrub, trailing on ground or clambering over bushes and trees, often to a height of 6-7 m., dioecious; branches lax, firm, terete, up to 3 mm. thick, alternate, or rarely, whorled at the nodes, angle of divergence about 52 de- grees, internodes 1-7 cm. long; young stems gray-green, glau- cous, almost smooth, with several moderately deep longitudinal furrows, becoming more green, then yellow-green; bark of older stems cinereous, slightly cracked and fissured; terminal buds 1-3 mm. long, attenuated; leaves binate, 1-3 mm. long, obtusely tipped from a dorso-median herbaceous thickening, connate from two-thirds to nine-tenths their total length; sheath membranaceous, later splitting; staminate spikes soli- tary or paired at the nodes of the young branches, lanceolate- elliptic, 4-8 mm. long, peduncles 0-12 mm. long, 6-12 pairs of bracts, obovate, free or one-eighth connate at the base, 1.5-3.5 mm. long, 1.5-3 mm. broad, slightly thickened, margins mem- branaceous, pale yellow to reddish, the lower pair empty ; peri- anth slightly exceeding the subtending braet ; staminal column 3—5 mm. long, one-half exserted, with 4-6 definitely stipitate anthers; ovulate spikes solitary or paired at the nodes of the young branches, rarely several at a node, elliptic, 6-10 mm. long, peduncles 1-20 mm. long, 3-6 pairs of bracts, ovate, one- eighth to seven-eighths connate, the inner pairs becoming fleshy, red, succulent when ripe; seeds paired, trigonal, light- brown to chestnut, smooth, 4-9 mm. long, 2-3.5 mm. broad, con- spicuously exserted; tubillus slightly kinked, somewhat ex- serted, limb contorted. Distribution: southwestern Texas east of the Pecos River, to San Luis Potosi, Mexico. SPECIMENS EXAMINED: XAS: between Barrocetes ranch and Aquilares, Zapata Co., 19 Dec. 1933, Clover 1584 (CA); Ranch Experiment Station, Edwards Co., 9 Sept. 1931, Cory (M); climbing on fence and on spiny shrubs, 12 miles south-southwest of Sonora, Sutton Co., 24 May 1938, Cutler 1821 (M); climbing over trees and shrubs, 14 miles south of Juno, Val Verde Co., 24 May 1938, Cutler 1827 (M); 1890, Nealley 258 (F, R); Uvalde, 90 miles northwest of San Antonio, 1880, Palmer 1291 (M TYPE, US); Rio Frio, Oct. 1851, Parry (M); Barrens, Brown Co., April 1882, Reverchon (Е); Uvalde Co., June 1846, Reverchon 1658 (M). 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA 419 MEXICO: TAMAULIPAS: La Sardiña, Sierra de San Carlos, alt. 650 m., 14 Aug. 1930, Bart- lett 1095 (US). SAN LUIS POTOSI: 1879, Palmer (I); San (US); San pn Potosi, is Parry ғ P E Р, UB. LEON: Lampazos, + b Edwards (F). Potosi, Aug. 187 NUEVO 9, Schaffner COAHUILA: States of Coahuila and Nuevo 100 miles north of Monelova, Sept. КОЗ): ; Juarez Saltillo, 1898, Palmer 283 (F, M en route from San Luis Potosi to ud a Dee. 1878—Feb. Luis Potosi and Morgen July-Aug. Palmer , Palmer 702 (F, I, M, p San Luis Leon, July 1880, Palmer 1289 (I, M, 1880, Palmer 1290 (I, M, US); ZACATECAS: plains, Cedros, Duns 1908, Lloyd 75, 214 (M, US); near Concepcion del = 22 Nov. 1902, Palmer 372 (U S). April 1885, рінен 184 (F, US); Sta. S) in CH HUA: Bachimba Can 15 Eulalia | nuu 13 April 1885, Wilbineon 117 (U DURANGO: dry valley between Mapimi and Gusjuguille, m April 1867, Gregg 484 (M); Durango, April-Nov. 1896, Palmer 149 (F, M, US) List or ExsriccATAE The distribution numbers are in italics. Unnumbered collections are indicated by а dash. The numbers in parentheses are the species numbers used in this mono- graph. Abrams, и Коу. 3204, 3489, 3600, 3676 in part (6); 3676 in part (10); 11769, me (11). Abrams, L. R., & E. A. MeGregor. 499 (7); 174, 217 (11). Allen, Eva. 177 (1). Anthony, A. W. 281 (7). Aplin, J. A. — (11). Ый, Е. 1. 6904 (11). Arséne, Bro. С. 19034 (3); 22799 (12a) Atsalt, Ferris. 0). Baker, Carl F. 921 in part (6); 921 in art (12a) Baker, C. F., F. S. Earle, & S. M. Tracy. Barkley, Fred A. 3252 1 2115, 3333 a 1); — (13); see—G. J. Goodm arlow, Bronson. — (1). жы ы. Нису cii 1095 (15). Bartram, Edwin В. 16 (1). Becraft, E ^g „ see—B. Maguire. е” 8). Веп En 3358 (6); 3446 (10). Ponit J. L. [320] 1590 (13). Bigelow, J. M. 3 (1); 4 (3); 2 (7). od, H. L., see—B. Maguire. Bolton, A. L. — (11). Braem, Selma. — (6); — (9). Bray, William. a (13). Brandegee, T. 8. — (7); 7754 (12a). Brewer, Шы. H. 347 (11). hn I. А Chandler, Н. P. 5165 (6). Clausen, J. 797 (11). Clemens, Mr. & Mrs. Joseph. 380 (13). Clemens, Mrs. бије: um — (T). Cleveland, D А W. 7816 (3); 8225 (5); 6510-6514 "n 7465 (10); 6516, 7127, 7027, d (11). ey, I. W., & Bonnie C. Templeton. 5675, 5676 (б); 5784 (6). [Vor. 26 420 ANNALS OF THE MISSOURI BOTANICAL GARDEN Clover, Elzada U. 1593 (13) ; 1584 (15). Collom, Mrs. Rose E. 341 (1) Cooper, Juan, — (9). Coquillett, р. W. — (10). € pape L. 2829 (3); 920, 922, 924, , 18548, 18736 (7); 13711 (19); — n: — (15); see—H. B. Parks. Cottam, W. P. 2077, 2611, 6843 (3); 4083, 4701 (10); 1189, 2610, 3300, 368, 4115, 4380, 4630 (11); 2138, 2319, 2502, 2518, 2566 (12a). Coues, Elliott, & Edward Palmer. 570 3 (3). Coville, Frederick Vernon. 1871 (13). Coville, F. V., & F. Funston. 387, 923 (11). Coville, F. V., & M. F. Gilman. 19, 108 407—410, 444, 445, 447, 448, 502, 502a (5). Cox, M., see—R. A. Studhalter. Craig, T. 919 (5); 1450 (11). Curtin. — 108 (3). Cutler, Hugh Carson. 622, 1852-1859, 1987, 1988, 1990-1997, 2004-2015, 1846, 1851, 1863-1868, 1908-1905, 1926, 1958, 1963, 1964, 1966, 1969 (7); 2873-2375, 2433-2435 (11); 1115, 1147, 2143-2148, 2156, 2161- 2165, 2169, 2170, 2174, 2183, 2200, 2209, 2210, 2214, 2216, 2218, 2219, 2328, 2340, 2341, 2365 (аға); 1815- 1817, 1819, 1820, 1822, 1830, 1831, 1888, 1837-1839, 1840-1842, 1845 (13) ; 1821, 1827 (15). Demaree, Delsie. 7475 (12). Detwiler, S. B. 21 (1). Diehl, I. ЈЕ. — (3). Dudley, W. R. — (6). Dudley, W. R., & Е. Н. Lamb. 4609 (11 Ys Victor. 501 (11). Duthie, R., see—R. S. Ferris. arle, F. S. see—C. F. Baker; see— S. M. Tracy. Eastwood, Alice. 6348, 8115, 8192, ui 6004a, 6017, 6032, xe. 6057, 0 7 2, 14719, 14742, 14761 а 1); 4141, 5190, 5191 (12а). astwood, А., & J. T. Howell. 6704, — (3); 4273, 4274, 5129, 5130 (6); 29, 934 (11); (12a) Edwards, Mary T. — (15). Eggert, Henry. — (1); — (7); — (12) ; — (13). Eggleston, Willard W. 16269, 16508 (1); 19706 (6); 10148, 10191 (11). Elis, J. H., & Ledman. — (1) Elmer, A. D. E. 3539 (10) Engelmann, George. — (1); — (6). Engelmann, Henry. — (10). Epling, Carl Clawson. — (6); — (10). Epling, C. C., & W. Robison. — (6); Epling, C. C., 6 W. Stewart. — (6). Esau, Katherine Ferris, Roxana 8. 7128 98 (1); г 6953, $012, 9140 (6); 909, 1347, 7283, 7702 (10); 3741, 7857, 7955 (11). Ferris, В. S., & В. Bacigalupi. 8128 (6); 8502 (6). Ferris, R. S., & Б. өзен 4 (11). Ferris, R. 8, F. M. Scott, & R. Baciga- lupi. 4036 (5); 3874 dio: Fi L g 8381 (6); 83960 (7); 8500 (11). 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA Fulton, H. J., see—R. H. Peebles. Funston, F., see—F. V. Coville. Gaines, G. W. 1). Gallegos, J. M. 1355 (6). Galway, D. H. — (3). Gander, Frank F. 2955, 3028, 13454 (6); 138.12, 1275 (9). . Rydberg. Gillespie, D. к. 9847 (11); see—I. L. Wiggins Gillespie, J. W. 5529 (9). Gilman, M. F., see—F. V. Coville. Godwin, A. — (3). Goldman, E. A. 1127, 1196 (6); 2075, 2210 (11); see—E. W. Nelso Goodding, Leslie N. 2268 (1); 677а, 34a : Goodman, George Jones. 2220, 2234a (3). it on G. J., & F. A. Barkley. — eae R. — (8). Goulding, J. M. — Graham, Edward H. 6123, 6171, 8840, 8933 (3); 8813, 9073, 9147, 9521 (11). Grant, George B. — (3); 5644 (11). Greene, Edward L. — (1). Greenman, Т рлы More, Jr. Turner. ?4 (1). Gregg, 142 53 in part, 414 (7); 53 in part (14); s 2. riffiths, David. 3534 (1). Grinnell, е y (10a). А G. — (11 Hall, D.— (3) ; — (11). Hall, i M. 5979 (6); 6212 (10); 5 (11 Hanson, Herbert C. (13). & Milton A166 (3); 844 Harbison, C. F. 14851 (6). Harris, J. Arthur. M27134, C27713 11); үка; В, Е, ‚ 7398 (3); 6805, 806 (10); on 8328, 8329 u E vA 6914 (12a); see—W. D. ton, 421 Harrison, J. G., & T. H. Kearney. 7586 (9). Hart, Cecil. — (6); — (10); 81 — (11). Hartman, C. V. 642 (1). Harvey, Mrs. D. R. 535 (6); 588 (7). uus R. D., see—P. A. Munz. e—J. N. Rose. 3 (11). Heller, A. Афи. 7743 (6); 7703 (10); 8299, 10411 (11). Heller, A. A., & E. Gertrude. 3623 (3). Henderson, L. F. 8670 (10) Hermann, F. J. 4920 (11). Hinckley, L. C. 257 (1). Hitchcock, Albert S. 513 1/2 (11). Hitchcock, C. Leo. 12329 (5); see— P. A. Munz. Hough, W., see—J. W. Rose. ough, Mrs. W. — - Howell, John Thomas. 3643 (5); 3247, 3409 (6); 2498, 2529 (10); 3824, 3924, 5028 (11); see—A. Eastwood. Jaeger, E. C. 1061 (11). Jepson, рту L. 4784 (6); 4831 (10). Jermy, C. А Johnston, B M. 3020 (6); 8257 (7); 5029af, 5029ag, 5077az, Du 5468, 25962, 25964m 3 (5); 3 ja 3726, 25963, 28372, — (8); 5062, 29008, — (2); а); 28371, 29009, Jones, W. W. 434 (1). Kammerer, ird L. 5 (3). Kearney, T. АЛ To Harrison. Kearney, T. H H. бе, 7748, 7759, 10897 24 T1 (11). 422 Keek, David D. 1833, 2248 (6); see— P.A Kellogg, N. B. — (3). Kendall, L. — (11). Kennedy, P. B. — (3); 1841 (9); 999, 10 , C. — (11). Kirkwood, J. E. 24 (7). Kirkwood, J. E., & F. E. Lloyd. 86 (7). "eni E. — (1). mb, F. H., see—W. R. Dudley. pou M., "m A. Studhalter. Layton, D. V Ledman, O. 8, : BSA H. Ellis. Lemmon, J. G. 252, 287, — (7); 251, — (1 Ferdinand. 414 Lindheimer, in part men F. E. — (1); 75, 214 (15); see би. Lundell, C. L. 5165 (14). MacDougall, "Ae T. 100 (11). MacFadden, F. A. 14476 (1); 14425 MeGregor, E. A. 138 (6); see—L. R. Abrams. MeKelvey, Susan Delano. 1997, 1998 (1); 2287, 2288 (3); 2253 (7); 2285 (11); 2284 (12a); 1895 (13) MeMinn, H. E. 7431 (6) Maguire, Bassett, & В. J. Becraft. 2479 (10). Maguire, B., & H. L. Blood. 1277 (11). Maguire, B., R. & G. B. 4715, 4722 (3); 4723, 4717, 4719 AR Maguire, B., & . Redd. 1631 (12a). Мамеа Sister 5 1840 (3). arsh, Ernest G. 143, 694 (1); 64, 103 (7). — Н. L. 2058, 2059 (6); 1976, 977, 2021, 2021a (1). idus Mildred E. 613, 614 (3); 611, 612, 645 (12a). Mearns, Edgar A. 417, 2826, 2937 (1); [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN 3024, $332, 3864, 3923 (6); 2956 7 Mearns, E. A., & L. Schoenfeldt. 2916 Monnet, P. 1110 (1); $39 (11). Moore, John Adam, & Julian A. Steyer- mark. 3083, 3287 (1); 3258 (7). Mueller, C. H. 7951 (7); see—F. L. Wynd. Mulford, A. Isabel. 137, 187a, 1025 (1); 272 (7). Munz, Philip A. 1408, 7823 (1); 4548, $026, 9567, 9570, 13805 (6); 14983 (8); 12955 (9); 12468 (10); 6876, 6979, 8188, 11082 (11). Munz, P. A., & С. L. Hitchcock. 12072, 12073 (6); 12047 (9 Munz, P. A I. M. Johnston. 5286 (6). Munz, P. A., I. M. Johnston & В, D. етой. 1029 ran ‚ & D. D. Keck. 4789 (9); Nealley, T. C. 258 (15). Nelson, Aven. 10286 (8); 11280a (9); 9990 (11). Nelson, A. & R. 1259, 1290, 1619 (1); 2136 (3); 1716 (8); 2087 (12a). Nelson, E. W. 6014 (1); 4472 (7). Nelson, W. W., & E. A. Goldman. 7548 (6). Noldke, A. M. — (11). ). ii C. R. 1871, -- (6). ps p^" 1292 (13); 149, 283, 372, 702, 289 in part, 1290, 1291, 1292 — pond see—E. Coues; see—C. С Parry 1939] CUTLER—MONOGRAPH OF GENUS EPHEDRA Palmer, Ernest J. 30989 (1); 138873, 14155 42 cd 34145 (7T); 12491 1 0309, 10951, 11238, 13028, une (13). Parish, S. B. $222 (1) ; 9070 (9) ; 2974, 11841 (10); 207 (11). Parish, S. B. е W. F. 745, 753 (1); 653, 1153 (6); — (7); 1238 (8); 1368, 1369 (10). Parish, W. F. — (1). Parks, Н. B. 12175, 12176, 12127 (13a). Parks, H. B., ory. 11707 (12). Parry, C. C. — D; 250, — (3); — (6); 249, 251 in part (9); 251 in part (11); — (15). Parry, d C. & E. Palmer 854 (13); 855 Payson, a B. 108, 319, 353 (3); 367, 1199 (12a). Payson, E. & Lois B. 3833 (3). Gy Pearson, G. A. 22 Peebles, 53 H. 9352 (12a); see—T. H. Kearney Peebles, R. . J. Fulton. 11874, UE 11940 s ram. 11935 (12a). Peebles, R. H . Smith. 13340, 13361 (12a). Peirson, F. W. 7193 (1). Peirson, F. W., & I. M. Johnston. 6510 am) Phares, J. F. — (11). Poni, Charles F. — (7). Pringle, Cyrus Guernsey, 88, 868, 1589, — (1); — (6); 38, 39, — (7); (10); 134 (15). Purer, Edith A. 7127 (6). Purpus, А. 6, 269, 1102, 5334 (7); 5032 (10); 5312, 7087 (11); 3054, (14). id ipa M. seis 6320 (6). A. . L. Viereck. — (1). Бок, J. 925 I 1658, — (15). Reynolds, au — (1). Robison, бесін Lis C. Epling. Rose, J. 423 Rodda, Mrs. A. F. — (11). Rollins, Reed C. 1719, 1975 (8); 1981 (12a). Rose, Joseph Nelson, 16236 ЧЕ 11621 (13). R. Hay. 5835, 10023 (14). Rose, J. гі & W. Hough. 4928 (1). Rose, J. N., J. H. Painter & J. S. Rose. 10023 (14 Rose, J. N., & J. S. 11274 (14). Rose, L. В. — (11 Rothrock, EE Trimble. 80 (3). Rusby, Henry H. — (1) Russell, P. 6. 12207 (13). R g, Per Axel, & A. O. Garrett. 11634, 16140, 8 m E. 1251 (13). Schaffner, mang G. 279 (15). Sehoenfeldt, L. 3805 (6); see—E. A. Mea В, беды, Ellen D. 90 (13). Scott, F. М., quito S. Ferris. Sherff, Earl E. — rr Forrest. s. 6282 (1); 6842 E31 G., see—R. H. Peebles. жам С. №. 491 (11). Speneer, Mary F. 807? (6); 206 (9). Sperry, pen 558, 559 (7 Standley, Paul C. 38, 441 а; 6938 (12 Third We №. ? (3). Steyermark, bud AE вее—Ј. А. Moo ore. Stokes, S. G. — (6); — (10). Studhalter, R. A., M. Cox, & M. Lang- ford. 82449 (1 Фа). Templeton, Bonnie C., вее—1. W. Clokey. Terry, R. W. V21 (13). Tharp, B. С. 2224 (13). Thurber, George. T (Туз 3 3). Tidestrom, Ivar. 9300 (3); Dos: 10099 ; 2170, 9357, b 10200 (11). Toumey, J. W. — Tracy, 8. М., n d F. Baker. Tracy, S. M., & F. S. Earle. 66 (1). Train, e — (11). 424 Trelease, William. — (10). Upton, G. M., see—M. C. Wiegand. Van Dyke, Mrs. E. C. — (6). Vasey, George R. — (7). Viereck, H. L., see—J. А. б. Rehn. Walker, Ernest P. 161, 511 (12a). Watson, Sereno, 1108 in part (10); homas W. — (9). Whitehouse, Eula. 8339 (1); 8340 (7). Whiting, А. Е. 756 (3); 756/732 (12a). & G. M. Upton. 2979 Wiggins, I. L. 6508 (1); 4340, 4379 (6); 6755 (11). Wiggins, I. L., & D. K. Gillespie. 4016, 4062, 4085 (6). [Vor. 26, 1939] ANNALS OF THE MISSOURI BOTANICAL GARDEN Wilkens, Н. 1653 (7). Wilkinson, E. 117 in part, 120 (1); 118 (7); 113 (13) ; 11? in part (15). illiams, a O. 463 (11). Winblad, s W. — (6). "BAL "Frederick. 68 C15. Wolf, Carl B. 1870, 1871, 2555 (1); 2 — RLS с “~ с ~ ә Я © № S teo ne © E ка da 568, — min (122). Wright, Charles. 7584 (1); 1882 in part, 1883 in part (3); 273, 1883 in part (7 Wright, W. б. 188 (6). bin F. Lyle, & С. H. Mueller. 143 Nis Mary 8. 53 (7). uck, M. — (11). INDEX ro SCIENTIFIC NAMES Accepted names are in Roman type; synonyms, in italics; the principal reference and new names in bold face type. Page ОО 512255455 хы 382 ШИЛТЕ 525554509 33 A Sos 382 АОИ. 2.4: нь ка са а ь 384 antisyphilitiea 374, 376, 378, 414, 416 tisyphilitica Torr. ........... 384 antisyphilitica Watson ......... 8 antisyphilitica f. monstrosa .... antisyphilitiea var. brachycarpa . 375, 378, 416 antisyphilitica var. pedunculata . 404 arenicola сој секао ка , 414 aspera ...374, 376, 378, 379, 398, 407 јачим DA VEEPCER ES 376, 378, 395 Olokeyl ...... 378, 379, 380, 402, 407 compacta ......... 375, 376, 378, 417 КӨРУ aiiis data exi 78, 412 б! var. viscida .376, 378, 893, 412 distaehya ................ 374, 883 Завета ........... 375, 378, 401 cric WEINE MEAT ENDE 375, 378, 394 veris "TM 378, 388, 389 IJIOnoséehyR |... 2323 9.22 es 374 Page nevadensis ........ 5, 378, 404, 411 pias subvar. зік aha, он TERT VM 375, 405 nevadensis subvar. pluribracteata Teen ЖЕ Йез ey ee 375, 408 nevadensis f. rosea ........ 398, 407 ensis var. viridis ......... 408 occidentalis Torr. .......... 374, 384 occidentalis Torr. ex Parl. ...... 414 padunoulata пан crar hers Aag vis 374, 375, 376, 378, 416, 417 peninsularie ............... 375, 899 BON ауаз rai et, Te 375, 399 CONAN ТТГ ТҮК КЕ 375, 414 ТОГТОТАДА 5525, а а а 4, 376, 378, 879, 380, 388, ion 393, 414 мык а ЖҮ ТҮЛҮГҮ ГТ 384 US TU NL суы Uk a REC CORE я ...374, 376, 378, 379, 384, 389, 392 үшөп та ООРУРУН 389 БАТЫРЫ и но 384 viridis .....2..Г..2... 375, 378, 408 [Vor. 26, 1939] 426 ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 27 * Typical seeds with tubilli; typical staminate bracts with included perianths and antherophores. ANN. Mo. Bor. GARD., VoL. 26, 1939 PLATE 27 Е етті Lareniooks Etnfurce E.Torreyane Efunersa E,californice. Espera L.fasciculafa ECokeyi — E.nevadensis E.viridis ЕСогуі ҚҚ. У Eantisyohilitios Паля Ecompacts. Epedunculata Etrifurca ETorreyana Earenicolk Efunerea Ecalifornic 50465841 Laspera Lfascicul Селге Enevèdensis Eviridis EY Eantisyphilitica £ pedunculo, var. visca O Q5 Ion EPOR Lec ТАРАНЫ CUTLER—MONOGRAPH OF EPHEDRA [Vor. 26, 1939] ANNALS OF THE MISSOURI BOTANICAL GARDEN EXPLANATION OF PLATE PLATE 28 Geographical distribution of species of Ephedra. funer _ —————— чен leges: pps E. iini vie ыы > мды d TET Е. Clokeyi — — — — — = E.C —х—х— Е. Coryi var. viseida —||—||—||— - Fig. 4. E.antisyphilitieg —————— — E. compacta —||—||—||— pedunculata — — — — — * Norg: Since the maps were made E. funerea has been collected in southeastern Nevada (Clark Co.), and Е. nevadensis, in Harney Co., Oregon. ANN. Mo. Вот. GARD., Vor. 26, 1939 V a \ 9 \ \ X ~ - SE | Jw ! eei J X / PLATE 28 CUTLER—MONOGRAPH OF EPHEDRA GENERAL INDEX TO VOLUME XXVI New scientific names of plants and the final members of new combinations are printed in bold face type; sy nonyms and page numbers having reference to figures and plates, in ifalics; and previously published names and all other matter, in ordinary type. A Adenocalymma cocleensis, 307 Alehemilla aphanoides var. subalpestris, te itm 287 K., Panamanian Halenia deter- Allen, P. H., R. E. Woodson, Jr Almirante, collections i in, ЕА 1938, 269 Anderson, Rags ла and Ruth Peck Own- bey. e genetic Mio gra of spe- cific dieit ,9 e: New Or е 21% worthy, of tropical America VI, I 5 Panamanian, 299 : used in quud sd der = РЯ ^ ee-temper Arrabidaea iaaa 307; legi 307 7 S anam n, 301 elpiads, Two new, om the western United States, 261 "pis albicans, 264; brachystephana, californica, 208; Cryptoceros, Cutleri, 263, ; Davisii, 261, ; perennis, 264; acl 264 Aspidosperma 58 Auxin response in Nicotiana alata and N. La ngedorfüi 332, 349 B Bec, pnm Blake, 8. F., a pla ants p mined, by: Зета 314; Polygalaceae, 262; Blakea Woodsoni, 296 Bromeliaceae e, ТРЕТ іап, 275 Brown's ву medium, pora of Gibberella Saabinetii on, 104, 152 Buxaceae, Panamanian, 291 Buxus citrifolia, 291 C Calathea insignis, 279; lutea, 279; quad- rispicata, 278; sclerobractea, 279 Ann. Mo. Bor. GARD., Vor. 26, 1939 Camp, W. H., ng aiii Vacciniaceae determined by, 29 Е 310; Hum- nal Zone region, during 1938, 265 н inis ru 314 Carex Lema a, 274 Casita Alta, Ls 44 E 269 Celastraceae, Panam n, 291 Cells: 2t Notas alata an d N. Lan ngs- дог, 329, 330, 357, 360; variation of, in rela tion to strength. properties of w ood, 11 жеры: мај made in, Cellulose i in wood, 18, 25 Centronia phlom moides, 295 Chaetocladus Chiriqui: collections in, ko am ing summer of 1938, 265; meadow near summit of Voleán de Chiriqui, 26 рады а 294 Т” ‚Е. т. ап омы Ophioglos- aceae determined by, Columnea essc d 7:18 panamensis, 312; tomentulosa, 312 Comarostaphylis arbutoides, 297; chiri- quensis, 2 Compos Ке Panamanian, 31 Compression n li wood, 38, 44 ** Com sion Conidial и variation of, in Gibber- ella и 106, 1 Coniferous wood, b di study of, in адан; ion to its con nm 1 b Ilis Ko towar ma. I, Collections during he. I1 of 1988, chiefly by P. H. Allen n, and в 3. Seibert, 265 Coon's synthetie medium, variation of Gibberella Saubinetii on, 104, 152 Costus ig ак 8, 277; hirsutus, 278; Lim 267, 277, var. Wedelianus, 277; на. 7 Cotto nwood tree, temperatures in, 167 enii, E E р-, T trichostyla, 306; Woodsonii, 305, 3 (499) 430 Cuseutaceae, Panamanian, — Hugh Carson. MM of the rth ет вресіев of the genus Ephedra Cyperaceae, с АМРЕ bg Cyperus albomarginatus, 2 бурр edium caudatum, 279, Hartwegii, 280 Cytologieal study: of Gibberella Saubi- netii, 105, 140; of Nicotiana, 325, 349 ** Degree-hours'? in tree temperatures, 170, 171, 186 Density of wood in relation to strength, 2. Panamanian, 290 т. P arranged for finishing test s of wood tension specimens, 80 «c Druckhole,? ^2 E Elaphoglossum Dombeyanum, 274 Ephedra, — ph of = North Amer- s, 373 ican species of - gen Ephedra, 382; tisyphiliti ea, 414, br EPA rpa, 416; antis isyphiliti ica, an, 4 monstrosa, “390, var. pedun lata, 404 arenicola, 393; od 308; ок Жай үсің 395; Clok compacta, 417; Cor oryi, 412, keyi, 402; . vi cida, 413; distachya, 383; fascicu- lata, 401; funerea, 394; x intermixta, 388; monostachya, 374; nevadensis, 404, f. rosea, 407; nevadensis subvar. paucibracteata, 405, subvar. pluribrac- teata, 408 r. viridis, 40 ciden talis, 384, peduncw , 417 peninsularis, 399; Reedii, 399; texana, 414; Torreya 38 t , trifur rea, 384; ; trifurea, 389; trifurcus, 384; viridis, Epiden ndrum Bn 282; Boothii, а Ең) нагна 288; isomerum, { Lindenianum, 983; paleacewm, 283. prismatocarpum, 33 Euphorbiaceae, Panamanian, 289 F яғ. Ты 96; speciosis- — 300 E structure of, 6 Fibrillar a angle of wood i E ripas to strength, 21, 50, 84, 86, 88, 90, 92, 94 Forsteronia spicata, 269, 299 Fungi, variation in, 99 [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN Fusarium: saltation of, 142; g n m, 99, mycelial 'and мор stages of, 1 133 G Galeandra, 284; Batemanii, 284; Baueri, 28 Garland, Hereford. A microscopic study fec oniferous е Гг relation to its strength proper Genetic hel ric оғ С di ifference, аа . Langsdorffii, 328 Gentianaeeae, Panamanian, 298 Gesneriaceae, Pan ian, Gibberella Saubinetii (Mont Sace. ( Fusariu ptis nearum Schwabe), Studies on variation in, 99 Gibberella Saubinetii, ‚99; aerial myeelial tage 13 vidi = b^. rown on various me Studies on variation in 158; һурһа perithecium of, ; pio onnotal stage of, 138, 156; variation in strains, 110 Gleason, - namanian Ме. maceae pees Ас by, Goddard, Mary. Vi еден be rare (Mont.) Saee. ( Fusariu arum ма 99 Gonolobus ‘dubius, "3 3; lis, 305; onnicheanus, 303, 304 Govenia ciliilabia, 28 Greenman, ‚ Panama Senecio deter- mined by, 4” Growth: effect of hormone оп, o of Nie tiana, 332, 349; in relation to strength of wood, 6 elo brachycarpa, 296 Guttiferae, Panamanian, 294 Ы "7р аде ги 280; pauciflora, etifer нады и алта 9 -— thyacophila, 299; Woodson- Heliconia E 277; nutans, 276 Hemicelluloses in woo 8 chiriquensis, 288; obo- ata, 288 ко, 7^ of, on growth of Nico- tiana, 332, Hymenophyll a m Panamanian, 273 Hyperieum Woodsonii, 294 I — ма, ene pico res cotian and angsdo тіні ая | indicated үө their mibinsé to, 349 1939] INDEX Isoetaceae, Panamanian, 272 Isoetes cubana, 273; Gardneriana, 273; Malin nverniana, 273; Тт 979; Storkii, 273; triangula, 2 J Jonker, F. P., Panamanian Gentianaeeae paar by, 298 Juncaceae, Panamanian, 275 K Kohleria elegans, 309; serrulata, 309 Laestadia lechleri, 316; muscicola, 316 mperatur e onti, kgs namensis, 314, 324; purpurascens, 3 Lanol vilae Л effect of, on growth of наа Lecythidaceae, ОИНА апіа Leonian's agar, growth of *Gibberella Saubinetii on, 104, 107, 152, 158 Lignin x Mie 25 Liparis el Lisian eps «оде, 298 Luehea eandida, 2 undell, C. pont plants de- termined by: Buxaceae, 291; Cela- 92; aa 292 гаша согу mbifera, Luzula gigantea vis. vulcanica, 275 Lycopodiaceae, Panamanian, 272 Lycopodium erythraeum, 272 T Maeroscepis panamensis, 301, 302; tristis, 302 Maerosiphonia Braehysiphon, 98, var. ma ca, 97 Malaxis mao de Par- 11, 281% onii, 281, , 97; dissim- ilis, 96; equato orialis, “96; Jamesonii, 96; Lob эы 9: Maranta се Panam 278 ок Mando 309; macrophylla, Мер Maxillaria Boothii, 282; pubilabia, 285; ringens, 285; Rousseauae, 285 Maxon, Willi , Panama plants determine Hymenophyllaceae, by: 273; "Weg Г 272; Lycopodiaceae, 972; Polypodiaceae, 273 Ma паа М oni, 291, 322; verti- cillata, 431 Media, effect of various, on variation in Gibberella Saubinetii, 104, 150- 58 кык Panamanian Mese s bicorniculata, deo eres var. пак. 259 Mie Тазда. 2 Microscopic study of coniferous ood relation to its strength ӘУЕ Mixochimaera, Moisture co iin of wood, 28 Monnina хы d pue de ge of the orth American species of the genus "Ephedra , 878 ее тоа differences: betwee n Nie- otiana alata and N. Langsdorffii, 328 indieated by their response to in- doleacetie acid, 34 in biological groups, 325 A: C. V. Panama plants deter- ned Hi Gesneriaceae, 308; Isoeta- H Baci 257; Pittieri, 257 Musaceae, Panamanian, 276 p anian, 292 Myrtaceae, Pocta 295 N Nagel, Lillian. Morphogenetie differ- d N. New or otherwise noteworthy Apocy naceae oe tropical America. VI, 95, VII, 257 Nicotiana аят s, 328; alata, 328, 349, 351; Шекіш. 328; Langsdorffii, 328, st. "351; rustica, 328; Sanderae, Nicotiana alata and angle of dive 332, 333; cells of, e. 330, 357, 360; eorolla parts, 329, growt 59; genetic coefficients ferentiate, Pte inflorescences of, 336, 2 8, у №. Langsdorffi: respons id 349, сік 362, 370, 372; pollen grains of, 331, 335 Nds "hoi n „bicolor, #387; Cordesii, zs 320 287; ramonensis Е С Ферре р А 287 о Odontoglossum Oerstedii, 285 Ophioglossaceae, Panamanian, 274 432 Ophioglossum nudieaule var. tenerum, Orchidaceae, Panamanian, 279 Osmoglossum anceps, 285 Ownbey, Ruth Peck, Edgar Anderson and. The genetic coefficients of s spe- cifie difference, 325 P anama: camp at Casita Alta, № 269 ; Contributions toward а а flora of, eadow near summit of Voleán a 8 Chiriquí Paphiopedilum caudatum, 879 wm caudatum, 279 acrophylla, 294; у 294; "белесін, 292 "Uy, M., ye nama Alchemillas de- irn by, 2 Phragmipedium іе 279; Hart- melano- wegii, 280 Phragmopedilum, 280; Hartwegii, 280 P pig comen € determination of, cotia 344 Pon. loblolly А shortleaf, 34; effee of growth ring width = strength, 4; strength tests, 36, 4 I echinata, 34; atta, 34 r affectans , 269; Gigas, 269 roam trinervia var. luxurians, 317 Planks used for testing strength of wood, 82 Plastid development in Nicotiana, 333 Pleurothallis, Bourgeaui, 281; ma andib ia 281; polystachya, 981; vittata, 280 Plukenetia volubilis, 289 Polypodiacezae, "ee Ephippi um, 380; racemosa, Populus deltoides, study of temperature Poe dextrose agar, growth of Gib- berella Saubinetii p 104; at various temperatures, 110, Prestonia concolor 258; isthmica, 300; remedio orum, 267, R Rauwolfia canescens var. glabra, 299; hirsuta var. pedi 299 Renealmia "wm 278 est S. В temperatures 165 150—156 259; den tigers, obovata, 259; Richards’ agar, variation in Gibberella Saubinetii on, 105, 152 [Vor. 26 ANNALS OF THE MISSOURI BOTANICAL GARDEN mes Mira. iion, 285 Rosa PUN nian, 287 ““Rothol Rubia amanian, 3 elite cornifolia, 818; жөні, 313; isthmens Mieten M M 275 8 Sabazia pinetorum, 317, var. dispar, 317; triangularis var. papposa, 317 Saldanhaea Seemanniana, 30 Saltation in fungi, 100 Saurauia Seibertii, 290 Schultesia brachyptera f. heterophylla, 298 = Russell J., Robert E. Woodson, Jr. . Co ntributions toward a flora а. ПІ, Collections during the summer of 1938, chiefly by R. E. em Jr, P.H. Allen, and Ri Seibert, 265 айырады caudatum, wegii e£ Suns 314 Smit . B., Panamanian Bromeliaceae ied by, Yr: cosi australis, 311; 279; Hart- calycosa, Specific difference: The genetic coeffi- cients of, 325; "a formula for measurement of, 3 Speeifie gravity of t in relation to Standley, P. C., determinations ап- lants b len Din 290; E — 280; Guttiferae, 294; Myrtaeeae, 295; Ru ubiaceae, Порри obo vata v var. mollis, 299 Strength pee yd coniferous wood, 1; fibrillar angle о f, on in relation to, 10; review o — gees spring wood and summer- n rel , 9, 39 Struthiopteris loxensis, 274 Studies on vari in ibbe vs Saubinetii (Mont.) Басе. (2 Jus be), 9 anamanian Cypera- ceae determined by, 274 T Tabebuia chrysantha, 308; heterotricha, va etree” 4 Те effeet of, а” rella Baubinetil, "107, 110, 1939] INDEX ps rire of trees, 165; apparatus sed in study o of, aun 166; charts gre ag, atmosphere on, 171, of soil, 223, of ао. 225 Бла а sts: axial, of ood, 42; in Bud мы рти Tiliaceae, amanian, 290 Tillandsia Pp ask lata, 275 Tracheid coniferous wood, 12; radial group 0 springwood, 86 ; radial 2 1 Transpiration, effect of, on tree temper- Tree сее and thermostasy, 165; I vr id 170; eharts ghow- ing Trees, E d mieroseopie study of wood of, in relation to strength prop- ertie Trichomanes MEE 278 Tropical Amer New or otherwise notewor LE pene is of, VI, 95; VII Ei Friedrichsthaliana, 267, 309; Woodsoni, 267, 308 U United States, western, Two new As- clepiads from the, 261 DO E Panamanian, 297 Vallesia, 258 тыны in relation to tree temper- ature, 226 433 Variation: studies on, in fungi, 99; in Gibberella Saubinetii (Mont.) Sace., g Pai ct of different media , 110, йй aod Hp "ia 314 Vitaeeae, Pan 94 Vriesia Woodsont&na, 275, 318 Warrea ја ct 284 * *Weissholz,"? 3 Williams, Panamanian Orchi- daceae determined E — = ogy of, 11; planks used for testing, 82 ; tension fractures of, 61; traeheids in, 6, Wood planks aedi E" testing strength, cross-section fro Woodson, Robert E. Jr. New or other- f Panama. III, Collections „ҺИ the summer of 1938, chiefly by R. E. Woodson, Р, Н. Allen, са E. J. Seibert, 265 hisar ÍT Q., pr xa Cuscuta- eae ыа by, 305 Zingiberaceae, 271 í Zugholz,?' 3 2 Volume XXVI | e Number + Annals of the Missouri Botanical Garden FEBRUARY, 1939 A ride i кашу of eames Wood in oe to Its Strength р АОИ ымы н 2.....Негеіога Garland 1-94 PUBLISHED QUARTERLY AT FULTON, MISSOUR BY THE BOARD OF TRUSTEES OF THE MISSOURI азады, 2 GARDEN, ST. LOUIS, MISSOURI. ~ Entered as "e matter at the post-office at Fulton, Missouri, r the Act of March 3, 1879. Annals of the Missouri Botanical Garden А Quarterly Journal MEM Scientific Geamia from the Missouri Botanical Garden and the Graduate Laboratory of _ the Henry Shaw School of Botany of b bero e University in affiliation with the Missouri Botanical Garden Information The ANNALS OF THE MISSOURI BOTANICAL GARDEN appears four times dur- ing the ealendar year: February, April September, and November, Four numbers constitute a volume. Subscription Priee........ yp per volume Single Numbers ......... 0 eaeh * Contents of dae issues of the ANNALS OF THE MISSOURI BOTANICAL GARDEN are listed in the E Index, published by the H. W. Wilson Company. * Except No. 8 of Vol. 22, price $5.00, and No. 2 of Vol. 25, price $2.50. : Е STAFF OF THE MISSOURI BOTANICAL GARDEN Director GEORGE T. MOORE HERMANN VON SCHRENK, CARROLL W. DODGE, Pathologist Mycologist JESSE M. GREENMA EDGAR ANDERSON, Curator of the icd : Geneticist Ernest 8. REYNOLDS, Бовезт E. WOODSON, JER, Physiologist жий Cad Сок, о? е | NELU С. HORNER, | Librarian and Editor of Publications BOARD OF TRUSTEES OF THE MISSOURI BOTANICAL GARDEN GEORGE C. HITCHCOCK Vice-President DANIEL K. CATLIN Second Vice-President THOMAS S. MarriTT DUDLEY FRENCH А. WESSEL SHAPLEIGH ETHAN А.Н. SHEPLEY EX-OFFI CIO MEMBERS Gtorer В. Тнкоор BERNARD Е. DICKMANN, Chancellor of Washington Mayor of the City of University St. Louis WILLIAM SCARLETT, J. B. MACELWANE, 8.7. Bishop of the Sitesi of . President of the Academy of Missouri Scienca of St. Louis JOHN J. SHEAHAN President of the Board of Education of St. Louis GERALD ULRICI, Secretary