bluuebunny/crossref_metadata_2025 huggingface dataset:
PARAPHYLLANTHOXYLON ALABAMENSE—A NEW SPECIES OF FOSSIL DICOTYLEDONOUS WOOD
Authors: Cahoon Elizabeth J.
Published: January 2018

A new species of fossil wood,Paraphyllanthoxylon alabamense, is described from silicified logs collected in Macon and Elmore counties from the Tuscaloosa Group, Cretaceous, Cenomanian‐Turonian Stage. All of the logs examined from this area have the same general characteristics and are placed in the new species.Paraphyllanthoxylon alabamenseshows many characteristics intermediate between the two previously described species but it is not identical with either of them. This wood is probably not identical with any living type but it resembles certain members of the Anacardiaceae, Buseraceae, Euphorbiaceae, and Sapindaceae. The large size and abundance of logs ofParaphyllanthoxylon alabamensesuggest that it was a dominant Cretaceous forest tree.
ATTEMPTS TO OBTAIN BACTERIA‐FREE PLANTS OF PSYCHOTRIA PUNCTATA (RUBIACEAE): GROWTH AND ROOT FORMATION IN CALLUS CULTURES
Authors: LaMotte Clifford E. , Lersten Nels R.
Published: January 2018

Attempts were made to obtain bacteria‐free plants of Psychotria punctata from tissue cultures. Stem explants and callus derived from them were induced to form roots but failed to form buds on Linsmaier and Skoog medium and 96 chemical modifications of it, including most of those known to induce bud formation in other species. Roots formed with ample IAA (2 mg/liter or more) and a low kinetin concentration (0.25 or 0.50 mg/liter). Adenine inhibited root formation in these media, but tyrosine did not. Tyrosine did lower the percentage of calluses commencing growth. When enzyme‐hydrolyzed lactalbumin (1.3 g/liter), kinetin (0.5 mg/liter) and IAA (5 mg/liter) were added to Linsmaier and Skoog medium modified by decreasing inorganic nitrogen and increasing inorganic phosphate, callus grew at the fastest rate observed (increasing threefold in fresh weight in three weeks) and formed numerous roots. This was adopted as the stock callus medium. Casein hydrolysates also stimulated growth but less so than lactalbumin hydrolysate. When lactalbumin hydrolysate or a casein hydrolysate lacking tryptophan was supplied, growth occurred without added auxin if sufficient cytokinin was added. Cytokinin was required at unusually high concentration and was tolerated at still higher concentration. Formation, elongation, and branching of roots persisted on a saturated solution of BA which inhibited callus growth about 70 % and delayed callus senescence. Light caused earlier callus senescence after growth had ceased but did not affect callus growth or root formation. Light‐induced senescence was prevented by a high cytokinin concentration.
THE EFFECTS OF HORMONES UPON THE DEVELOPMENT OF EXCISED FLORAL BUDS OF AQUILEGIA
Authors: Bilderback David E.
Published: January 2018

Young excised floral buds of Aquilegia were grown on defined medium containing kinetin, indoleacetic acid (IAA), or gibberellic acid (GA3). Only when 10−6 or 10−7 m kinetin was added to the basal medium was there a significant increase in the number of initiated whorls of primordia. Buds on the basal medium or on medium with IAA or GA3 failed to initiate carpels. On medium with 10−6 or 10−7 m kinetin, buds successfully initiated a normal whorl of five carpels. A high level of inorganic nitrogen was also required for the initiation of carpels. With 10−5 m kinetin, individual buds initiated from 6–18 carpels. Staminodial primordia of these buds were replaced with carpels, or the floral apex enlarged to accommodate a single whorl of many carpels. Kinetin did not support the further differentiation of the floral organs. Sepals, petals, and carpels did differentiate on medium with GA3, but stamens aborted. However, on medium with GA3 and kinetin, stamen primordia differentiated into short filaments and anthers. Further unknown growth factors appear to be required for the complete differentiation of floral primordia into mature organs.
STRUCTURE OF THE ROYAL ANN CHERRY CUTICLE AND ITS SIGNIFICANCE TO CUTICULAR PENETRATION
Authors: Wilson L. A. , Beavers D. V. , Cain R. F.
Published: January 2018

The structure of the Royal Ann cherry cuticle (Prunus avium L.) was determined and interpreted in the light of its possible significance to cuticular penetration by a SO2‐calcium bisulfite brine. The morphology of the cuticle was determined by standard histological and histochemical techniques. The surface structure of the cuticle was found to have a smooth to granular sheet or layer of surface wax, which when removed revealed a porous sponge‐like surface. The cuticular surface showed intermittent birefringence, which increased as the fruit matured. Ectodesmata were found to occur over anticlinal walls and in guard cells on both sides of the fruit, with more on the side opposite the suture. Both sides had stomata with more occurring on the suture side. Secondary bleaching was found to alter the structure and permeability of the cuticle.
GROWTH AND DEVELOPMENT OF CULTURED RADISH ROOTS
Authors: Webster Barbara D. , Radin John W.
Published: January 2018

Excised cultured roots of Raphanus sativus L. cv. White Icicle elongate and produce a few lateral roots but do not increase in diameter. Lateral expansion is effected when both an auxin (indoleacetic acid or naphthaleneacetic acid) and a cytokinin (benzyladenine) are applied at the cut end of the root. The growth regulator effects are apparent first in the pericycle and subsequently in the procambium. Both of these groups of cells divide, producing large numbers of secondary derivatives. The increase in number of cells is reflected in an increase in root diameter. When cultured roots are treated with auxin only, a limited number of pericycle cells divide and lateral roots develop. When roots are treated with cytokinin only, all pericycle cells divide and a multiseriate zone of pericycle‐derived cells develops. The procambium is not markedly affected by application of a single growth regulator. The distinct and separable responses of pericycle cells to different regulators suggest that the pericycle can be characterized in a functional, as well as a topographic, sense.
SYSTEMATIC STUDIES IN THE LEAF ANATOMY OF PALM GENUS SYAGRUS
Authors: Glassman S. F.
Published: January 2018

A systematic survey of the leaf anatomy of 51 taxa in the palm genus Syagrus was made. Cross sections of the middle pinnae of each taxon were embedded, cut, stained, and mounted on slides. Criteria used to distinguish species were based mainly on differences in the laminar surface and hypodermis: frequency and location of various sized veins; frequency, shape, and location of nonvascular fibers; size and shape of midrib and main vascular bundle; and size and shape of expansion cell tissue. The included key to the species employs mostly these characteristics. Each taxon is listed under subgenera and sections in the order presented in a previous article, where gross morphology was used as the basis of classification. Relationships between species of each subgenus and section are discussed in terms of the original arrangement of each group and needed changes. It is significant that certain evolutionary sequences have become unfolded which were not apparent by use of morphological characters alone. Although all relationships have not been completely worked out, this survey has resulted in a revision of my original classification of the genus Syagrus and at the same time has also corroborated certain alignments of species previously based on gross morphology.
CYTOTAXONOMY OF THREE SONCHUS SPECIES
Authors: Hsieh Tsun‐Shih , Schooler A. B. , Bell Allyn , Nalewaja John D.
Published: January 2018

All hybrid plants from interspecific crosses among the three species, Sonchus asper (L.) Hill, S. oleraceus L., and S. arvensis L., were male‐sterile, but the progeny of the cross S. arvensis X S. oleraceus and reciprocal cross produced seed after backcrossing to the male parent. Hybrid plants from crosses between S. oleraceus and S. asper lacked vigor. Cytological data indicated that S. arvensis has one genome in common with S. asper and that S. oleraceus is an autotetraploid (2n = 36) with no genomes in common with S. arvensis or S. asper.
THE ORIGIN OF AGROPYRON LEPTOURUM
Authors: Dewey Douglas R.
Published: January 2018

Colchicine‐induced amphiploids, 2n = 42, of diploid Agropyron libanoticum Hack., 2n = 14, X tetraploid A. caninum (L.) Beauv., 2n = 28, were morphologically and cytologically similar to A. leptourum (Nevski) Grossh., 2n = 42. Both A. leptourum and the induced amphiploids were self‐fertilizing. The induced amphiploids crossed readily with A. leptourum and gave rise to partially fertile hexaploid hybrids. Chromosome pairing in the hybrids averaged 0.60I, 18.29II, 0.36III, 0.58,v, 0.02v, and 0.22VI in 90 diakinesis or metaphase‐I cells. The genomes of the induced amphiploids are essentially homologous with those of A. leptourum except for two or more reciprocal translocations. The morphological, cytological, fertility, and crossing data provide conclusive evidence that A. libanoticum and A. caninum, or their close relatives, are the parents of A. leptourum. The genome formulas of A. libanoticum, A. caninum, and A. leptourum may be written as SS, SxSxHxHx, and SSSxSxHxHx, respectively, where S is the basic A. libanoticum genome and H is a genome derived from Hordeum.
THE ANNUAL RHYTHM OF CAMBIAL ACTIVITY IN TWO WOODY SPECIES OF THE CHILEAN “MATORRAL”
Authors: Aljaro María E. , Avila Guacolda , Hoffmann Alicia , Kummerow Jochen
Published: January 2018

The annual rhythm of cambial activity is compared in Proustia cuneifolia and Acacia caven, two typical shrubs of the “matorral” in the semiarid region of central Chile. Proustia, a drought deciduous shrub, shows a typical desert cambial rhythm, highly sensitive to rainfall. The growth activity of this species is limited to the periods of adequate moisture. Acacia is an evergreen whose cambial activity is observed almost throughout the year; it is not synchronous with rainfall. Adaptation in this species seems to consist in developing long roots able to tap underground water. These results indicate that both shrubs, although growing together, have different adaptive strategies to the same xerophytic conditions.
THE EFFECT OF ENVIRONMENTAL PARAMETERS ON THE GERMINATION, GROWTH, AND DEVELOPMENT OF SUAEDA DEPRESSA (PURSH) WATS
Authors: Williams Michael D. , Ungar Irwin A.
Published: January 2018

A study was made to determine the effect of environmental parameters on the germination, growth, and development of Suaeda depressa (Pursh) Wats. Germination tests showed that seeds germinated in solutions containing up to 4 % NaCl with no toxic effects indicated after treatment with distilled water. The rate of germination and the percentage germination decreased with increased salinity. The effect of environmental parameters on growth was measured by shoot height, side shoot development, leaf length, and dry weight. Growth was greatest in 1 % NaCl solutions with adequate available nitrogen. With increased salinity and low available nitrogen levels plant growth decreased. A 10‐hr photoperiod stimulated immediate floral induction. Although flowering and completion of the life cycle occurred in solutions containing up to 4 % NaCl, increased salinity decreased the rate of floral induction and the dry weight of flowers and fruit produced. This study indicates that environmental parameters such as salinity, available nitrogen, and photoperiod can create a variety of growth forms, causing taxonomic confusion.
CYTOKININ‐GIBBERELLIN REGULATION OF SHOOT DEVELOPMENT AND LEAF FORM IN TOBACCO PLANTLETS
Authors: Engelke Alvin L. , Hamzi Hamzi Q. , Skoog Folke
Published: January 2018

Callus and plantlets derived from callus cultures of Nicotiana tabacum var. Wisc. #38 were grown on medium containing serial combinations of gibberellic acid (GA3) and the cytokinin 6‐(3‐methyl‐2‐butenylamino)purine (2iP). Increasing levels of both growth substances resulted in the production of greater amounts of both callus and shoot tissue. More buds were induced when the cytokinin level was increased, and this effect was counteracted by raising the GA3/2iP ratio. Furthermore, the size and form of the shoots depended on the GA3/2iP ratio. High ratios resulted in tall, spindly plants with narrow leaves while low ratios resulted in short shoots with rounded leaves.
EFFECTS OF NEAR ULTRAVIOLET AND VISIBLE RADIATIONS ON CELL CYCLE KINETICS IN EXCISED ROOT MERISTEMS OF PISUM SATIVUM
Authors: Brown Susan J. , Klein Richard M.
Published: January 2018

Near‐ultraviolet and visible radiations increased the duration of the mitotic cycle in excised pea root meristems primarily by lengthening the duration of the pre‐DNA synthetic period (G1). All radiations tested shortened the duration of the post‐DNA synthetic period (G2). The most pronounced effects were exhibited by green radiation, which lengthened the duration of the cell cycle, G1, DNA synthesis (S), and mitosis (M), and shortened the duration of G2. Progression of cells arrested by starvation in G1 and G2 into DNA synthesis and mitosis was also affected by light treatments. Green radiation appeared to arrest a group of cells in DNA synthesis as well as in G1 and G2. Meristems receiving green and near‐ultraviolet radiations exhibited the most rapid progression of G1 cells through S and G2.
FOLIAR INITIATION AND THE FATE OF THE DWARF‐SHOOT APEX IN PINUS MONOPHYLLA
Authors: Gabilo Emerenciana M. , Mogensen H. Lloyd
Published: January 2018

The dwarf‐shoot apex of Pinus monophylla has a cytohistological zonation typical of pines. Cataphylls are initiated by this apex both before and after the dormant winter period. The needle is initiated in the spring of the same season in which it matures. The cytological details of cataphyll initiation are identical to that of needle initiation; however, the two primordia can be distinguished very early on the basis of their shape and direction of growth. After needle initiation the stem apex becomes inactive, is crowded to one side, and eventually disappears as the base of the needle enlarges. The results of the present work are discussed in relation to earlier conflicting interpretations regarding needle initiation and the subsequent existence of the dwarf‐shoot apex of P. monophylla.
INDUCTION OF MORPHOGENETIC CHANGES AND ACCELERATION OF LEAF INITIATION BY GIBBERELLIC ACID IN XANTHIUM PENNSYLVANICUM
Authors: Maksymowych R. , Maksymowych A. B.
Published: January 2018

One application of gibberellic acid (GA3) to young internodes significantly accelerated the rate of leaf initiation and caused an increase in the number of internodes in shoots of Xanthium pennsylvanicum. The average duration of one plastochron was reduced from 3.3 to 1.9 days. The rate of growth of the GA3‐treated internodes, and also of those positioned above and below, was at least twice that of the control. It appeared that the growth substance was translocated both acropetally and basipetally from the locus of application and that it significantly accelerated the rate of stem elongation. Gibberellic acid also had a pronounced morphogenetic effect on the leaves. It induced the development of lanceolate leaves instead of typical deltoid leaves. The area and the leaf length of the treated plants were both significantly reduced. Each response may be regulated by increasing or decreasing the concentration of gibberellic acid. The induced morphogenetic changes were not permanent. A reversion to the original condition was noticeable about 8 wk after treatment.
SOME CHEMOSYSTEMATIC ASPECTS OF THE AUDOUINELLA (ACROCHAETIUM‐RHODOCHORTON) COMPLEX
Authors: Richardson Norman , Mallery Charles H.
Published: January 2018

The total soluble protein, biliproteins, and esterase patterns from polyacrylamide discontinuous pH gel electrophoresis for three clones ofRhodochorton purpureumand three identified species ofAcrochaetiumare described. Absorption spectra of biliproteins are presented. Inter and intraspecific genetic affinities represented by electrophoretic protein patterns within theAudouinella (Acrochaetium‐Rhodochorton) complex are discussed. Problems of speciation within the complex are considered and the authors support the suggestions of Drew that a single genus be designated to represent the complex and the suggestion by Woelkerling that the genusAudouinellarepresent the sexually reproducing members of the complex.
GRASS LEAF ULTRASTRUCTURAL VARIATIONS
Authors: Johnson Clement , Brown Walter V.
Published: January 2018

The results of an ultrastructural examination of leaf anatomy and cytology of plastids of both non‐Kranz and Kranz grasses are presented. Variations of Kranz anatomy examined include agranal and two granal conditions of kranz‐cell chloroplasts, details of the two typical parenchyma sheaths of Aristida, and the “distinctive cells” of species of some small panicoid tribes. These conditions are discussed in relation to C4 photosynthesis, evolution, and classification.
ULTRASTRUCTURAL ASPECTS OF SHOOT INITIATION IN TOBACCO CALLUS CULTURES
Authors: Ross Malcolm K. , Thorpe Trevor A. , Costerton J. William
Published: January 2018

An ultrastructural investigation of shoot initiation in tobacco (Nicotiana tabacum L. var. W. 38) callus cultures was made. Zones of preferential division were observed in the basal portion of the tissue by eight days in culture and these led, sequentially, to meristemoids, primordia, and shoots. During the initial stages of meristemoid formation, protein inclusions and large accumulations of plastid starch were present in the cells, while vacuoles were filled with membranous and cytoplasmic protrusions. At later stages of meristemoid development, these features were not observed in the cells, which were also smaller in size and possessed numerous small, peripheral vacuoles. It appears that the membranous and cytoplasmic protrusions are involved in vacuolar reduction during meristemoid formation. It would also appear that the storage materials supply the energy and other reserves needed for the organogenetic process. By contrast, tissue cultured under nonshoot‐forming conditions and nonmeristemoid regions of shoot‐forming tissue remained parenchymatous over the same time period.
FERTILE CONIFEROPHYTE REMAINS FROM THE LATE TRIASSIC DEEP RIVER BASIN, NORTH CAROLINA
Authors: Delevoryas T. , Hope R. C.
Published: January 2018

Seed cones (Compsostrobus neotericus gen. et sp. nov.), pollen cones, and vegetative remains of coniferophytes occur in Upper Triassic rocks of the Deep River Basin (Pekin Formation) of Central North Carolina. Seed cones have spatulate ovuliferous scales, each with two ovules and subtended by an elongated bract with an attenuate tip. Cuticle of seed cones resembles that of leaves on vegetative axes. Slender leaves are borne along two sides of the axis. Pollen cones have helically arranged microsporophylls, each with two abaxial sporangia bearing pollen grains of the Alisporites type. Seed cones, pollen cones, and vegetative remains suggest a coniferophyte very modern in aspect.
THE “PALMELLOID” STATE IN A BLUE‐GREEN ALGA, ANABAENA SP. I. PRELIMINARY REPORT
Authors: Bausor S. C. , Agona John L.
Published: January 2018

The development of a “palmelloid” phase was studied in an adventive growth of a species of the blue‐green alga Anabaena sp. and in culture of the same strain. The primary change from its characteristic filamentous structure was the separation of the cells from one another. This was accompanied by the excessive production of capsular slime in which the separated cells were arranged at random. Associated with this were a gross change in cytology and a change in shape of cell from spheroidal to enlarged ellipsoidal. Fresh culturing of palmelloid cells resulted in the resumption of the typical filamentous growth, which in time reverted to the palmelloid phase.
ELECTRON MICROSCOPY OF PHIALIDES AND CONIDIOGENESIS IN TRICHODERMA SATURNISPORUM
Authors: Hammill Terrence M.
Published: January 2018

Each phialide had a thick‐walled neck region located immediately below a light microscopically inconspicuous collarette. The thickened wall of the phialide neck was multilaminate, with layers of different electron transmission properties. A developmental stage in the formation of the first conidial initial was observed. Conidial initials blew out through the thickened neck region, increased in size, and were eventually delimited by centripetally developing septa. Mature, winged conidia had an electron‐opaque outer wall layer and an electron‐transparent inner wall layer. The wing was formed by separation of these outer and inner wall layers and buckling or wrinkling of the outer layer. As early as they could be discerned, conidial initials had developed the electron‐opaque wall layer which characterized mature conidia. Each conidium‐delimiting septum became bilayered; the upper layer formed part of the conidial base, and the lower layer became a portion of the wall of the next conidial initial. Phialides lacked an electron‐opaque wall layer, and they possessed areas of abundant rough endoplasmic reticulum, as well as free ribosomes. Lipid globules were also abundant, especially in conidia. The distinction between phialides and annellides was questioned.
LOCALIZATION OF DEHYDROGENASE AND ACID PHOSPHATASE IN THE ABSCISSION ZONE OF BEAN LEAVES
Authors: Poovaiah B. W. , Rasmussen H. P.
Published: January 2018

Leaf abscission in Phaseolus vulgaris L. cv. ‘Contender’ is associated with enzymatic changes during and prior to separation. Deblading resulted in a localized increase in dehydrogenase and acid phosphatase in the abscission zone. Increased enzyme activities were observed 24–48 hr after deblading. In debladed plants separation was complete in 6–8 days. At separation, dehydrogenase activity appeared to decrease and localization was specific to the protective layer, while the petiole side had no activity. In contrast, acid phosphatase activity was observed in some layers of cells on the petiole side after separation. Ethylene treatment promoted abscission and separation occurred in 24–48 hr in both debladed and intact plants. No protective layer was formed during ethylene‐induced abscission. Enzymatic changes similar to those observed in debladed control plants were observed with ethylene treatment. Ethylene induced an additional abscission layer between the pulvinus and petiole, where an abscission layer normally does not form. In this ethylene‐induced abscission layer, similar enzyme activities were detected.
DIFFERENTIATION, ORGANOGENESIS, AND THE TECTONICS OF CELL WALL ORIENTATION. II. SEPARATION OF STRESSES IN A TWO‐DIMENSIONAL MODEL
Authors: Lintilhac Philip M.
Published: January 2018

This paper describes a polarographic technique for the separation of tension and compression stresses in a two‐dimensional plastic model of a sectioned cotton ovule. Compression and tension stress trajectories in the model comprise two families of lines which are mutually perpendicular and which, in the “nucellar” region of the model, coincide with cell wall patterns seen in sectioned ovules. This arrangement of stresses is demonstrated, by direct manipulation of the model, to be dependent on the pressure of the integuments. The integuments insure that compressive stresses generated during the growth of the nucellus do not collapse the embryo sac but pass around it, leaving it as a compression‐free space within the growing ovule.
NOVEL FLAVONOIDS AND RETICULATE EVOLUTION IN THE PHLOX PILOSA–P. DRUMMONDII COMPLEX
Authors: Levy Morris , Levin Donald A.
Published: January 2018

The nonanthocyanin flavonoids of the diploids Phlox pilosa ssp. pilosa and P. drummondii ssp. mcallisteri and their putative allotetraploid derivatives P. aspera and P. villosissima were characterized by chromatographic and spectrophotometric analyses. Synthetic F1 diploid hybrids were also examined. All but one of the compounds encountered were glycoflavone (C‐glycosyl) derivatives of either apigenin or luteolin. Although some compounds were present in all four taxa, most were species‐specific. Together, the diploids exhibited 15 different flavonoids. Half of each tetraploid ensemble was composed of novel flavonoids, compounds not manifest in either diploid ancestor. In total, the tetraploids produced seven different novel flavonoids. Five novel compounds differed from particular diploid compounds only in number or kind of oxygen‐linked sugar substituents. Ostensibly, these five are either identical to diploid biosynthetic intermediates or share common precursors with related diploid end products. The mode of origin of all novel compounds is discussed.
EFFECT OF 4'‐CHLOROGLUTARANILIC ACID ON GROWTH AND DEVELOPMENT OF SUNFLOWER SEEDLINGS
Authors: Larsen Stephen P. , Scholes Vernon P. , Skinner Charles G.
Published: January 2018

The potential growth‐regulating properties of 4'‐chloroglutaranilic acid (CGA) as well as oxygen and nitrogen isosteres were examined in whole‐plant bioassay systems utilizing sunflower seedling (Helianthus annuus L.). Test systems included both soil‐grown plants and hydroponic studies. Foliar applications of CGA produced growth inhibition which was detectable within 24 hr and which persisted for at least 30 days. Direct application to roots produced a growth inhibition which was 15% greater than foliar applications. Foliar or root application at 10‐5 m or greater concentrations produced gross changes in leaf morphology. Total plant‐height inhibition was principally associated with stem growth in an area located between primary leaves and the shoot meristem. CGA was found to be 32 % less active than IAA as a growth promoter, but was 76 % more active than IAA as a growth inhibitor; the most severely affected organ was the leaf and the least affected was the root system. Leaves from soil‐grown plants treated wth a 10‐3 m foliar application of CGA possessed several abnormalities. These included an increase in thickness and dry weight, a reduction in chloroplast starch vacuoles, extractable starch, soluble hexoses, and soluble proteins.
ONTOGENY OF FOLIAR DIAPHRAGMS IN TYPHA LATIFOLIA
Authors: Kaul Robert B.
Published: January 2018

Morphogenetic pulsations in the intercalary meristem of the leaf of Typha latifolia (Typhaceae) produce regular alternating sequences of vascular and stellate‐celled diaphragms separated at first by rib‐meristem derivatives. The collapse of these derivatives in the region of elongation in and above the intercalary meristem, and the separation of the diaphragms from each other, produce a mature compartmentalized leaf, the compartments bridged by porous diaphragms but separated from each other by rigid vascularized partitions.
PHOTOSYNTHESIS IN THE ANOMALOUS SECONDARY WOOD OF ATRIPLEX CONFERTIFOLIA STEMS
Authors: Wiebe H. H. , Al‐Saadi H. A. , Kimball S. L.
Published: January 2018

The anomalous secondary wood of A triplex confertifolia stems consists of vascular strands of xylem, phloem, and parenchyma embedded in fiberous conjunctive tissue. The included parenchyma contains chloroplasts and is capable of photosynthesis, as measured by14CO2 uptake by wood in the light.
ANATOMY AND FINE STRUCTURE OF THE MISTLETOE HAUSTORIUM (PHTHIRUSA PYRIFOLIA). I. DEVELOPMENT OF THE YOUNG HAUSTORIUM
Authors: Dobbins David R. , Kuijt Job
Published: January 2018

The anatomy and fine structure of the young primary haustorium of Phthirusa pyrifolia (H.B.K.) Eichl. were studied before penetration into the host. The simple internal organization (epidermis, hypodermis, and core parenchyma) which characterizes the radicular disc at germination becomes extremely complex, especially at the distal end of the disc during haustorial development. The epidermis in the area of contact with the host surface develops into an intricate cell zone consisting of lobed and tubular portions. The tubular portions consist of finger‐like projections that entwine and form bulbous tips at the contact surface. The tubular portions have unusual wall thickenings while the bulbous tips have exceedingly thin distal walls which possibly break, releasing their contents onto the host's surface. The collapsed layers characteristic of Santalalean haustoria seem to be a result of internal pressures caused by division and expansion of epidermal cells and core parenchyma. Various unusual ultrastructural features are described from the hypodermis, core parenchyma, and contact zone. Particularly striking, but yet unidentified, is a fibrillar material which often completely fills the cells of the core parenchyma in later stages of development.
NONHOMOLOGOUS CHROMOSOME PAIRING IN THE FERN CERATOPTERIS
Authors: Klekowski Edward J. , Hickok Leslie G.
Published: January 2018

The homosporous fern Ceratopteris thalictroides forms completely homozygous offspring sporophytes in one generation of selfing. Such homozygotes do not breed true and can exhibit structural heterozygosity for chromosomal mutations in some meiocytes. This is due to occasional nonhomologous (presumably homoeologous) chromosome pairing at meiosis in these polyploid ferns.
CONTRIBUTION TOWARD A MONOGRAPH OF RAMARIA. I. SOME CLASSIC SPECIES REDESCRIBED
Authors: Petersen Ronald H.
Published: January 2018

Clavaria flavescens, C. flava, C. aurea, C. pallida, and C. rubella, species originally described by J. C. Schaeffer and currently placed in Ramaria, are reexamined and redescribed in modern terms following studies of original literature and specimens from type localities.
ULTRASTRUCTURAL AND PHYSIOLOGICAL DIFFERENCES IN SOYBEANS WITH GENETICALLY ALTERED LEVELS OF PHOTOSYNTHETIC PIGMENTS
Authors: Crang Richard E. , Noble Reginald D.
Published: January 2018

Soybeans displaying incomplete dominance for leaf pigmentation possess chloroplasts with characteristic shape and organization of photosynthetic membranes. The chloroplasts of light green plants lack grana typical of dark green or a field type (Beeson) but normally possess doubled thylakoids. Achlorophyllous lethal yellow plants have thylakoids reduced to single spiralled membranes. The yellow plants lack a waxy cuticle over the leaf surface which is characteristic of all other soybeans examined, and they lack catalase activity in microbodies. Photosynthetic rates in the light green plants are at least as high as in the fully pigmented ones and photorespiration levels are not significantly different. Thus, in light green plants greater efficiency of enzymatic processes in photosynthesis apparently offsets the inhibitory activities associated with photorespiration. Single allele alterations from dark green to light green and light green to lethal yellow appear to alter a variety of structures and functions.
AXILLARY AND DICHOTOMOUS BRANCHING IN THE PALM CHAMAEDOREA
Authors: Fisher Jack B.
Published: January 2018

In both Chamaedorea seifrizii Burret and C. cataractarum Martius each adult foliage leaf subtends one axillary bud. The proximal buds in C. seifrizii are always vegetative, producing branches (= new shoots or suckers); and the distal buds on a shoot are always reproductive, producing inflorescences. The prophyll and first few scale leaves of a vegetative branch lack buds. Transitional leaves subtend vegetative buds and adult leaves subtend reproductive buds. Both types of buds are first initiated in the axil of the second or third leaf primordia from the apex, P2 or P3. Later development of both types of bud tends to be more on the adaxial surface of the subtending leaf base than on the shoot axis. Axillary buds of C. cataractarum are similarly initiated in the axil of P2 or P3 and also have an insertion that is more foliar than cauline. However, all buds develop as inflorescences. Vegetative branches arise irregularly by a division of the apex within an enclosing leaf (= P1). A typical inflorescence bud is initiated in the axil of the enclosing leaf when it is in the position of P2 and when each new branch has initiated its own P1. No scale leaves are produced by either branch and the morphological relationship among branches and the enclosing leaf varies. Often the branches are unequal and the enclosing leaf is fasciated. The vegetative branching in C. cataractarum is considered to be developmentally a true dichotomy and is compared with other examples of dichotomous (= terminal) branching in the Angiospermae.
EFFECTS OF LEAF EXCISION ON FLOWERING OF XANTHIUM APICAL BUDS IN CULTURE UNDER INDUCTIVE AND NONINDUCTIVE PHOTOPERIODS
Authors: Jacobs William P. , Suthers Hannah B.
Published: January 2018

Apical buds of Xanthium were grown in aseptic culture under short‐day cycles known to induce flowering in the intact plants or under “light‐break” conditions known to prevent flowering. The total light provided in each 24‐hr cycle was the same under the two photoperiods. Various numbers of leaves were excised from the apical buds. Excision of leaves did not change the response to photoperiod: even with all leaves excised the apical buds cultured under short‐day conditions reached the same average floral stage as the control buds, and those under light‐break conditions all remained vegetative. Fresh weight was not significantly changed by the excisions, either. However, excision of the young leaves resulted in an increase in the number of new leaves developed by the apical bud during the two‐week culture period.
VESSELS IN JUNCALES: II. CENTROLEPIDACEAE AND RESTIONACEAE
Authors: Cheadle Vernon I. , Kosakai Hatsume
Published: January 2018

The occurrence and specialization of vessels in 6 genera and 14 species of Centrolepidaceae and 25 and 72, respectively, of Restionaceae are described. Those in Anarthriaceae (1 and 3) and Ecdeiocoleaceae (1 and 1), newly separated from Restionaceae, were also examined. Vessels in Ecdeiocolea are highly specialized; those in Centrolepidaceae are relatively primitive. Vessels in Restionaceae and Anarthriaceae are intermediate. Vessels in Cyperaceae and Gramineae are compared with those in Juncales in a review of vessels in Glumiflorae. Thurniaceae has most primitive vessels on the average, Juncales has more primitive vessels in leaves and inflorescence axes than does Cyperales; the opposite is true for roots, rhizomes and stems. Vessels in Graminales on the average are much more specialized than those in Cyperales and Juncales.
INTERCALARY MERISTEMATIC ACTIVITY IN THE SPOROPHYTE OF FUNARIA (MUSCI)
Authors: French J. C. , Paolillo D. J.
Published: January 2018

Marking procedures were combined with anatomical techniques to establish that in Funaria (1) the apical region does not act as an apical meristem contributing to seta growth, and (2) the subapical region contains an intercalary meristem the derivatives of which account for the elongation of the seta. In sporophytes that are 8 mm long there is a distinctive difference in the pattern of cell division in the apical and subapical regions. Large, undivided endothecial cells exist in the apical region, and a central strand of elongated cells occupies the analogous position in the subapical region. The apical region is earmarked to form the operculum and spore sac and part of the apophysis. There is an ontogenetic continuity between the seta and the lower portion of the apophysis, but the uppermost cells of the subapical region do not contribute to seta formation. Instead, these cells and those at the base of the apical region form a transitional zone between apical and subapical influences, and they account for most of the stomates that develop on the apophysis.
THE POLLINATION ECOLOGY OF ASTRAGALUS CIBARIUS AND ASTRAGALUS UTAHENSIS (LEGUMINOSAE)
Authors: Green Thomas W. , Bohart George E.
Published: January 2018

Astragalus cibarius and A. utahensis are common perennial species of a widespread legume genus. The pollination of Astragalus has been briefly discussed in the literature, but little work has been done on species in the intermountain West. This study was conducted from 1970–1973 in Utah with mixed and single species populations. The flowers of both species were homogamous and papilionaceous, but the species were different as to color, size, and ultraviolet reflectance. Astragalus cibarius usually flowered 10 days ahead of A. utahensis, but both species flowered earlier than most other plants in the community. Bagging experiments indicated both species were strongly allogamous. Exclosure studies indicated both species relied on insects as pollen vectors. Of the 44 insect species which were observed visiting flowers, only 14 carried Astragalus pollen, and the pollinator fauna varied between study sites. Pollen quantities and distributions on Diptera and Coleoptera indicated a poor potential for pollination. Floral structure, pollen distribution and quantity, and behavior implied that large bees of the families Apidae and Anthophoridae were the primary pollinators. These bees visited only one species of Astragalus when the plants occurred in mixed populations; this constancy may have been related to relative flower abundance. Non‐pollinating floral foragers affect other phases of Astragalus life history.
DIFFERENTIAL MORTALITY AMONG COHORTS IN A POPULATION OF ACER SACCHARUM (ACERACEAE) SEEDLINGS
Authors: Mulcahy David L.
Published: January 2018

Theoreticians have suggested that genetic changes in long‐lived perennial species may show a lag in response to selective pressures. If this suggestion is correct, then these populations should contain subpopulations adapted to dissimilar environments. The present study, employing data on age distributions and gel electrophoresis, provides some evidence for the existence of these genetically differentiated subpopulations among seedlings of Acer saccharum.
CHROMOSOME NUMBERS FOR NORTH AMERICAN EUPHORBIACEAE
Authors: Urbatsch Lowell E. , Bacon John D. , Hartman Ronald L. , Johnston Marshall C. , Watson Thomas J. , Webster Grady L.
Published: January 2018

Chromosome number determinations are reported for 101 collections distributed among 54 species of the North American Euphorbiaceae. First counts are presented for 44 species. When appropriate, systematic discussions regarding chromosomal information are included. Camera lucida drawings are published for previously undocumented chromosome reports.
DIFFERENTIAL SENSITIVITY OF “DOUBLE” AND “SINGLE” FLOWERS OF NIGELLA DAMASCENA (RANUNCULACEAE) TO EMASCULATION AND TO GA3
Authors: Greyson Richard I. , Raman K.
Published: January 2018

In Nigella damascena “double” flower is inherited as a single‐gene recessive to “single” flower. Early emasculation of “double” flowers greatly inhibits gynoecium development and, to a lesser degree, development of sepals and bracts. No comparable inhibition of gynoecia was induced in “single” flowers though some sepal and bract inhibition was detected. A differential nutritional requirement for organ initiation on cultured flower apices was also detected. Apices of both varieties initiated stamens and carpels if kinetin was added to the basal medium. However, in the absence of kinetin, GA3 was required for organ initiation in “doubles” but completely inhibited stamen initiation in “singles.” Both these differential effects are thought to reflect rather different patterns of gibberellin metabolism in the two genetic strains.
DISTRIBUTION OF KRANZ SYNDROME AMONG ASTERACEAE
Authors: Smith Bruce N. , Turner B. L.
Published: January 2018

A broad survey of the Asteraceae, involving visual characters, was undertaken to ascertain the occurrence of possible Kranz‐type (C4) plants. One hundred and seven taxa representing 51 genera were examined by mass spectrometry for their 13C/12C ratios in dried leaf tissue. Species possessing the high 13C/12C ratio typical of the Kranz syndrome were found in genera belonging to the following tribes: Heliantheae (subtribe Coreopsideae)—Chrysanthellum (4 spp.), Eryngiophyllum (1 sp.), Glossocardia (1 sp.), Glossogyne (1 sp.), Isostigma (5 spp.); Tageteae—Pectis (21 spp.); and Helenieae—Flaveria (4 spp.). The only genus to possess both C3 and C4 species was Flaveria in which all but four species appear to possess a C3‐type metabolism. When appropriate, the phyletic input of these data is discussed.
DIFFERENTIATION OF INTRACAPSULAR CELLS IN THE SPOROPHYTE OF SPHAEROCARPOS DONNELLII
Authors: Kelley Carole B. , Doyle William T.
Published: January 2018

Ultrastructural and histochemical changes during intracapsular cell differentiation in the premeiotic sporophyte of the liverwort Sphaerocarpos donnellii Austin were studied. From an initially undifferentiated meristematic tissue, spore mother cells and nutritive cells become differentiated. The first indications of ultrastructural differentiation into two cell types are the accumulation of lipid within spherosomes and the occurrence of plastid tubules in the presumptive spore mother cells. Once differentiated the two cell types are clearly distinguishable on the basis of cytoplasmic vacuolation, stored food reserve, and cell and nuclear size. The mature spore mother cell contains many spherosomes, small vacuoles, starch‐containing plastids, and a large central nucleus. The mature nutritive cell, on the other hand, is extremely vacuolate and contains large, starch‐filled plastids, a few spherosomes, and a small nucleus. A previously undescribed type of cell was observed in developing sporophyte capsules. This cell is located peripherally in the capsule and degenerates during differentiation of spore mother cells and nutritive cells.
A TECHNIQUE FOR THE ANALYSIS OF EPISTATIC GENE ACTION I. THE METHOD OF ANALYSIS
Authors: Clevenger Sarah
Published: January 2018

The thirty‐two possible genic crosses involving two pairs of nonlinked genes were simulated. The anticipated progeny of each cross was analyzed according to each of the seven basic types of epistatic action. A key was devised to facilitate the recognition of genic action since most phenotypic progeny ratios are produced exclusively either by phenotypically similar parents or phenotypically dissimilar parents. Only ratios of 3:1, 2:1, and 1:1 can be produced by both types of parents.
CHROMOSOME NUMBERS IN THE GENUS ANTHURIUM
Authors: Sheffer R. D. , Kamemoto H.
Published: January 2018

Chromosome numbers were determined for 63 Anthurium species. Thirty‐eight of these were newly determined. Generally the present work confirmed existing chromosome counts when these were available for comparison. The most common somatic chromosome number found was 30, but counts ranged from 2n = 20 to 90. In a few instances conflicting counts were obtained. B chromosomes were found frequently in Sect. Cardiolonchium and varied in number from one to three. Four polyploid series were evident from all available counts: 20‐40, 24‐30‐48‐84, 28‐56 and 30‐60‐90‐ca 124. Most species were part of the polyploid complex based on 30. Although species were not observed with n = 5, 6 or 7, movement among the basic numbers was considered to have occurred at this level. The relationship among these basic numbers and n = 15 (x2) is still obscure.
DEVELOPMENTAL STUDIES IN PTYCHOSPERMA (PALMAE). I. THE INFLORESCENCE AND THE FLOWER CLUSTER
Authors: Uhl Natalie W.
Published: January 2018

This paper describes inflorescence structure, including organogenesis of the panicle and flower clusters and vasculature of flowering branches, for two species of Ptychosperma, a genus of arecoid palms. The inflorescence is an infrafoliar panicle with up to four orders of branches in a spirodistichous arrangement conforming to an irregular one‐half phyllotaxy. The primordium of the inflorescence is crescentic and the apex has two tunica layers, a group of central cells, and a rib meristem. The distal flower‐bearing parts or rachillae of all branches develop acropetally early in ontogeny and are vertically oriented in the bud. Although these rachillae terminate branches of different sizes and orders, they are similar in size and in number of flower clusters produced. Internodes and lower parts of branches develop later. Bracts of four types are produced: a prophyll and empty peduncular bract, bracts which subtend lateral branches, bracts subtending triads, and floral bracteoles. The prophyll and peduncular bracts are tubular and completely closed around all branches until about three months before the flowers reach anthesis. Bracts subtending lateral branches and those that subtend triads enlarge by small amounts of apical, adaxial, and marginal growth to cover subtended apices during early ontogeny, but are small to absent at maturity. Flower clusters are triads of two lateral staminate and a central pistillate flower. Organogenesis indicates that the triad is a sympodial unit. Flowers develop successively, each floral apex bearing a bracteole that subtends the next flower. The vasculature of the inflorescence may be divided into two systems. Bundles of the main axis extend acropetally into the vertically oriented branches as they are initiated and form a central cylinder of larger bundles in each branch. Flower clusters are supplied by a peripheral system of smaller bundles that develop later in relation to the developing floral organs. Bundles of the peripheral system branch frequently, but branching levels are irregular. The irregular branching of peripheral bundles appears related to the phyllotaxy of the flower clusters and the random right or left position of the first flower of the triad. The level of branching of a bundle may depend on the position of a floral primordium with respect to an existing procambial strand. Three (‐4) bundles supply each staminate flower and six (‐10) the pistillate flower. The histologically specialized inflorescence has stomata and contains abundant starch. Tannins and raphides, spherical silica bodies, and various forms of sclerenchyma appear in sequence and apparently provide support and protection during the long exposure of the branches.
INITIATION AND DEVELOPMENT OF ROOT NODULES OF CASUARINA (CASUARINACEAE)
Authors: Torrey John G.
Published: January 2018

Roots of seedlings of the “beefwood” tree, Casuarina cunninghamiana Miq. grown in nitrogen‐free nutrient solution were inoculated with a suspension prepared from crashed root nodules taken from mature plants. Marked deformation of root hairs was evident but no infection threads were observed in root hairs. The mode of infection remains undetermined. Root nodules were initiated within three weeks and thereafter numerous upward‐growing nodule roots developed from each nodule. Nodules in this symbiotic nitrogen‐fixing plant resulted from an infection caused by an unidentified actinomycete‐like soil microorganism. Anatomical analysis of nodule formation showed that nodules are the result of repeated endogenous lateral root initiations, one placed upon another in a complexly branched and truncated root system. The endophyte‐infected cortical tissues derived from successive root primordia form the swollen nodular mass. Nodule roots develop from nodule lobes after escaping from the initial inhibitory effects of the endophyte. Included is a discussion of the anatomical similarities between nodules of Casuarina which produce nodule roots and those of Alnus which form coralloid nodules usually lacking nodule roots.