bluuebunny/crossref_metadata_2025 huggingface dataset:
NATURAL HYBRIDS BETWEEN ORYZOPSIS AND STIPA. I. ORYZOPSIS HYMENOIDES × STIPA SPECIOSA
Authors: Johnson B. Lennart
Published: January 2018

Johnson, B. Lennart. (U. California, Los Angeles.) Natural hybrids between Oryzopsis and Stipa. I. Oryzopsis hymenoides × S. speciosa. Amer. Jour. Bot. 47(9): 736–742. Illus. 1960.—Spontaneous, sterile hybrids between Oryzopsis hymenoides and Stipa speciosa heretofore have been referred to O. bloomeri, which species in an earlier paper was shown to consist of a series of hybrids between O. hymenoides and various species of Stipa. On many morphological characters (O. hymenoides × speciosa) is intermediate between its parents and similar to the other hybrids formerly classed as O. bloomeri. It is distinct from the other hybrids on characters which reflect S. speciosa, except with respect to indument of the awn which is recessive. Somatic chromosome counts are: O. enoides, 48; S. speciosa, 64; hybrid, 56. Both parents exhibit regular bivalents at meiosis. The hybrid shows only occasional bivalents and mostly asynchronous splitting or random distribution of univalents at metaphase I. Pollen abortion is complete. No evidence of natural amphiploidy or introgression was found.
DEVELOPMENT OF THE LAMINA IN XANTHIUM ITALICUM REPRESENTED BY THE PLASTOCHRON INDEX
Authors: Maksymowych Roman , Erickson Ralph O.
Published: January 2018

Maksymowych, Roman (Villanova U., Villanova, Pa.), and Ralph O. Erickson. Development of the lamina in Xanthium italicum represented by the plastochron index. Amer. Jour. Bot. 47(6):51–459. Illus. 1960.—Xanthium plants were grown vegetatively, and leaves, whose developmental age was specified by a previously described leaf plastochron index (L.P.I.), were measured and studied histologically. Leaf initiation occurs before L.P.I.–6.0. Initiation of the lamina occurs at about L.P.I. –4.8, when the primordium is about 0.22 mm. long. Mitotic divisions in the marginal and plate meristems continue until about L.P.I. 1.7, when the leaf is about 37 mm. long, a period of about 23 days. Between L.P.I. 1.0 and 3.0, approximately, there is a rapid 4‐fold increase in thickness of the lamina, with development of the characteristic palisade and spongy mesophyll tissues. Virtually no further increase in thickness occurs after L.P.I. 4.0, but the lamina continues to increase in length until about L.P.I. 6.0, when it has reached a mature length of about 180 mm. A statistical analysis has been made of planes of division in the marginal meristem, which in some respects fails to support published histogenetic schemes for this meristem.
A REVISION OF ARIOCARPUS (CACTACEAE). I. THE STATUS OF THE PROPOSED GENUS ROSEOCACTUS
Authors: Anderson Edward F.
Published: January 2018

Anderson, Edward F. (Claremont Graduate School, Claremont, California.) A revision of Ariocarpus (Cactaceae). I. The status of the proposed genus Roseocactus. Amer. Jour. Bot. 47(7) : 582–589. Illus. 1960.—The proposed genus Roseocactus Berger is found to be a subgenus of Ariocarpus. The subgenera Ariocarpus and Roseocactus are basically similar in habitat, seedlings, presence of mucilage systems, tubercle structure, seed structure, fruiting habit, flower origin and structure, alkaloidal properties, trichomes, pollen grains, and chromosome number. They differ in flower color, presence or absence of an areolar groove, tubercle divergence, and trichome texture. A hypothesis is proposed to explain variations in the areoles. The differences in structure of mature tubercles are thought to be due to variability in the location of growth and elongation with respect to the floral and spinous areolar areas.
MICRURGICAL TECHNIQUES FOR NEUROSPORA
Authors: Wilson James F.
Published: January 2018

Wilson, James F. (Hartnell Coll., Salinas, Calif.) Micrurgical techniques for Neurospora. Amer. Jour. Bot. 48(1): 46–51. IIlus. 1961.—Procedures for carrying out micrurgical operations on the mold, Neurospora crassa, are described. These procedures include interstrain transfer of protoplasm, micro‐injection of fluids, excision and culture of injected cells. The special microtools and culture methods for these micrurgical procedures are discussed.
THE SEPARATION OF NINE SPECIES OF THE IRIDACEAE BY PAPER CHROMATOGRAPHY
Authors: Riley H. P. , Bryant T. R.
Published: January 2018

Riley, H. P., and T. R. Bryant. (U. Kentucky, Lexington.) The separation of nine species of the Iridaceae by paper chromatography. Amer. Jour. Bot. 48(2): 133–137, Illus. 1961.—Chromatograms were made from small pieces of the root tip of 9 species of 4 genera of the Iridaceae. Under ultraviolet light, the patterns of Watsonia ardernei and W. vanderspuyae were almost identical which suggests that they are closely related species. On the basis of chromatographic patterns, W. fourcadei apparently is not so closely related to them but is rather closely related to W. wilmaniae; W. pyramidata and W. wordsworthiana are less closely related to the other species. The patterns of Dietes grandiflora, Babiana bainesii and Sparaxis aureum are strikingly different from one another and from those of the species of Watsonia.
CYTOTAXONOMY OF LOWBUSH BLUEBERRIES IN EASTERN CANADA
Authors: Hall Ivan V. , Aalders Lewis E.
Published: January 2018

Hall, I. V., and L. E. Aalders. (Research Sta., Kentville, Nova Scotia.) Cytotaxonomy of lowbush blueberries in Eastern Canada. Amer. Jour. Bot. 48(3): 199–201. Illus. 1961.—The common lowbush blueberry of commercial fields in Eastern Canada, Vaccinium angustifolium Ait., is tetraploid (2n = 48). A new species, Vaccinium boreale, is similar to it but is diploid (2n = 24). The 2 species can be distinguished from each other on the basis of chromosome number, corolla length, pollen size, and degree of branching. Most vegetative characters of the 2 species overlap with varying environmental conditions, and their use for taxonomic purposes has led to confusion. V. boreale is found typically on exposed headlands in Newfoundland and has not been found in commercial fields outside that province.
FURTHER OBSERVATIONS ON THE STRUCTURE OF SELAGINELLITES CRASSICINCTUS
Authors: Leisman Gilbert A.
Published: January 2018

Leisman, Gilbert A. (Kansas State Teachers Coll., Emporia.) Further observations on the structure of Selaginellites crassicinctus. Amer. Jour. Bot. 48(3): 224–229. Illus. 1961.—Specimens of Selaginellites crassicinctus Hoskins and Abbott in coal balls from southeastern Kansas have yielded new information concerning the anatomy of this strobilus. The axis contains an exarch protostele apparently suspended in an air‐cavity by endodermal trabeculae. Sporophylls are attached in alternating whorls of 4 each. The strobilus is compared with modern Selaginella and a related compression fossil species.
GROWTH PATTERNS OF PEA SEEDLINGS IN DARKNESS AND IN RED AND WHITE LIGHT
Authors: Thomson Betty F. , Miller Pauline Monz
Published: January 2018

Thomson, Betty F., and Pauline Monz Miller. (Connecticut Coll., New London.) Growth patterns of pea seedlings in darkness and in red and white light. Amer. Jour. Bot. 48(3): 256–261. Illus. 1961.—Seedlings of peas were grown in vermiculite at 22°C. and exposed 16 hr. daily to red or white light or kept in darkness. Others were grown in soil in the greenhouse. Samples harvested daily to 16 days were dissected, the length of each internode and leaf measured and the total number of leaves and leaf primordia counted. The form of the stem apex and youngest primordia and interrodes is the same in light as in darkness. Leaf production is accelerated very slightly and the growth of leaves and internodes is decidedly accelerated by light. Leaf‐leaf, leaf‐internode and internode‐internode correlations indicate that the morphogenetic effect of light is limited to later stages of organ growth. Dry weight is consumed more rapidly in light than in darkness, probably because of more rapid growth and slightly greater amounts of respiring tissue in light‐grown plants.
THE STRUCTURE AND REPRODUCTION OF GLAPHYRYMENIA PUSTULOSA
Authors: Norris Richard E.
Published: January 2018

Norris, R. E. (U. Minnesota, Minneapolis.) The structure and reproduction of Glaphyrymenia pustulosa. Amer. Jour. Bot. 48(3): 262–268. Illus. 1961.—Specimens of Glaphyrymenia pustulosa, a red alga from Australia that has seldom been found, were collected recently. The specimens were examined particularly with respect to development of the vegetative tissues and the formation of the female reproductive apparatus and gonimoblast. The vegetative structure is primitive in the Kallymeniaceae and structural characteristics are present that are similar to the Cryptonemiaceae and Dumontiaceae. The female reproductive system has a monocarpogonial carpogonial branch apparatus and an auxiliary cell that is borne on a separate system that does not have a carpogonial branch. After fertilization, stages in the development of the gonimoblast are similar to those of Kallymenia and Pugelia.
SUBMICROSCOPIC STRUCTURE AND DEVELOPMENT OF THE CHLOROPLASTS OF PSILOTUM TRIQUETRUM
Authors: Sun C. N.
Published: January 2018

Sun, C. N. (Washington U., St. Louis, Mo.) Submicroscopic structure and development of the chloroplasts of Psilotum triquetrum. Amer. Jour. Bot. 48(4): 311–315. Illus. 1961.—Aerial stems and stem tips of Psilotum triquetrum were used for the study of the fine structure and development of chloroplasts. The chloroplasts of Psilotum are ellipsoidal, with a principal axis of approximately 13 μ and a short axis of approximately 3.6 μ. They are bounded by a well‐defined outer membrane which consists of 2 layers. Within the laminar system of the stroma, the lamellated grana appear as sharply defined regions. The grana are about 1–1.6 μ in diameter. They are distributed more or less uniformly throughout the entire chloroplast with the exception of a very narrow peripheral zone. Relatively large, osmiophilic globules occur in groups in the stroma. The development of the Psilotum chloroplast may be summarized as follows: (1) in the undifferentiated proplastid, vesicles occur; (2) lamellated layers are formed by the fusion of vesicles; (3) the lamellae multiply by a process of thickening and splitting; (4) the grana are differentiated within a certain area by heterogeneous deposition of material and by further cleavage of the lamellae. Osmiophilic globules are present throughout the developmental stages, and increase in number and size with increase in age of the chloroplast.
THE EIGHTY‐YEAR PERIOD FOR DR. BEAL'S SEED VIABILITY EXPERIMENT
Authors: Darlington H. T. , Steinbauer G. P.
Published: January 2018

Darlington, H. T., and G. P. Steinbauer. (Michigan State U., East Lansing.) The eighty‐year period for Dr. Beal's seed viability experiment. Amer. Jour. Bot. 48 (4): 321–325. 1961.—Seeds of 20 species of plants were buried 80 years ago on the Michigan State University campus. Bottles have been dug up periodically in the intervening years and the seeds tested for viability. A bottle representing the 80‐year period of burial was dug up this spring and the contents distributed uniformly on the surface of sterilized soil in the greenhouse. Of the 20 species whose seeds were buried in 1879, only 3 have survivors as viable seeds. These are the same 3 that had survived the 70‐year burial period, namely: curled dock, Rumex crispus; evening primrose, Oenothera biennis; and moth mullein, Verbascum blattaria. The low percentage survival of curled dock (2%) indicates that the longevity of the buried seeds of this species is nearing the end. The situation is more favorable for evening primrose, with 10% survival. The third, moth mullein, has about as many survivors as 10 years ago, a remarkably high figure of 70% viability. Since there has been no significant drop in viability of the buried seeds over the last 30 years, it seems highly probable that longevity of buried seeds of this species may extend over a century. A brief summary is given of the current status of the behavior of buried seeds, based on this and other buried seed experiments.
PHOTOINHIBITION OF STEM ELONGATION BY FULL SOLAR RADIATION
Authors: Lockhart James A.
Published: January 2018

Lockhart, James A. (U. Hawaii, Honolulu.) Photoinhibition of stem elongation by full solar radiation. Amer. Jour. Bot. 48(5): 387–392. Illus. 1961.—Stem growth response of ‘Pinto’ bean (Phaseolus vulgaris) to full solar radiation and to various degrees of shading has been studied. Maximum stem elongation occurred at light intensities of approximately 40,000 lux, under the conditions used here. Lower growth rates were found when light intensities were greater or less than this level. When the plants are saturated with gibberellin A3, stem growth is maximum at the highest light intensity, and less at all lower light intensities. Sucrose sprays promoted growth at low light intensities. Apparently, slower growth at low light intensities is due to a deficiency of photosynthetic products, while growth inhibition at high intensities is due to a deficiency of gibberellin. Growth of ‘Alaska’ peas, which are more nearly saturated with endogenous gibberellin, is much less inhibited by high light—or much less promoted by partial shading. This appears to be a general relationship. Dwarf Zea mays (d1), which is very deficient in gibberellin, responds markedly to shading, but the normal segregate (D1) responds little to shading. When the dwarfs are saturated with gibberellin they, too, respond little to shading. Experiments are presented indicating that the high‐intensity light inhibition of stem growth and low‐energy red light inhibition act on the same step in the gibberellin system.
EMBRYOGENY IN THE CALIFORNIA PEONIES WITH REFERENCE TO THEIR TAXONOMIC POSITION
Authors: Cave Marion S. , Arnott Howard J. , Cook Stanton A.
Published: January 2018

Cave, Marion S. (U. California, Berkeley), Howard J. Arnott, and Stanton A. Cook. Embryogeny in the California peonies with reference to their taxonomic position. Amer. Jour. Bot. 48(5): 397–404. Illus. 1961.—The embryogeny of Paeonia californica Nutt. ex T. and G. and P. brownii Dougl. ex Hook. is described. No cell wall is formed at the end of the first division of the zygote nucleus, but instead, a massive coenocytic proembryo is produced. This structure becomes cellular, and numerous embryo primordia form on its surface, one of which gains ascendancy over the others to form the embryo proper, consisting of root, shoot apex, epicotylar leaf primordium, and 2 cotyledons. The embryogeny of the California peonies is essentially similar to that of P. anomala, P. moutan, and P. wittmanniana described by Yakovlev and Yoffe, and does not support the contention of Murgai that in P. albiflora, P. actiflora, P. delavayi, and P. suffruticosa the coenocyte is a suspensor. It is suggested that the coenocytic embryos of gymnosperms and Paeonia represent a case of parallel evolution rather than that there is any implication of phylogenetic relationships between them.
CYTOLOGY OF SUPERNUMERARY CHROMOSOMES IN HAPLOPAPPUS SPINULOSUS SSP. COTULA
Authors: Li Ning , Jackson R. C.
Published: January 2018

Li, Ning, and R. C. Jackson. (U. Kansas, Lawrence.) Cytology of supernumerary chromosomes in Haplopappus spinulosus ssp. cotula. Amer. Jour. Bot. 48(5): 419–426. Illus. 1961.—The behavior of supernumerary chromosomes was investigated in 2 plants. In 1, the number of supernumeraries was highly variable in both somatic and meiotic cells, presumably as a result of somatic non‐disjunction. In the second plant, the number of supernumerary chromosomes was less variable, but an end‐to‐end association of a pair of supernumeraries and a regular bivalent was observed in a small percentage of the microsporocytes at zygotene and pachytene. This end‐to‐end association apparently resulted in a permanent fusion of the supernumerary and regular chromosome ends in some instances because the union persisted throughout both meiotic divisions. There was no evidence of normal pairing between the supernumeraries and regular chromosomes.
NUTRIENT REQUIREMENTS FOR IN‐VITRO GROWTH OF SPRUCE TISSUE
Authors: Steinhart C. E. , Standifer L. C. , Skoog F.
Published: January 2018

Steinhart, C. E., L. C. Standifer, Jr., and F. Skoog. (U. Wisconsin, Madison.) Nutrient requirements for in‐vitro growth of spruce tissue. Amer. Jour. Bot. 48(6): 465–472. Illus. 1961.—Callus derived from seedlings of Norway spruce has been cultured for 3½ yr on a medium supplemented with malt extract. The responses of the callus to auxin, kinetin, light intensity, and pH were determined. The malt extract employed was fractionated by various methods, and it was shown that the active fractions were generally ninhydrin positive. The free amino acid composition of the extract was determined. Malt extract could be replaced completely by casein hydrolysate. Arginine, glutamine, or urea, although less effective, also supported continuous growth of the callus. In contrast, NH4NO3 as a sole source of nitrogen failed to support growth. The same compounds that supported growth of the established strain of callus also stimulated initial formation of callus from seedlings. Inositol was the only vitamin that could be shown to stimulate callus growth. A synthetic medium has been developed for the cultures; it includes inorganic nutrients, naphthaleneacetic acid, kinetin, myo‐inositol, and either arginine or urea. Thiamin, choline chloride, and cystein are also added to the medium, although a requirement for the latter 2 of these 3 compounds has not been demonstrated.
EFFECTS OF PHOTOPERIOD AND KIND OF SUPPLEMENTAL LIGHT ON GROWTH, FLOWERING, AND STEM FASCIATION OF CELOSIA
Authors: Piringer A. A. , Borthwick H. A.
Published: January 2018

Piringer, A. A., and H. A. Borthwick. (U.S.D.A., Beltsville, Md.) Effects of photoperiod and kind of supplemental light on growth, flowering and stem fasciation of Celosia. Amer. Jour. Bot. 48(7): 588–592. Illus. 1961.—Four cultivars of Celosia argentea L. var. cristata were grown on photoperiods ranging from 8 hr to continuous light. Supplemental low‐intensity incandescent light was used to extend 8 hr of natural light and provide the given photoperiod. In all cultivars, short main stems occurred on photoperiods of 12 or fewer hours and long main stems, due to more nodes, on photoperiods of 16 or more hours. Flowering was a nonobligate short‐day response in all cultivars. Plants of certain cultivars tended to have shorter stems and flower later when 8 hr of fluorescent instead of incandescent light was used to provide the 16‐hr photoperiod. In 3 of the cultivars studied, photoperiods of 16 or more hours induced marked stem fasciation.
THE EFFECT OF BENZIMIDAZOLE ON CATION UPTAKE BY PLANT ROOTS
Authors: Klingensmith M. J.
Published: January 2018

Klingensmith, M. J. (Colgate U., Hamilton, N.Y.) The effect of benzimidazole on cation uptake by plant roots. Amer. Jour. Bot. 48(8): 711–716. Illus. 1961.—A number of benzazole compounds were examined for their effect on cation uptake. Benzimidazole was found to almost double the uptake of potassium by excised barley roots in a 6‐hr period. Chlorobenzimidazole also enhanced the absorption of potassium but not to the same extent. This stimulation of potassium accumulation was found to be insensitive to cyanide but was dependent on the temperature of the ambient solution. There was also an increased accumulation of potassium by roots of intact barley plants with benzimidazole treatment without interference with subsequent transport of the potassium. Benzimidazole also stimulated uptake of sodium and calcium by excised barley roots but not at identical levels. Results are discussed in the light of various theories of ion absorption.
CYTOGENETIC AND EVOLUTIONARY STUDIES IN SECALE. I. SOME NEW DATA ON THE ANCESTRY OF S. CEREALE
Authors: Khush Gurdev S. , Stebbins G. Ledyard
Published: January 2018

Khush, G. S., and G. L. Stebbins. (U. California, Davis.) Cytogenetic and evolutionary studies in Secale. I. Some new data on the ancestry of S. cereale. Amer. Jour. Bot. 48(8): 723–730. Illus. 1961.—Cultivated rye, Secale cereale, was crossed with all 4 wild species of the genus. It crosses readily with S. montanum, S. africanum, and S. vavilovii, but crossability of S. cereale and S. silvestre is extremely low. Meiosis in the hybrid S. cereale × silvestre is characterized by high frequency of univalents at metaphase I, reduced chiasma frequency at metaphase I, high frequency of PMC's with unequal separations and laggards at anaphase I and II, high frequency of microspores with micronuclei, and extremely low pollen fertility. These abnormalities occurred less frequently in other hybrids, and consequently the pollen fertility is fairly high: 19.1% in the hybrid S. cereale × vavilovii and 31.3% and 31.8%, respectively, in the hybrids S. cereale × montanum and S. cereale × africanum. An interesting cytogenetic feature of all these hybrids, however, was the formation of a translocation configuration of 6 chromosomes at metaphase I of meiosis. In the hybrid, S. cereale × silvestre, a translocation configuration of 8 chromosomes was observed in a few cells. It is evident, therefore, that the genome of S. cereale differs from the genomes of wild species by 2 translocations. Another small translocation may differentiate S. cereale and S. silvestre, in addition. Thus, on the basis of chromosome arrangements, no particular wild species is most likely to be ancestral to S. cereale. Similarly, Stutz's hypothesis of hybrid origin of S. cereale seems highly improbable. After considering ecological preferences, breeding habits, geographical distribution, morphological and cytological affinities of wild species and cultivated rye, it is concluded that S. cereale evolved from S. montanum as a result of progressive cytological and morphological differentiation and that this differentiation was facilitated, probably, by adaptive superiority of translocation heterozygotes and rearrangement homozygotes.
ALKALINE EARTH ELEMENTS AND ZOOSPORE RELEASE AND DEVELOPMENT IN PROTOSIPHON BOTRYOIDES
Authors: O'Kelley Joseph C. , Herndon Walter R.
Published: January 2018

O'Kelley, Joseph C., and Walter R. Herndon. (U. Alabama, University.) Alkaline earth elements and zoospore release and development in Protosiphon botryoides. Amer. Jour. Bot. 48(9): 796–802. Illus. 1961.—Cells of Protosiphon botryoides Klebs from depleted nutrient medium containing Ca were washed and resuspended in fresh complete medium with Ca; or in media with a Sr, Ba or Na replacement, respectively, for Ca; or in an equivalent CaCl2 solution or deionized water. Zoospore release was observed in these media upon illumination following a 12‐hr dark period. Free zoospores were less abundant in Sr‐, Ba‐ and Na‐replacement media than in the Ca medium. Zoospore production and release also were depressed in solutions of only CaCl2 and in deionized water. In the Sr and Ba media, zoospores were formed but not released from the parent cell, as a rule; some zoospores were released in mass within a gelatinous vesicle which did not liquefy and set the zoospores free; these zoospores lost motility and continued development in Sr, producing characteristic, spheroidal clusters of aplanospores. In the Na medium, protoplasmic cleavage preceding zoospore formation was severely inhibited. A study of the reversibility of Sr inhibition of the zoospore‐release mechanism revealed evidence of reversion 12 hr after replacement of Sr by Ca. Walls of cells produced in Ca are rich in ruthenium red‐positive materials, whereas cells produced under conditions of Sr replacement lack these materials. The significance of these findings in relation to the Ca requirement of other algal species is discussed.
THE EFFECT OF AUXIN AND GUANINE ON CELL EXPANSION AND CELL DIVISION IN THE GAMETOPHYTE OF THE FERN, ONOCLEA SENSIBILIS
Authors: Miller John H.
Published: January 2018

Miller, J. H. (Yale U., New Haven, Conn.) The effect of auxin and guanine on cell expansion and cell division in the gametophyte of the fern, Onoclea sensibilis. Amer. Jour. Bot. 48(9): 816–819. Illus. 1961.—Auxin and guanine promote cell expansion in 0. sensibilis gametophytes. The optimum concentration of auxin for total expansion is 10−‐5 M, but the optimum for elongation is 10−‐6 M. Above this concentration the cells expanded isodiametrically. Guanine is active at higher concentrations than auxin. Increasing concentrations of auxin progressively inhibit red light‐induced cell division, while guanine has no effect on cell division. Neither kinetin nor adenine promotes cell expansion or cell division.
CHROMOSOME NUMBERS IN COMPOSITAE. II. HELENIEAE
Authors: Raven Peter H. , Kyhos Donald W.
Published: January 2018

Raven, Peter H. (Rancho Santa Ana Botanic Garden, Claremont, Calif.), and Donald W. Kyhos. Chromosome numbers in Compositae. II. Heleniae. Amer. Jour. Bot. 48(9): 842–850. Illus. 1961.—Chromosome counts are now available for 42 of the approximately 55 genera of Compositae, tribe Helenieae, which is predominantly a group of western North America. These chromosome numbers are summarized here at the generic level, and 100 original counts for the tribe are added, including what seem to be the first published reports for the genera Amblyopappus, Baeriopsis, Hulsea, Jaumea, Pericome, Rigiopappus, Trichoptilium, and Venegasia, as well as for many species. The phylogeny of Chaenactis is discussed in the light of published records and 46 original counts, and C. douglasii is shown to include plants in which n = 6, 12, and 18, which differ somewhat morphologically. Helenium has species which have a complete series of aneuploid numbers from n = 13 to n = 17. Chromosome numbers coincide with morphological variability in indicating that Helenieae are a diverse group. More detailed studies of various kinds will be necessary before the genera of Helenieae can be re‐aligned effectively, but it is evident that different genera show affinities with various other tribes of the family. Nevertheless, it is thought to be convenient to continue to recognize Helenieae at the tribal level for the present.
OSMOTIC ADJUSTMENT OF PLANTS TO SALINE MEDIA. I. STEADY STATE
Authors: Bernstein Leon
Published: January 2018

Bernstein, Leon. (U. S. Salinity Lab., Riverside, Calif.) Osmotic adjustment of plants to saline media. I. Steady state. Amer. Jour. Bot. 48(10): 909–918. Illus. 1961.—The osmotic pressure (OP) of roots, as well as the OP of aboveground parts of cotton and pepper plants, increase pari passu with increases in the OP of the medium over as wide a range of salinity as would permit any growth. New plasmolytic and cryoscopic techniques yield comparable OP values for roots when dilution of cell sap by the free‐space solution and by endosmosis during rinsing of roots are taken into account. Since OP differentials between plant parts and root media are maintained, turgor does not decrease and growth inhibition by salinity cannot be attributed to water stress in the sense of lowered plant turgor. Some alternative mechanisms for osmotic inhibition of growth are considered and the osmotic adjustment process itself is indicated as a likely limiting factor for growth under saline conditions. Osmotic adjustment of cells to salinity depends in part on increased accumulation of ions and also on substitution of monovalent for polyvalent ions. The relative importance of increased salt accumulation, ionic substitution and increased non‐electrolyte concentration varies with organ (leaf or root), leaf age and salinity level.
AN ANALYSIS OF LEAF ELONGATION IN XANTHIUM PENSYLVANICUM PRESENTED IN RELATIVE ELEMENTAL RATES
Authors: Maksymowych Roman
Published: January 2018

Maksymowych, Roman. (Villanova U., Villanova, Pa.) An analysis of leaf elongation in Xanthium pensylvanicum presented in relative elemental rates. Amer. Jour. Bot. 49(1): 7–13. Illus. 1962.—Xanthium plants were grown vegetatively, and leaves, whose developmental stages were specified by a previously described leaf plastochron index (L.P.I.), were marked with India ink along the midrib and photographed during 3 successive days. The relative elemental rates of elongation, d(dX/dpl)/dX were estimated during the whole course of development. The pattern of elongation was not constant but was changing with increasing plastochron age of the leaf. The elements of a young leaf of L.P.I. 0.75 elongated with a constant relative rate. In older leaves, the d(dX/dpl)/dX values were progressively declining toward the tip of the lamina. After L.P.I. 6.3 the only increment in length was due to the elongation of the elements of the petiole. The pattern of growth distribution is discussed in terms of relative elemental rates with respect to cell division and cell elongation in various portions of the lamina and is correlated with the basipetal trend of tissue differentiation in the developing Xanthium leaf.
CYTOTAXONOMIC STUDIES IN THE EUPHORBIACEAE, SUBTRIBE PHYLLANTHINAE
Authors: Webster Grady L. , Ellis J. R.
Published: January 2018

Webster, Grady L. (Purdue U., Lafayette, Ind.), and J. R. Ellis. Cytotaxonomic studies in the Euphorbiaceae, subtribe Phyllanthinae. Amer. Jour. Bot. 49:(1): 14–18. Illus. 1962.—Chromosome numbers are reported for 18 species of mostly West Indian Euphorbiaceae, subtribe Phyllanthinae, 13 of these for the first time (including the first published count for the genus Margaritaria). For 4 species, a number different from previous determinations has been recorded. The base chromosome number in Breynia, Fluggea, Margaritaria, and most species of Phyllanthus appears to be 13. However, in Phyllanthus subg. Isocladus haploid numbers of 8 and 18 were observed. One species, Phyllanthus pulcher, is a sterile hexaploid (n = 39) of presumably hybrid origin. The cytological data do not support Perry's suggestion that annual taxa are primitive in the Euphorbiaceae.
THE CUP PLASTID OF NICOTIANA RUSTICA
Authors: Weier T. E. , Stocking C. R.
Published: January 2018

Weier, T. E., and C. R. Stocking. (U. California, Davis.) The cup plastid of Nicotiana rustica. Amer. Jour. Bot. 49(1): 24–32. Illus. 1962.—In situ and isolated chloroplasts of Nicotiana rustica have been studied by light and electron microscopy. Under certain conditions, notably of low light intensity, the starch‐free plastid forms a cup. In isolated plastids the form may be modified by the tonicity of the isolation medium. In situ, the cup always faces the cell wall. Electron micrographs show the cup to be formed of compartmented grana connected at irregular intervals by flexuous channels known as frets. The interior of the cup is filled with a finely granular stroma which also forms the material surrounding the grana and the frets in the body of the cup. The grana radiate outward from the central stroma. They may be considered as cylinders. They are fairly rigid, as curvatures to form the cup‐shape occur only in the interconnecting fretwork. The compartments may have a limited movement with reference to their axis. These evidences of movement of the part of the ultramicro plastid structures thought to contain chlorophyll suggest that the movement may be related to changes in light intensity or other factors influencing the rate of photosynthesis.
CHROMOSOME STUDIES IN THE ALPINE AND SUBALPINE FLORAS OF MEXICO AND GUATEMALA
Authors: Beaman J. H. , De Jong D. C. D. , Stoutamire W. P.
Published: January 2018

Beaman, J. H. (Michigan State U., East Lansing), D. C. D. De Jong, and W. P. Stoutamire. Chromosome studies in the alpine and subalpine floras of Mexico and Guatemala. Amer. Jour. Bot. 49(1): 41–50. Illus. 1962.—Chromosome counts of 101 collections representing 69 species in 42 genera and 22 families have been obtained. Counts are reported for the first time in 59 species and 2 genera (Oreobroma and Villadia). Counts establishing new basic numbers were found in Draba, Lithospermum, and possibly in Arenaria. Where pertinent, the chromosomal data are related to previous taxonomic or chromosomal investigations. Chromosome numbers are now known in nearly half of the species in the alpine flora of Mexico.
CYTOPLASMIC STRUCTURE OF HEALTHY AND TMV‐INFECTED LIVING CELLS
Authors: Solberg R. A. , Bald J. G.
Published: January 2018

Solberg, R. A., and J. G. Bald. (U. California, Los Angeles.) Cytoplasmic structure of healthy and TMV‐infected living cells. Amer. Jour. Bot. 49 (2) : 149–157. Illus. 1962.—Epidermal leaf hairs from tobacco‐mosaic‐virus‐infected (TMV) tobacco plants were examined with a high‐resolution, phase‐contrast microscope. The infected cells were at a stage, following virus multiplication, when many of them contained crystals and X‐bodies. Attention was concentrated on the background cytoplasm. Structural features were seen that do not usually appear in descriptions of normal cytoplasm. In the parietal cytoplasm of normal cells are relatively homogeneous regions and regions containing what may be interpreted as included portions of the vacuolar system (vesicles). There are also ridges on the vacuolar surface of the cytoplasm representing lines of flow. Thus, the cytoplasm has a varied and changeable topography. The description of normal cytoplasm, apart from such features, corroborates many observations of previous workers; but some of these are included to provide the necessary contrast with diseased cytoplasm. Cytoplasm infected with TMV exhibits increased density and viscosity. Vesicles become isolated, some of the membranous separations retract, cyclosis slows, and vesicles become less elongate as the forces of cyclosis are reduced. Lines of flow in the nonvesiculate cytoplasm may also retract. Typical virus crystals precipitate. X‐bodies form from regions of coagulated cytoplasm and include constituents of the chondriome. The relationship between the vesiculate nature of cytoplasm and the endoplasmic reticulum of electron microscopists is discussed. The presence of non‐aggregated, dispersed virus in cytoplasm is related to the microscopic symptoms of TMV infection.
A PROBLEMATIC FILAMENTOUS SAPROPHYTIC ALGA
Authors: Singh R. N.
Published: January 2018

Singh, R. N. (Banaras Hindu U., Varanasi 5, India.) A problematic filamentous saprophytic alga. Amer. Jour. Bot. 49 (2) : 188–191. Illus. 1962.—A problematic, filamentous and saprophytic alga, having superficial resemblance to a water‐mold, is described. Although some of its features, such as highly vacuolated colorless protoplast, non‐cellulosic cell wall, and peg‐like outgrowths from the filaments, show fungal affinities, it has been considered to be a saprophytic alga. Its characteristic setiferous branches of large cells, sporangia with recurved sterigmata and, at times, its heterotrichy show affinities with Trentepohlia.
THE RELATIONSHIP BETWEEN THE THICKNESS OF DECIDUOUS LEAVES AND THEIR MAXIMUM PHOTOSYNTHETIC RATE
Authors: McClendon John H.
Published: January 2018

McClendon, John H. (U. Delaware, Newark.) The relationship between the thickness of deciduous leaves and their maximum photosynthetie rate. Amer. Jour. Bot. 49(4): 320–322. Illus. 1962.—Data of Willstätter and Stoll (25°, saturating light and CO2) are used to show that it is useful to plot photosynthetie rate per unit area as a function of the density thickness (g/cm2; fresh wt) of the leaves. Data for 23 species were plotted together. If P is photosynthetie rate, T the total density thickness, E the density thickness of the epidermis, a linear relation is found using the maximum values of P, such that P = R (T ‐ E), where R is about 30 (mg CO2) (hr)‐1 (g F.W.)‐1. Using this expression, 15 species were represented by values of R over 23, while very young leaves, aurea2 leaves and a few others fell in the range 8–16. A mean value of E was taken, from other data, to be about 3 × 10‐3 g/cm2, while T ranged from 10 to 40 × 10‐3 g/cm2, and P ranged from 0.2 to 0.8 (mg CO2) hr‐1 cm‐2 for “normal” leaves.
CLONAL VARIATION OF GRAPE‐STEM AND PHYLLOXERA‐GALL CALLUS GROWING IN VITRO IN DIFFERENT CONCENTRATIONS OF SUGARS
Authors: Arya H. C. , Hildebrandt A. C. , Riker A. J.
Published: January 2018

Arya, H. C., A. C. Hildebrandt, and A. J. Riker. (University of Wisconsin, Madison, Wisconsin.) Clonal variation of grape‐stem and Phylloxera‐gall callus growing in vitro in different concentrations of sugars. Amer. Jour. Bot. 49(4): 368–372. Illus. 1962.—The original callus grown from normal tissue and that grown from gall tissue contained mixtures of different kinds of cells. To study the variability, a large number of clones were developed by single‐cell technique. From these, 6 clones were selected for detailed study. Growth was compared of 6 single‐cell clones established in vitro; 3 from normal grape stem and 3 from gall tissues incited by Phylloxera vastatrix Planch. The clones were stable in growth rate (fast, medium, and slow) when grown on modified White's basal medium supplemented with coconut milk, α‐naphthaleneacetic acid (NAA), and calcium pantothenate. Growth was measured after 6 weeks as the average wet weight on concentrations from 0.06–4.0% of sucrose, d(+) dextrose, d(‐) levulose, d(+) mannose, d(+) galactose, and d(+) lactose, respectively. Every sugar, except mannose, was a suitable source of carbon. The cells were not all alike in their growth response to different sugars. Gall‐ and normal‐tissue clones grew best with 0.125% sucrose, levulose, and galactose. With dextrose and lactose, optimum yields were obtained at the 1.0% sugar level. Growth of fast‐, medium‐, and slow‐growing clones was altered with the type of sugar. Gall and normal tissues were differentiated from each other when grown on mannose in which gall tissues grew best at 0.125% and normal at 1.0% levels. Gall tissues as a group were able to grow better with mannose than the corresponding normal ones. Levulose, on the other hand, favored growth of normal clones in comparison to that of diseased ones. Sugars varied in their inhibitory influence at the 4.0% level. Dextrose, levulose, and lactose at 1.0% proved better than sucrose for the growth of all except one fast‐growing gall clone which grew best with sucrose. However, at 0.125% sugar levels, even in cases where high yields were obtained, the physical character of the tissues changed to dry, brownish, and very friable. Thus, the original callus from normal and gall tissues contained cells with diverse characteristics. The various clones developed used the same sugars but varied strikingly in the rate and type of growth on certain sugars.
GROWTH AND SEXUAL REPRODUCTION OF APHANOMYCES EUTEICHES AS AFFECTED BY THE OXIDATION STATE OF SULFUR
Authors: Davey C. B. , Papavizas G. C.
Published: January 2018

Davey, C. B., and G. C. Papavizas. (Crops Res. Div., ARS, USDA, Beltsville, Md.) Growth and sexual reproduction of Aphanomyces euteiches as affected by the oxidation state of sulfur. Amer. Jour. Bot. 49(4): 400–404. Illus. 1962.—Growth and sexual reproduction of Aphanomyces euteiches Drechs., as affected by the oxidation state of sulfur (S), were studied in synthetic media containing d‐glucose, dl‐glutamic acid, mineral salts phosphate buffer, and various S sources. Organic and inorganic S sources representing some oxidation numbers (valences) were added to the media at concentrations to provide a range from 0 to 128 mg S/liter. The initial reaction in both liquid and solid media was adjusted to pH 6.2. Liquid cultures were maintained at that pH by periodic adjustment. Oxidized S with oxidation number +6 or +4 was not utilized by the fungus, whereas good growth was obtained in the presence of S with oxidation numbers of 0 or ‐2. Although differences existed among isolates as to relative rates of utilization of the various S sources, there was complete conformity among isolates as to which sources were utilized for growth. Some isolates did not utilize all available S sources for sexual reproduction.
ONTOGENY AND COMPARATIVE ANATOMY OF THORNS OF HAWAIIAN LOBELIACEAE
Authors: Carlquist Sherwin
Published: January 2018

Carlquist, Sherwin. (Claremont Graduate School, Claremont, Calif.) Ontogeny and comparative anatomy of thorns of Hawaiian Lobeliaceae. Amer. Jour. Bot. 49(4): 413–419. Illus. 1962.—Species of Rollandia and Cyanea (sections Genuinae and Palmaeformes), endemic Hawaiian genera of Lobeliaceae, are unique in the family in possessing thorns and thorn‐like structures on leaves, and in some cases, on stems and flowers. These thorns always originate in conjunction with a unicellular, non‐glandular trichome which terminates the thorn. Ontogenetic studies show that divisions leading to the formation of the thorn occur in the ground meristem as soon as the trichome is differentiated. Periclinal divisions predominate at first, but anticlinal and diagonal ones are also present at all stages. Thick secondary walls are formed on the trichome and other epidermal cells near the thorn tip. Periderm forms on old thorns of stems. Vascular tissue and laticifers are absent in thorns. Thorns in Cyanea and Rollandia seem best interpreted as specializations within these genera.
ONTOGENY OF THE CLOSED DICHOTOMOUS VENATION OF REGNELLIDIUM
Authors: Pray Thomas R.
Published: January 2018

Pray, Thomas R. (U. South. California, Los Angeles.) Ontogeny of the closed dichotomous venation of Regnellidium. Amer. Jour. Bot. 49(5): 464–472. Illus. 1962.—The venation of the pinna of Regnellidium consists of a flabellate series of dichotomizing vascular strands, branches of a single pinna trace. At the laminal margin, the entire venation is closed by a marginal vein. The development of the pinna was investigated primarily by means of paradermal sections. During early development, the organization of the marginal meristem and its derivatives is very similar to that previously described for Nephrolepis. The arrangement of cells in the embryonic pinna is predisposed for the differentiation of dichotomizing procambial strands. During the final phases of pinna development, the marginal meristem is altered in such a manner as to result in a submarginal band of elongated cells which differentiates a marginal procambial strand connecting the tips of the dichotomizing veins. Relatively late in pinna ontogeny and after the entire procambial venation pattern has been delimited, the marginal meristem becomes inactive. The possible correlation between extended marginal growth and dichotomizing veins is discussed.
LYCOPODIUM PROTHALLI AND THEIR ENDOPHYTIC FUNGI AS STUDIED IN VITRO
Authors: Freeberg J. A.
Published: January 2018

Freeberg, John A. (Lehigh U., Bethlehem, Pa.) Lycopodium prothalli and their endophytic fungi as studied in vitro. Amer. Jour. Bot. 49(5): 530–535. Illus. 1962.—A fungus isolated from a prothallus of Lycopodium obscurum is described. This fungus was found to invade prothalli of L. complanatum, L. selago and L. cernuum. The association of the fungus with L. complanatum in vitro is such that the form of the prothallus as well as the general area of fungus invasion approaches that of prothalli in nature. Prothalli grown with the fungus on a starch medium were found to gain in weight more rapidly than prothalli grown alone. This suggests that the presumed symbiotic relationship in nature can be duplicated in vitro under certain conditions.
DISTRIBUTION OF TERRESTRIAL ALGAE WITHIN THE NEVADA TEST SITE
Authors: Shields Lora Mangum , Drouet Francis
Published: January 2018

Shields, Lora Mangum, and Francis Drouet. (New Mexico Highlands U., Las Vegas.) Distribution of terrestrial algae within the Nevada Test Site. Amer. Jour. Bot. 49(6): 547–554. Illus. 1962.—Twelve terrestrial algal species, other than diatoms, were identified by microscopic examination of natural soil growths from the Nevada Test Site. Four soil species appeared in culture only. Fifteen taxa occurred only in the vicinity of the one aquatic habitat. Colloidal sheaths of Microcoleus vaginatus, Schizothrix californica and Schizothrix aculissima stabilize soil particles, forming a surface crust. Nostoc commune, Scytonema hofmannii and Protosiphon cinnamomeus are commonly associated with lichens. With one exception, no natural algal growths were found within 0.6 mile of nuclear detonation points during the 2 years following an event. Since at least one species, Microcoleus vaginatus, survives acute gamma exposures of 2,560 kr, blast and thermal damage, rather than radiation, appear to account for the removal of soil algae. The slow recovery can be explained largely in terms of aridity. Soil texture, which influences cohesiveness and moisture levels, strongly affects the composition of terrestrial algal populations in relation to major shrub types within the test site.
TERMINAL PHLOEM IN VASCULAR BUNDLES OF LEAVES OF CAPSICUM ANNUUM AND PHASEOLUS VULGARIS
Authors: de Morretes Berta Lange
Published: January 2018

Morretes, Berta Lange de. (U. Sao Paulo, Brazil.) Terminal phloem in vascular bundles of leaves of Capsicum annuum and Phaseolus vulgaris. Amer. Jour. Bot. 49(6): 560–567. Illus. 1962.—The terminations of vascular bundles in the mesophyll of Capsicum annuum and Phaseolus vulgaris were studied in mature leaves. In Capsicum, both the principal and the lateral vein endings contain phloem and, generally, the xylem and the phloem end together; in some bundles, however, the last xylem element extends slightly beyond the last sieve element. In Phaseolus, main and lateral vein endings may terminate with both xylem and phloem, or xylem only. Some lateral endings contain no sieve elements; in such endings, parenchyma may occupy the position of the phloem. The sieve elements of the vein endings contain slime bodies. In both species the companion cells of terminal phloem are wider than the sieve elements, have dense cytoplasm, and rich granulation.
A REVISION OF ARIOCARPUS (CACTACEAE). II. THE STATUS OF THE PROPOSED GENUS NEOGOMESIA
Authors: Anderson Edward F.
Published: January 2018

Anderson, Edward F. (Pomona Coll., Claremont, California.) A revision of Ariocarpus (Cactaceae). II. The status of the proposed genus Neogomesia. Amer. Jour. Bot. 49(6): 615–622. Illus. 1962.—The proposed monotypic genus Neogomesia is found to be similar to Ariocarpus in seed structure, seedling development, habitat, certain significant internal characters, chemistry, flowers, pollen, and chromosomes. The reported differences in a reole structure and fruits are unfounded, if the developmental stages of each are considered. The presence of extensive mucilage‐containing structures in Neogomesia is significant, because these structures have been reported previously only in Ariocarpus. Interspecific compatibility shows close genetic similarities between Neogomesia agavoides and the several species of Ariocarpus. The difference in structure of mature tubercles between Neogomesia and Ariocarpus is believed to be a variation in the location of growth and elongation with respect to the floriferous and spiniferous areolar areas. The author concludes that Neogomesia agavoides Castañeda should be placed in the genus Ariocarpus.
DISTRIBUTIONS OF GROWTH, NUCLEIC ACIDS, AND NUCLEIC‐ACID SYNTHESIS IN SEEDLING ROOTS OF ZEA MAYS
Authors: Woodstock Lowell W. , Skoog Folke
Published: January 2018

Woodstock, Lowell W., and Folke Skoog. (U. Wisconsin, Madison.) Distributions of growth, nucleic acids, and nucleic‐acid synthesis in seedling roots of Zea mays. Amer. Jour. Bot. 49(6): 623–633. Illus. 1962.—The rate of growth of each of 6 inbred lines of Zea mays was shown earlier to be directly proportional to the amount of ribonucleic acid (RNA) in the apex. In the present communication, 2 of these lines, W–58 and W–148, have been studied with respect to the distribution of growth and RNA in a further attempt to elucidate the relationship between cell elongation and RNA. Two‐day‐old W–58 roots grew 1.01 mm/hr, had a growing region of 9.0 mm, and a maximum relative elemental rate of elongation of 0.23 mm/hr/mm. Two‐day‐old W–148 roots grew 1.56 mm/hr, had a growing region of 11.0 mm, and a maximum relative elemental rate of elongation of 0.26 mm/hr/mm. In W–58, rapid RNA synthesis occurred over the apical 2.0 mm and the maximum level was 1.40 × 10‐4μg RNA/cell. In W–148, rapid RNA synthesis occurred over the first 4.0 mm to give a maximum level of 2.34 × 10‐4μg RNA/cell. Fresh weights per cell increased to 122 × 10‐6 mg in W–58 and to 160–190 × 10‐6 mg in W–148. The estimated duration of rapid cell elongation of an individual cell was 13.9 hr in W–58 and 13.4 hr in W–148. The results are in agreement with the hypothesis that the amount of RNA synthesis by the cells while still in the apex determines their subsequent rate of elongation as well as their final size.