bluuebunny/crossref_metadata_2025 huggingface dataset:
THE DEVELOPMENT OF THE SEED OF ABUTILON THEOPHRASTI. II. SEED COAT
Authors: Winter Dorothy M.
Published: January 2018

Winter, Dorothy M. (Iowa State U., Ames.) The development of the seed of Abutilon theophrasti. II. Seat coat. Amer. Jour. Bot. 47(3) : 157—162. Illus. 1960.–The integuments of Abutilon theophrasti Medic. undergo a rapid increase in size, predominantly by anticlinal cell divisions during the first 3 days after fertilization. Within 7 days, the outer epidermis of the inner integument becomes thick walled. At maturity this compact, lignified, and cutinized palisade layer accounts for more than half the thickness of the seed coat. During early growth, the palisade cells form a continuous layer in the micropylar region. In the chalazal region the palisade layer is discontinuous in a slit‐shaped region, 60 × 740 microns. The shape of this discontinuity constitutes a major difference between dormant‐seeded Abutilon and non‐dormant Gossypium seeds. Exterior to the palisade layer is the outer integument which consists of a small‐celled layer and a large‐celled layer sparsely covered with unicellular, lignified hairs. Interior to the palisade is the thick mesophyll of the inner integument which is largely digested during seed growth and leaves only 2 pigmented cell layers in most regions at maturity. The inner epidermis is small‐celled, pigmented and cutinized and adheres tightly to the endosperm. Seed coat impermeability increases with seed maturity. Even immature seeds will germinate, if scarified, indicating a lack of embryo dormancy.
THE DEVELOPMENT OF THE SEED IN ANDROGRAPHIS SERPYLLIFOLIA
Authors: Ram H. Y. Mohan
Published: January 2018

Mohan Ram, H. Y. (U. Delhi, India.) The development of the seed in Andrographis serpyllifolia. Amer. Jour. Bot. 47(3) : 215—219. Illus. 1960.–Andrographis serpyllifolia, a member of the Acanthaceae, has an embryo sac with a bifurcated chalazal part. At the time of fertilization both synergids and antipodal cells disintegrate. Early in its development the endosperm is composed of 3 distinct parts: (1) a binucleate densely cytoplasmic chalazal haustorium; (2) a large binucleate micropylar haustorium; and (3) a central chamber which develops into the endosperm proper. The divisions in the central endosperm chamber are ab initio cellular. A few of the endosperm cells elongate enormously, ramify into the integument and destroy the surrounding cells. These cells have been termed secondary haustoria. Due to the unequal destruction of the integument, the endosperm assumes a ruminate condition. The mature seed is nearly naked because the seed coat is almost completely digested. The embryo has a long suspensor. The micropylar cells of the suspensor are hypertrophied and multinucleate. Contrary to Mauritzon's (1934) belief, the course of endosperm development is markedly different from that observed in Thunbergia. So far, albuminous seeds have been reported only in the subfamily Nelsonioideae. The present investigation provides a case of its occurrence in the Acanthoideae also.
APOMIXIS AND POLYEMBRYONY IN PACHIRA OLEAGINEA (BOMBACACEAE)
Authors: Baker H. G.
Published: January 2018

Baker, H. G. (U. California, Berkeley.) Apomixis and polyembryony in Pachira oleaginea (Bombacaceae). Amer. Jour. Bot. 47(4): 296—302. Illus. 1960.–Trees identified as Pachira oleaginea Decne. are now widely cultivated in tropical and subtropical Africa. Specimens from Achimota, Ghana, are shown to contain 1—5 embryos in a single seed. The flowers, which open at night, are self‐compatible but need to be pollinated for seed‐setting to occur. Maturation of the fruit takes about 2 mo. but the seeds germinate soon after shedding. One embryo in each seed is usually much the largest and the only one to become established as a seedling. There is no relation between seed‐size and numbers of embryos contained. Histological and cytogical studies show that adventitious embryony is responsible for the excess embryos following the formation of a normal sexually produced embryo (2n=72) and endosperm (3n=108). Adventitious embryos arise from single cells in the nucellus in the vicinity of the micropyle and appear to develop faster than the sexually produced embryo with consequent frequent apomictic reproduction. This is the first report of apomixis in the Malvales, which may have important practical consequences as P. oleaginea is a potential economic plant and may fruit only 3 yr. after sowing, rendering seed‐propagation feasible.
CHROMOSOMAL RELATIONSHIPS AND TAXONOMIC CONSIDERATIONS IN THE GENUS CASSIA
Authors: Irwin H. S. , Turner B. L.
Published: January 2018

Irwin, H. S. and B. L. Turner. (U. Texas, Austin.) Chromosomal relationships and taxonomic considerations in the genus Cassia. Amer. Jour. Bot. 47(4): 309‐318. 1960.—All chromosome numbers known for the genus Cassia are arranged in a table which follows the infrageneric organization of Bentham (1871). Included are new counts for 88 taxa, of which 68 are first reports. Evidence is represented which suggests that the base number for the genus is 7, the other numbers having been derived by aneuploid loss from various euploid levels. The basic number 8, of general occurrence in the Subsection Leiocalyx, Section Chameacrista, is presumed to have been derived from the ancestral generic base by aneuploid gain of 1 chromosome. The results of the present study do not support elevation of the section Chamaecrista to generic rank. In general, the basic soundness of Bentham's revision is upheld.
ONTOGENY OF THE OPEN DICHOTOMOUS VENATION IN THE PINNA OF THE FERN NEPHROLEPIS
Authors: Pray Thomas R.
Published: January 2018

Pray, Thomas r. (U. South. California, Los Angeles.) Ontogeny of the open dichotomous venation in the pinna of the fern Nephrolepis. Amer. Jour. Bot. 47(5) : 319—328. Illus. 1960.–The venation of the pinna of Nephrolepis consists of a midvein and 2 lateral series of dichotomizing veins all of which terminate freely near the margins. The development of the pinna is analyzed with particular attention to the nature of the marginal meristem and the organization of the embryonic pinna as it appears in paradermal section. The arrangement of cells in pinna wings during the period of marginal growth displays a pattern which foreshadows the pattern of the mature venation. In contrast with the development of the leaves of angiosperms, marginal growth continues into a relatively late phase of pinna ontogeny and apparently is active throughout the phases of ontogeny concerned with blocking‐out the pathways of procambial differentiation. Thus the pattern of venation appears to be correlated with the manner of activity of the marginal meristem and subsequent orientation of its derivatives. The theoretical aspects of the result of this investigation are discussed in relation to other studies of foliar venation ontogeny.
THE INTRACELLULAR MEMBRANES OF BLASTOMYCES DERMATITIDIS
Authors: Edwards George A. , Edwards Mercedes R.
Published: January 2018

Edwards, George A., and Mercedes R. Edwards. (Div. Labs, and Research, N.Y.S. Dept. of Health, Albany.) The intracellular membranes of Blastomyces dermatitidis. Amer. Jour. Bot. 47 (8): 622–632. Illus. 1960.—The yeast cells of Blastomyces dermatitidis have been studied in thin sections with the electron microscope. The cell is multinucleate, and the nuclei are frequently interconnected by their outer limiting membranes. The cell is bordered by a cell wall and the plasma membrane, which may be seen in direct continuity with the nuclear envelope. The cytoplasm contains numerous mitochondria, many profiles of the endoplasmic reticulum, and few multivesicular bodies. The membranes of all the constant cellular components are interconnected. Mitochondria appear to be formed from any of several membrane systems. The micromorphology of the cell suggests efficiency of communication and cytoplasmic mobility.
INFLUENCE OF UPWARD WATER TRANSLOCATION ON UPTAKE OF IONS IN CORN PLANTS
Authors: Smith Richard C.
Published: January 2018

Smith, Richard C. (Rutgers U., New Brunswick, N. J.) Influence of upward water trans location on uptake of ions in corn plants. Amer. Jour. Bot. 47 (9): 724–729. Illus. 1960.—Experiments were performed in which segments of corn roots were surrounded by a nutrient solution which contained radioactive phosphorus, while a second nutrient solution containing no phosphorus was caused to flow upward through the xylem. Results indicate that phosphorus moves radially across the root into the xylem in the absence of any radial water movement, but that increased rate of water movement upward through the xylem increases the rate of radial or inward movement of ions. Results of experiments in which root segments were treated with sodium azide suggest that the movement of phosphorus across the root is independent of, and in competition with, the process of phosphorus accumulation by the cells of the cortex.
THE SPECIES OF CIBORINIA PATHOGENIC TO SALIX, MAGNOLIA, AND QUERCUS
Authors: Batra Lekh R.
Published: January 2018

Batra, Lekh R. (Swarthmore Coll., Swarthmore, Pennsylvania.) The species of Ciborinia pathogenic to Salix, Magnolia, and Quercus. Amer. Jour. Bot. 47(10): 819–827. Illus. 1960.—There are 2 species of Ciborinia that attack various species of Salix. One of these, C. wisconsinensis, is reported as new and its phytopathology and life history are discussed. This species forms sclerotia in the leaves along the midrib. The sclerotia germinate in the year following infection and form apothecia in late June. In culture, sclerotia formed from mass ascospore‐shootings produce apothecia. Ciborinia candolleana is reported for the first time attacking Quercus spp. in the United States. A key to the known species of the genus Ciborinia is provided.
ENVIRONMENTAL CONTROL OF REPRODUCTIVE DEVELOPMENT IN HORDEUM BULBOSUM, A PERENNIAL PASTURE GRASS
Authors: Koller D. , Highkin H. R.
Published: January 2018

Koller, D. (Hebrew U., Jerusalem, Israel), and H. R. Highkin. Environmental control of reproductive development in Hordeum bulbosum, a perennial pasture grass. Amer. Jour. Bot. 47(10): 843–847. Illus. 1960.—The interaction between growth temperature, daylength and vernalization in the control of reproductive development of Hordeum bulbosum was investigated under controlled conditions. The plants are completely vernalizable. Initiation of flowering in unvernalized plants was under strict photoperiodic control at warm growth temperatures and independent of it at cooler ones. Plants in which flowering had been induced, by whatever means, behaved as strict requirers of long days, as far as completion of heading was concerned. The possibility that induction of flowering by vernalization and by photoperiod operate along the same pathway is discussed.
INCOMPATIBILITY IN ABUTILON ‘HYBRIDUM’
Authors: Pandey K. K.
Published: January 2018

Pandey, K. K. (John Innes Hort. Inst., Bayfordbury, Hertford, Herts, England.) Incompatibility in Abutilon ‘Hybridum.’ Amer. Jour. Bot. 47(10): 877–883. Illus. 1960.—Abutilon ‘Hybridum’ (2n = 16) has a one‐locus multiallelic gametophytic (Nicotiana‐type) system of self‐incompatibility. Five S alleles were distinguished among the 4 plants studied. However, the incompatibility behavior in many crosses is obscured by the modifying effects of a number of other genes non‐allelic to the S locus. Since A. ‘Hybridum’ is a cultivar which has arisen through hybridization of 2 or more Abutilon species, it is suggested that the mixed polygenic background of the “species” is not adjusted to the proper functioning of the S gene system. Although most of the plants in the 6 groups studied were highly self‐incompatible in the early and mid season, many of them showed pseudo‐self‐compatibility late in the season. Seed‐set in illegitimate crosses also increased late in the season. Colchicine‐induced autopolyploidy brought about part or full self‐compatibility. After incompatible pollination, pollen germination appeared to be normal but a considerable proportion of the tubes were inhibited in the stigmatic region of the style; tubes which penetrated the style usually burst between ⅕ and ⅓ of the distance from the stigma to the base, a phenomenon not found in any of the other gametophytic‐type species yet studied.
EFFECTS OF GIBBERELLIC ACID ON STEM APICES OF VERNALIZABLE GRASSES
Authors: Roller D. , Highkin H. R. , Caso O. H.
Published: January 2018

Koller, D. (Hebrew U., Jerusalem, Israel), H. R. Highkin, and O. H. Caso. Effects of gibberellic acid on stem apices of vernalizable grasses. Amer. Jour. Bot. 47(6) : 518–524. Illus. 1960.—Gibberellic acid was found to have distinct morphogenic effects on the stem apices of 3 vernalizable but unvernalized grasses: Hordeum vulgare var. ‘Kentucky,’ Hordeum bulbosum and Secale cereale var. ‘Winter Petkus.’ In these 3 species, GA caused the activation of lateral meristems on the embryonic nodes of the stem apices, under both short‐ and long‐day conditions. These lateral meristems differentiated into either flower primordia or vegetative shoots. The flower primordia developed almost invariably in Hordeum, while in Secale they seldom did, the apical meristem usually resuming normal vegetative growth after treatment. Despite the occurrence of flowering, it is concluded that the role of GA in this phenomenon is restricted to the activation of lateral meristems in the apex.
(2 CHLOROETHYL) TRIMETHYLAMMONIUM CHLORIDE AND RELATED COMPOUNDS AS PLANT GROWTH SUBSTANCES. III. EFFECT ON GROWTH AND FLOWERING OF THE TOMATO
Authors: Wittwer S. H. , Tolbert N. E.
Published: January 2018

Wittwer, S. H., and N. E. Tolbert. (Michigan State Univ., E. Lansing.) (2‐Chloroethyl) trimethylammonium chloride and related compounds as plant growth substances. III. Effect on growth and flowering of the tomato. Amer. Jour. Bot. 47(7) : 560–565. Illus. 1960.—Application of 10–3 to 10–7 M solutions of (2‐chloroethyl) trimethylammonium chloride, (2 bromoethyl)‐trimethylammonium bromide, or (2,3‐n‐propylene) trimethylammonium bromide to the roots of the tomato plant markedly altered growth and promoted earlier flowering. Treated plants developed thicker stems, and dark‐green, savoyed leaves. The growth changes were similar to those produced by exposure to high light intensities and low temperatures, and were opposite to, and more persistent than, those induced by gibberellin. A stepwise regulation in the magnitude of growth and dry matter accumulation in tomato plants followed application of chemicals of increasing concentration to cultural solutions. This growth response varied from a stimulation at 10–7 M to a marked suppression at 10–4 M without delay of flowering or visible injury. The control of growth and flowering by the use of these chemicals offers several practical possibilities for their utilization in tomato culture.
THE OCCURRENCE OF TRICHOSCLEREIDS IN THE MONSTEROIDEAE (ARACEAE)
Authors: Nicolson Dan H.
Published: January 2018

Nicolson,DanH. (Cornell U., Ithaca, N. Y.)The occurrence of trichosclereids in the Monsteroideae (Araceae).Amer. Jour. Bot. 47(7): 598–602. Illus. 1960.—A study was made on the presence, distribution, and frequency of trichosclereids within the leaf‐blade, petiole, and stem of 32 species of Monsteroideae and I species of Pothoideae. Trichosclereids occurred in all species studied. Distribution and frequencies of trichosclereids were variable. Trichosclereids occurred more consistently in the petiole than in the leaf‐blade or stem tissues. A new report of trichosclereids outside of the Monsteroideae, inPothos repens(Lour.) Druce of the Pothoideae, is made. The tribe Spathiphylleae(SpathiphyllumandHolochlamys)was found to be characterized in part by large numbers of trichosclereids occurring in groups within the leaf‐blade.
AN EXPERIMENTAL STUDY OF VARIATION IN THE PHACELIA SERICEA COMPLEX
Authors: Gillett George W.
Published: January 2018

Gillett, Georce W. (Michigan State U., East Lansing.) An experimental study of variation in the Phacelia sericea complex. Amer. Jour. Bot. 48(1): 1–7. Illus. 1961.—The Phacelia sericea complex consists of 2 diploid (n = 11), intergrading species, P. idahoensis and P. sericea. The experimental culture of several races of this complex demonstrated that differences in pubescence, leaf shape, and flower shape persist in plants grown in a common environment. Experimental interspecific F1 hybrids demonstrated high fertility; portrayed intermediate expressions of pubescence, leaf shape, and flower shape; and were found to be, in many cases, indistinguishable from many wild intermediates. A study of herbarium specimens revealed numerous intergrades in which pubescence, leaf shape, and flower shape are highly variable, though loosely correlated. The evidence obtained from herbarium specimens, greenhouse cultures, field investigations, chromosome studies, and experimental hybridizations suggests a hybrid origin for the wild intermediates, recognized as Phacelia sericea (Graham) A. Gray subsp. ciliosa (Rydb.) Gillett.
SEMISTERILITY IN THE INTERSPECIFIC HYBRID MELILOTUS POLONICA × M. ALBA
Authors: Jaranowski Julian K.
Published: January 2018

Jaranowski, J. K. (Coll. of Agriculture, ul. Wojska Polskiego 71c, Poznan, Poland.) Semisterility in the interspecific hybrid Melilotus polonica × M. alba. Amer. Jour. Bot. 48(1): 28–35. Illus. 1961.—Interspecific hybrids between Melilotus polonica (n = 8) and M. alba (n = 8) are readily secured. The F1 hybrids are intermediate between the parents and partially sterile with a mean percentage of 58.8 (ranging from 46.8 to 72.6) defective pollen grains. Six bivalents and a chain or ring of 4 chromosomes occur at diakinesis and metaphase‐I of microsporogenesis. A crossshaped configuration characteristic of a reciprocal translocation is present at pachytene, indicating that one of the parents is homozygous for an interchange of relatively large section between two of the members of the chromosome complex. Chromosome bridges, lagging chromosomes, movement of the univalents to the same pole and precocious division of the univalents lead to aberrant chromosome distribution during the course of meiosis. Reduction in self‐fertility indicates a corresponding aberrant distribution of chromosomes during megasporogenesis. Pollen sterility in the F2 generation ranged from 24.8% to 72.5% with a mean value of 54.6%. Two plants in the F2 generation which had relatively low pollen sterility proved to be aneuploids (2n + 1). Meiotic irregularities in the F2 plants were comparable to those exhibited by the F1 plants.
PHYLLOTAXIS AND VASCULAR ORGANIZATION OF THE CARPELS IN MICHELIA FUSCATA
Authors: Tucker Shirley C.
Published: January 2018

Tucker, Shirley C. (U. Minnesota, Minneapolis.) Phyllotaxis and vascular organization of the carpels in Michelia fuscata. Amer. Jour. Bot. 48(1): 60–71. Illus. 1961.—Phyllotaxis pattern and vascular organization are closely related in the floral receptacle of Michelia fuscata (Magnoliaceae). The carpels arise in a spiral or helix. They are initiated alternately along each of 7, 8 or 10 helical parastichies according to a complex repetitive sequence. The pattern of the dorsal carpellary trace fusions is orderly for each of the 10 flowers investigated. The dorsal carpellary traces in each parastichy diverge from the same vascular sympodium. Among flowers one finds differing numbers of parastichies, differing angles of divergence, and varying sequences of parastichies which reflect the order of carpel initiation. The angle of divergence, although consistent for any 1 parastichy in a flower, can vary greatly between parastichies. The nature and importance of the organizers which determine appendage position at the apical meristem are considered. Changes in apical size, configuration, and activity are shown to be related to phyllotaxis.
EMBRYOGENY AND HISTOGENESIS IN NERIUM OLEANDER II. ORIGIN AND DEVELOPMENT OF THE NON‐ARTICULATED LATICIFER
Authors: Mahlberg Paul G.
Published: January 2018

Mahlberg, P. G. (U. Pittsburgh, Pittsburgh, Pa.) Embryogeny and histogenesis in Nerium oleander. II. Origin and development of the non‐articulated Iaticifer. Amer. Jour. Bot. 48(1): 90–99. Illus. 1961.—Laticifer initials, collectively considered as a laticifer system, are differentiated in the globular embryo from meristematic cells which occupy a position within the potential procambial tissue. A total of usually 28 initials, in Nerium oleander, arise as an irregular ring of cells directly below the embryonic shoot apex, during initiation of the cotyledonary primordia. No anastomoses occur between laticifer initials. During subsequent development of the embryo, the laticifer initials grow in a bi‐directional manner and penetrate into the root, cotyledons and toward the shoot apex. Upon enlargement the initials bifurcate repeatedly, many branches penetrate into the cotyledons, others grow into the cortex of the hypocotyl or penetrate between cells of the procambium. Repeated nuclear divisions within each initial result in the formation of a multinucleated protoplast in this cell type. The tips of laticifers occupy intercellular spaces during their growth; they do not penetrate into or through adjacent cells. A plexus of laticifer branches is formed within the cotyledonary node of the mature embryo. No new initials are formed during subsequent growth of the plant, rather certain branches from the cotyledonary nodal plexus penetrate into the enlarging shoot system. The nature of their growth habit and branching suggests that the tips of laticifer initials exhibit an intrusive form of growth.
THE CHROMOSOMES OF THE SEMPERVIVOIDEAE (CRASSULACEAE)
Authors: Uhl Charles H.
Published: January 2018

Uhl, Charles H. (Cornell U., Ithaca, New York.) Chromosomes of the Sempervivoideae (Crassulaceae). Amer. Jour. Bot. 48(2): 114–123. Illus. 1961.—Chromosome numbers are reported for 207 collections representing 68 of the ca. 95 species in this subfamily. Basic numbers are 16, 17, 18, and 19 in Sempervivum, Section Sempervivum (10 species, with many tetraploids and one hexaploid); 19 in Sempervivum, Section Jovisbarba (5 species, all diploid); 15 in Aichryson (9 species, including 1 aneuploid, 1 tetraploid, and 1 aneutetraploid); and strictly 18 in Aeonium (31 species, including 4 wholly and 1 partly tetraploid), Greenovia (3 species, 1 partly tetraploid), and Monanthes (10 species, including 2 wholly and 1 partly tetraploid). The cytological evidence appears decisive in ranking several species of disputed generic position definitely with Aichryson rather than with Aeonium. Possible relationships between various Canarian genera and certain North African species often classed in Sedum are discussed briefly in the light of the scanty morphological and cytological evidence. It is suggested that both these groups may be descended from the same ancestors that were widespread in North Africa before the deserts developed.
A NEW, HETEROTHALLIC SPECIES OF SORDARIA
Authors: Olive Lindsay S. , Fantini A. A.
Published: January 2018

Olive, L. S., and A. A. Fantini. (Columbia U., New York, N. Y.) A new, heterothallic species of Sordaria. Amer. Jour. Bot. 48(2): 124–128. Illus. 1961.—S. brevicollis, sp. nov., was isolated from zebra dung from the New York Zoological Park. It is the only species of the genus that has been found to be heterothallic and to have microconidia. The latter function readily in fertilization. Heterothallism is controlled by a single allelic pair of compatibility factors located about 14.2 crossover units from the centromere. Incomplete mating reactions involving this species, Gelasinospora autosteira, and Neurospora crassa indicate relationships among these 3 genera.
A SEASONAL STUDY OF THE VEGETATIVE SHOOT APEX AND THE PATTERN OF PITH DEVELOPMENT IN HIBISCUS SYRIACUS
Authors: Tolbert Robert J.
Published: January 2018

Tolbert, Robert J. (West Virginia U., Morgantown.) A seasonal study of the vegetative shoot apex and the pattern of pith development in Hibiscus syriacus. Amer. Jour. Bot. 48(3): 249–255. Illus. 1961.—The shoot apex of Hibiscus syriacus L. is described as having a cytohistological zonation superimposed on a tunica‐corpus configuration. The apex is flat‐topped or may have a saddle‐back or concave appearance as seen in median longitudinal section. The metrameristem, consisting of the tunica and corpus initials, is comprised of large, light‐staining, vacuolate cells that have thick cell walls and exhibit much dark‐staining intercellular substance. Surrounding the metrameristem is the flanking meristem, which is responsible for the outer layers of the shoot, and from which the leaf primordia arise. The pith rib meristem lies below the metrameristem and consists of files of cells that are responsible for the pith. There are no major seasonal changes in the structure of the apex during the yearly cycle. The pith displays a long‐shoot type of development with the cells remaining in distinct files during the first flush of growth in the spring. As growth slows and internode elongation is gradually reduced, the pith displays the characteristic short‐shoot type of development, consisting of a spongy tissue of rounded cells with many intercellular spaces and no distinct files of cells. A crown is differentiated across the top of the pith at the end of the growth period. This consists of a band of cells with thick, dark‐staining cell walls, which separates by the apex from the last year's growth. In contrast to many gymnosperms, this crown is dispersed by renewed cell activity the following spring.
REVERSION AND REINDUCTION OF FLOWERING IN PERILLA
Authors: Lam S. L. , Leopold A. C.
Published: January 2018

Lam, S. L., and A. C. Leopold. (Purdue U., Lafayette, Indiana.) Reversion and reinduction of flowering in Perilla. Amer. Jour. Bot. 48(4): 306–310. Illus. 1961.—Plants of Perilla crispa (Thunb.) Tanaka ultimately revert to the vegetative state provided that they have received not more than about 20 cycles of short photoperiods. Reversion is markedly promoted by repeated debudding of plants induced with 35 cycles or less. Reverted plants of Perilla could be reinduced twice by photoperiodic treatment of the originally induced leaves. Timing experiments to measure the flow of flower stimulus from induced leaves suggest a gradual loss of the stimulus, as indicated by increased time to appearance of flowers and decreased flower number. It is concluded that after the inductive treatment is withdrawn, the effectiveness of the flower stimulus coming from the leaf declines with time. It is suggested that reversion is made possible by the decline of effective flower stimulus coming from the induced leaves.
METABOLIC STUDIES OF GAMMA‐IRRADIATED WHEAT GROWING WITHOUT CELL DIVISION
Authors: Haber Alan H. , Carrier William L. , Foard Donald E.
Published: January 2018

Haber, Alan H., William L. Carrier, and Donald E. Foard. (Biol. Div., Oak Ridge Natl. Lab.,3 Oak Ridge, Tenn.) Metabolic studies of gamma‐irradiated wheat growing without cell division. Amer. Jour. Bot. 48(6): 431–438. Illus. 1961.—Wheat grains given 800 kr of Co60 gamma radiation before moistening can germinate and grow into small seedlings without cell division or desoxyribonucleic acid (DNA) synthesis. This growth is sustained by metabolism and is not merely water uptake. The growing seedlings increase in dry matter, protein, and ribonucleic acid (RNA). They can perform photosynthesis by fixing carbon from CO2 into sugar phosphates, sucrose, amino acids, and organic acids. These results suggest that such irradiated cereals may be used for certain physiological and anatomical studies of germination and development in an intact growing organism in the absence of DNA synthesis, mitosis, and cell division.
CYTOGEOGRAPHY AND PHYLOGENY OF THE NORTH AMERICAN SPECIES OF VERBENA
Authors: Lewis Walter H. , Oliver Royce L.
Published: January 2018

Lewis, Walter H., and Royce L. Oliver. (Stephen F. Austin State Coll., Nacogdoches, Texas.) Cytogeography and phylogeny of the North American species of Verbena. Amer. Jour. Bot. 48(7): 638–643. Illus. 1961.—Chromosome numbers of 26 Verbena species in North America, separable into 2 series, are reported. The x = 5 series has no diploid representative, few tetraploids, and numerous widespread hexaploid species, while the x = 7 series has many pandemic diploid species and few tetraploid and hexaploid taxa. When compared with the data available for the South American verbenas, these frequencies and distributions were found to be almost opposite. The origin of the 2 groups from an x = 6 prototype followed by ascending and descending aneuploidy is suggested. Migration via tropical land bridges is proposed to explain the occurrence of both groups in the 2 continents. The following taxa are proposed: subgenus Verbenaca (Schauer) Lewis, and subgenus Glandularia (Gmelin) Lewis.
THE CHANGING CONCEPT OF AUXIN
Authors: Kefford N. P. , Goldacre P. L.
Published: January 2018

Kefford, N. P., and P. L. Goldacre. (Division of Plant Industry, C.S.I.R.O., Canberra, Australia.) The changing concept of auxin. Amer. Jour. Bot. 48(7): 643–650. Illus. 1961.—Recent findings in auxin research are interpreted as follows: The concept of auxin as only a cell‐enlargement regulator can no longer accommodate the variety of growth phenomena controlled by auxin. In isolated tissues, auxin interacts with gibberellin in the control of cell enlargement, and auxin and kinin interact in initiating cell division. Some evidence suggests a single site of auxin action for both processes. It is proposed that auxin is not a determining agent but a predisposing agent, causing the production of something in limiting amount which is required in both processes —in the presence of kinin, cell division is activated; in the presence of gibberellin, cell enlargement is activated. In the presence of limiting amounts of auxin, there could be competition between the 2 processes, the outcome depending on the balance of kinin and gibberellin. The possibility of competition in the presence of supraoptimal auxin concentrations is also suggested. Difficulties arise in the application of this concept to observations on intact plants, where cause and effect relationships are not readily established; the use of excised plant parts shows the relationships more clearly. The role of auxin in cell and organ differentiation is also discussed. The primary auxin reaction is not yet known. The biological assay for auxins is discussed with reference to this and to natural auxins. The function of auxin in the correlation of tissue and organ growth through the auxin transport system is stressed, and it is pointed out that if transport is a necessary requirement of a native auxin, indole‐3‐acetic acid is at present the only substance known to qualify.
CHROMOSOMES AND CROSSING BEHAVIOR OF HIBISCUS CANNABINUS, H. ACETOSELLA, AND H. RADIATUS
Authors: Menzel Margaret Y. , Wilson F. D.
Published: January 2018

Menzel, Margaret Y. (Florida State U., Tallahassee), and F. D. Wilson. Chromosomes and crossing behavior of Hibiscus cannabinus, H. acetosella, and H. radiatus. Amer. Jour. Bot. 48(8): 651–657. Illus. 1961.—Chromosomes of diploid H. cannabinus L. (kenaf) form 18 bivalents at metaphase I. In autotetraploid H. cannabinus (2n = 72), more than 50% of the chromosomes pair as trivalents or quadrivalents. In the tetraploid species H. radiatus Cav. and H. acetosella Welw. ex Hiern (H. eetveldeanus De Wild. & Dur.) (2n = 72), only 4% of the chromosomes pair as multivalents and the rest pair as bivalents. Vigorous, highly fertile F1 hybrids between H. acetosella and H. radiatus are easily obtained, show complete chromosome pairing, and give rise to a freely segregating, vigorous, fertile F2: apparently the parental species have similar genome constitutions and are closely related. Chromosome pairing in the triploid hybrids of H. radiatus and H. acetosella with H. cannabinus, in hexaploids obtained by doubling the chromosome number of H. acetosella‐cannabinus F1, and in pentaploid and tetraploid backcrosses of the hexaploids to H. cannabinus shows that the tetraploid species each contain 1 genome (A) very similar to, but not identical with, that of H. cannabinus and 1 dissimilar genome (B). Morphology, fertility, and other characteristics of the various hybrids are discussed in connection with the problem of recombining the resistance to root‐knot nematodes found in the tetraploid species with the desirable fiber properties of H. cannabinus.
GENETICS OF SORDARIA FIMICOLA. IV. LINKAGE GROUP I
Authors: El‐Ani Arif S. , Olive L. S. , Kitani Y.
Published: January 2018

El‐Ani, Arif S., L. S. Olive, and Y. Kitani. (Columbia U., New York City.) Genetics of Sordaria fimicola. IV. Linkage group I. Amer. Jour. Bot. 48(8): 716–723. Illus. 1961.—A general technique for isolating and testing various morphological mutants induced by X ray is described. Eleven mutants differing in ascospore color, fertility, and rate and type of growth were studied in different crosses. This has led to the construction of the first linkage group in S. fimicola. The chromosome on which the 11 mutant loci occur is marked by a single locus on one arm and 10 on the opposite arm. The ascospore color mutant gray is autonomous, maintaining the mutant spore color in both homozygous and heterozygous asci, whereas milky, the other color mutant studied. expresses its mutant effect only in asci homozygous for the factor. Certain crosses involving 2 sterility mutants controlled by 2 non‐allelic loci are fertile, and the progeny give rise to parentals as well as double‐mutant and fertile recombinants.
SPONTANEOUS PARTIAL ROTATION AND OSCILLATION OF THE PROTOPLASM IN COLEOCHAETE AND OTHER CHLOROPHYCEAE
Authors: Geitler Lother
Published: January 2018

Geitler, Lothar. (Botanisches Institut, Universität, Wien, Austria.) Spontaneous partial rotation and oscillation of the protoplasm in Coleochaete and other Chlorophyceae. Amer. Jour. Bot. 48(8): 738–741. 1961.—In certain differentiated cells, such as the hairs, zoosporangia, oogonia, but also in the unicellular germlings, of species of Coleochaete, Chaetotheke, and Chaetosphaeridium, there occurs regularly a spontaneous movement of the protoplasm, which expresses itself strikingly in rapid rotation or oscillation of the chromatophore. The movement occurs partially and localized in certain parts of the cell. It is comparable to no type of protoplasmic streaming known up to the present. Rotation and oscillation occur as regular, cell‐specific attributes, but rotation may be converted experimentally and transiently into oscillation. Oscillation is an intermittent rotation with periodic change of direction. Exploratory researches concerning osmotic values and permeability do not yet reveal definite relationships between the several types of movement in various specialized cells and their physiological condition. However, only the hair cells of Coleochaete and Chaetotheke with rotation show selective vital‐staining with neutral red; the similarly constructed ones of Chaetosphaeridium with oscillation do not.
STUDIES ON THE FLORAL HISTOGENESIS AND PHYSIOLOGY OF PERILLA. II. FLORAL INDUCTION IN CULTURED APICAL BUDS OF P. FRUTESCENS
Authors: Raghavan V. , Jacobs W. P.
Published: January 2018

Raghavan, V., and W. P. Jacobs. (Princeton U., Princeton, N. J.) Studies on the floral histogenesis and physiology of Perilla. II. Floral induction in cultured apical buds of P. frutescens. Amer. Jour. Bot. 48(9): 751–760. Illus. 1961.—The morphological and histological changes induced in apical buds and explants of P. frutescens (L.) Britt. var. ‘Tall Late’ in short days and long days when cultured in White's medium have been followed. When photoinduced in culture, apical buds showed visible signs of changes in 30.9 days, and produced normal flowers in 81.6 days. Apical buds in LD showed similar transformations at the apices, but with continued LD treatment, they elongated to form sterile structures, superficially resembling Selaginella cones. The normal flowers formed in culture were similar to those formed on the intact plant, while the individual florets of the LD‐cone differentiated only the non‐sporogenous tissues in them. A less pronounced sequence of changes resulted when apical buds stripped of their older pairs of apical leaves were LD‐ or SD‐treated. When explants with the 1st pair of unfolded leaves or with the 1st and 2nd pairs of unfolded leaves were photoinduced in vitro, the responses were relatively fast. However, explants with the 1st and 2nd pairs of unfolded leaves in LD remained entirely vegetative. When unfolded leaves were implanted in the same medium separated from the buds and both were photoinduced or given LD, the buds formed the typical 1st signs, but did not differentiate into normal flowers. This inhibition of flowering resulted in the formation of sterile cones, consisting of florets with non‐sporogenous tissues only. The results have suggested the possibility of the sterile cone‐like structures being an intermediate stage in the flowering of Perilla. The role of a possible inhibitor produced by mature leaves of SD plants in LD is discussed.
THE RELATIONSHIP OF M‐INOSITOL TO MORPHOLOGY IN NEUROSPORA CRASSA
Authors: Shatkin A. J. , Tatum E. L.
Published: January 2018

Shatkin, A. J., and E. L. Tatum. (The Rockefeller Institute, New York 21, New York.) The relationship of m‐inositol to morphology in Neurospora crassa. Amer. Jour. Bot. 48(9): 760–771. Illus. 1961.—The role of m‐inositol and its relationship to morphology in Neurospora crassa have been examined. The growth pattern of the inositolless mutant has been found to be a function of concentration of carbon and nitrogen sources and m‐inositol, utilizability of carbon source, ratio of concentrations of sugar to m‐inositol, and size of conidial inoculum. Inhibition of mycelial m‐inositol uptake has been demonstrated for a number of carbon sources, and the ability of a particular compound to inhibit m‐inositol uptake found to be directly related to both its effectiveness as an energy source and its effect on the morphology of the inositol‐requirer. Results of cell‐fractionation experiments and autoradiography have shown that phospholipid inositol is widely distributed in the hyphae and not bound in a single subcellular organelle. Electron micrographs of cell fractions indicate that inositol is a structural constituent of N. crassa lipoprotein membranes, including plasmalemma, nuclear envelope, mitchondrial membranes, and endoplasmic reticulum. Normal inositol‐requiring and wild‐type hyphae are similar in ultrastructure. However, sub‐optimally cultured, colonial, inositolless hyphae contain large lipid droplets, and the cellular membranes are in various stages of degeneration. Chemical evidence indicates that colonial hyphae do not synthesize more fat than normal hyphae, suggesting that the lipid droplets are products of membrane catabolism. It is proposed that the colonial morphology of the inositol‐requiring mutant of N. crassa is due to a metabolic imbalance between membrane synthesis and the synthesis of other cellular constituents.
A NEW FUNGUS ON CYPERUS IRIA
Authors: Thind K. S. , Rawla G. S.
Published: January 2018

Thind, K. S., and G. S. Rawla. (Panjab U., Chandigarh, India.) A new fungus on Cyperus iria. Amer. Jour. Bot. 48(10): 859–862. Illus. 1961—Duosporium cyperi gen. et sp. nov., collected on Cyperus iria Linn., is characterized by the production of 2 types of conidia, macroconidia and microconidia. The macroconidia are straight, cylindrical, triseptate, with their middle cells dark brown, long, thick‐walled, and end cells much paler or subhyaline, short, thin‐walled, the middle and the end cells being equally wide. The microconidia are nonseptate, spherical, dark brown, prominently verrucose, and produced apically on the conidiophores like the macroconidia; occasionally also formed as secondary conidia on germinating 3‐septate macroconidia in culture. The formation of 2 distinct types of conidia in Duosporium and the features of its macroconidia characteristically differentiate it from its close relative Helminthosporium, although Duosporium. cyperi is not unique among fungi in producing 2 types of conidia.
KARYOTYPES OF IRIS SPECIES INDIGENOUS TO THE USSR
Authors: Randolph L. F. , Mitra Jyotirmay
Published: January 2018

Randolph, L. F., and Jyotirmay Mitra. (Cornell U., Ithaca, N. Y.) Karyotypes of Iris species indigenous to the USSR. Amer. Jour. Bot. 48(10): 862–870. Illus. 1961.—The present center of diversity of the more than 200 species of Iris is in the eastern Mediterranean area of the Balkans and western Asia, with extensions of several important sections of the genus northeastward into the USSR. Karyotype analyses by the authors, previously limited chiefly to European, western Asian and American species, in this study included 10 tall bearded, dwarf bearded, regelia and oncocyclus species obtained from the USSR. A higher number of metacentric chromosomes was found in I. albertii than in any Iris species studied previously, suggesting a primitive status for this species, according to the Lewitsky concept of karyotype evolution. The 24‐chromosome dwarfs, I. timofejewii and scariosa, also have more metacentric chromosomes than do Balkan dwarf species with the same chromosome number. Pumila dwarfs of the USSR have either 30, 31, or 32 chromosomes, and evidence of the mechanism concerned in this variation in number was obtained. A rare case of somatic translocation involving non‐homologous acrocentric chromosomes was observed, and its significance as a source of chromosomal mutants was considered. The regelia species, I. longiscapa, rarely seen in cultivation, was found to have 18 chromosomes, which is a new number for a regelia species. The oncocyclus species, I. elegantissima and paradoxa, have karyotypes similar to those of other oncocyclus species studied previously. The potential value of Russian species of Iris in the production of more winter‐hardy and otherwise desirable new kinds of garden hybrids is discussed.
LABORATORY CULTIVATION OF CLASTODERMA DEBARYANUM
Authors: McManus Mary Annunciata
Published: January 2018

McManus, Sister Mary Annunciata, R.S.M. (Mount Mercy Coll., Cedar Rapids, Iowa.) Laboratory cultivation of Clastoderma debaryanum. Amer. Jour. Bot. 48(10): 884–888. Illus. 1961.—Clastoderma debaryanum has been cultivated on laboratory media for the first time and its life cycle studied. Spores germinate to produce a single protoplast which may remain a myxamoeba or may become a swarm cell. The swarm cells fuse in pairs to form a zygote, which grows into a microscopic, spherical plasmodium. The plasmodium never develops a network of veins and shows only irregular streaming. At maturity each plasmodium gives rise to 1 sporangium. There is always a sphere of gelatinous material about 4/5 the distance up the stalk, which appears late in the development of the sporangium, and which dries to become a wrinkled enlargement. The peridium dehisces early, leaving only a few plates attached to some of the peripheral tips of the capillitial twigs, and a peridial collar. The solid capillitium branches from the tip of a very short columella.
A LIGHT‐ AND ELECTRON‐MICROSCOPIC SURVEY OF ALGAL CELL WALLS. I. PHAEOPHYTA AND RHODOPHYTA
Authors: Dawes Clinton J. , Scott Flora M. , Bowler E.
Published: January 2018

Dawes, Clinton J., Flora M. Scott, and E. Bowler. (U. California, Los Angeles.) A light‐ and electron‐microscopic survey of algal cell walls. I. Phaeophyta and Rhodophyta. Amer. Jour. Bot. 48(10): 925–934. Illus. 1961.—An introductory survey of the structure of the cell walls of brown, red, and green algae, as seen under light and electron microscopes, has been completed. In the present paper (Part I) the structure of the thalli of the Phaeophyta and Rhodophyta is compared, and the occurrence of intercellular spaces, pitting, and microfibrillar patterns is discussed. A detailed comparison of the cell‐wall structure and growth of a brown alga, Dictyota flabellata, and of a red alga, Helminthocladia californica, is also presented. In Dictyota, typical of the brown algae, the microfibrillar pattern in the apical cells and in the adjacent cells of the thallus tip is reticulate. In mature cells, the microfibrils are dominantly parallel in orientation. Pits, which are fields of closely set pores, are distinctive. The microfibrils in the pit areas are masked by non‐fibrillar material. Helminthocladia, with a cell wall characteristic of the red algae, differs from Dictyota in that the microfibrillar pattern is reticulate at all ages of the cell and throughout the thallus. In the pit areas, the microfibrils are not masked by amorphous material. Pit connections, characteristic of the Florideae, can be divided into 2 major groups. Either the pit connection is an open channel between 2 adjacent cells, or it is composed of numerous plasmodesmata traversing a continuous, loose, microfibrillar wall. The techniques of the survey are emphasized in that fragmented cell walls were studied, and, also, chemically cleared material was constantly compared with fresh material under light and electron microscopes. It is concluded that the cell wall, as a taxonomic character, is of value only in delimiting the Phaeophyta and Rhodophyta.
ISOLATION, GROWTH, AND RESPIRATION OF A THERMOPHILIC BLUE‐GREEN ALGA
Authors: Holton Raymond W.
Published: January 2018

Holton, Raymond W. (U. Texas, Austin.) Isolation, growth, and respiration of a thermophilic blue‐green alga. Amer. Jour. Bot. 49(1): 1–6. Illus. 1962.—The isolation of a bacteria‐free culture of Hapalosiphon laminosus (= Mastigocladus laminosus) from an algal mass obtained from Liard Hot Springs, British Columbia, is described. Seven different bacterial media at 2 incubation temperatures were used to test for bacteria in suspensions of partially broken up algae. The algal growth rate was obtained by calculating the slope of the straight line obtained in a plot of the cube root of the dry wt against time. In cultures aerated with air the growth was optimal between 35 and 50 C, with an upper limit at 55 and a lower limit at 25. Aeration with 1% CO2 in air significantly increased growth rates and the optimum was at 45–50 C. Unaerated flasks grew more slowly than aerated ones. The endogenous Qo2 (in μl/hr–mg dry wt) at 45 was 8.0 for growing cells and 2.8 for starved cells kept in darkness 18 hr. The Qo2 was maximal between pH 7.0 and 8.5. The concentration of phosphate buffer affected the Qo2 and rates in 0.02 M were slightly greater than those in distilled water and much greater than those in 0.4 M. The Qo2 of growing cells was slightly stimulated by 2,4‐dinitrophenol (DNP), whereas glucose or glucose plus DNP did not affect it. In contrast, the endogenous Qo2 of starved cells was nearly doubled in glucose and tripled in DNP plus glucose.
AN ELECTRON MICROSCOPE STUDY OF SILVER NITRATE REDUCTION IN LEAF CELLS
Authors: Brown W. V. , Mollenhauer H. , Johnson C.
Published: January 2018

Brown, W. V., H. Mollenhauer, and C. Johnson. (U. Texas, Austin.) An electron microscope study of silver nitrate reduction in leaf cells. Amer. Jour. Bot. 49(1): 57–63. Illus. 1962.—As reported earlier in many studies, AgNO3 is reduced quickly by the living chloroplasts of angiosperms. Electron microscope study has resolved the conflict of opinions concerning the exact location of the silver particles. Reduction of AgNO3, as indicated by location of silver particles, occurs within the chloroplasts but not within the grana or pure stroma; it appears to be associated with the intergranal (also called stroma) lamellae. Silver particles are formed also at the surfaces of the cell wall, both in the middle lamella and at the inner surface, and also within plasmodesmata. It is concluded that chlorophyll is probably not involved directly in the reduction. There is some slight support for the popular hypothesis that ascorbic acid may be the chief reducing agent.