bluuebunny/crossref_metadata_2025 huggingface dataset:
Two‐Step One‐Pot Synthesis of Unsymmetrical (Hetero)Aryl 1,2‐Diketones by Addition‐Oxygenation of Potassium Aryltrifluoroborates to (Hetero)Arylacetonitriles
Authors: Kumar Yogesh , Jaiswal Yogesh , Kumar Amit
Published: January 2018

An efficient one‐pot two‐step procedure for the synthesis of unsymmetrical (hetero)aryl 1,2‐diketones has been developed. The reaction proceeds through a palladium‐catalyzed nucleophilic addition of potassium aryltrifluoroborates to aliphatic nitriles followed by a copper‐catalyzed aerobic benzylic C–H oxygenation using molecular oxygen as a green oxidant. This represents the first example of the direct synthesis of unsymmetrical diaryl 1,2‐diketones from arylacetonitriles. This method utilizes inexpensive, stable, nontoxic, and readily available starting materials, is highly effective in the presence of both electron‐rich and electron‐poor nitriles and aryltrifluoroborates, and tolerates a wide variety of functional groups. The synthetic utility of this transformation was shown by increasing the scale of the reaction and by carrying out the one‐pot protocol for the preparation of quinoxaline and benzimidazole derivatives. A plausible reaction mechanism has also been proposed.
Ruthenium‐Catalyzed Direct Transformation of Alkenyl Oximes to 5‐Cyanated Isoxazolines: A Cascade Approach Based on Non‐Stabilized Radical Intermediate
Authors: Wang Dan‐Jun , Chen Bei‐Yi , Wang Yi‐Qi , Zhang Xiao‐Wei
Published: January 2018

A ruthenium‐catalyzed ammoxidation of alkenyl oximes under mild and neutural condtions is described. In this method, tert‐butyl nitrite plays a dual role, acting as an oxidant as well as a nitrogen source. This reaction avoids using any toxic radical initiators or cyanide reagents. This convenient and practical method offers an easy access to 5‐cyanated isoxazolines in good to high yields, and shows good functional group tolerance and high efficiency. It is rather remarkable that this new reaction provides a strategically distinct approach based on non‐stabilized radical intermediate and constructs C–O and C≡N triple bonds in a single‐step. Moreover, the difunctionalization of unactivated olefins bearing oximes has been realized.
Effects of natural weathering on the fire properties of intumescent fire‐retardant coatings
Authors: Bahrani Babak , Hemmati Vahid , Zhou Aixi , Quarles Stephen L.
Published: January 2018

Fire‐retardant coatings could be one option for providing enhanced protection to buildings during a wildfire, particularly when applied to combustible siding and in under‐eave areas. Limited studies have been conducted on their effectiveness but maintaining adequate performance after weathering has been questioned. This paper reports on a study evaluating the effect of natural weathering on the performance of intumescent‐type fire‐retardant coatings. The main concerns were (a) the reduction of ignition resistance of the coating after weathering and (b) the coating might contribute as a combustible fuel and assist the fire growth after weathering. This study evaluated the performance of 3 intumescent coatings that were exposed to natural weathering conditions for up to 12 months. A bench‐scale evaluation using a cone calorimeter was used to evaluate the performance of the coatings at 3 heat flux levels (30, 50, and 70 kW/m2). Our results showed that weathering exposure reduced the effectiveness of fire protection of intumescent coatings, but the weathered coatings did not act as additional fuels. Weathering orientation showed much less effect on the performance of intumescent coatings in comparison to other parameters. There was statistical evidence that weathering duration, heat flux level, and coating type affected the combustion properties.
Head and neck lymphedema management: Evaluation of a therapy program
Authors: Pigott Amanda , Nixon Jodie , Fleming Jennifer , Porceddu Sandro
Published: January 2018

Background

The purpose of this pilot study was to examine a therapeutic intervention for head and neck lymphedema. The 22‐week intervention involved therapist‐led care and participant self‐management. Effectiveness was evaluated using a previously described lymphedema assessment tool, the Assessment of Lymphedema of the Head and Neck (ALOHA) to detect change over the course of the 22 weeks of treatment, and before and after a single treatment session.

Methods

A prospective observational pilot study was conducted with a cohort of 10 participants assessed. Measurements of size (tape measurements) and water content (tissue dielectric constant [TDC]) were used, per the ALOHA protocol. Participants received 13 lymphedema therapy treatments at reducing frequencies over 22 weeks and daily self‐management.

Results

There was an overall significant reduction in lower neck circumference (F [2.15,19.35] = 7.11; P = .004), upper neck circumference (F [5,45] = 7.27; P < .001) and TDC (F (5,45) = 8.92; P < .001) over time. There were no significant differences over the course of treatment for mean ear‐to‐ear measurements or before and after a single session of treatment.

Conclusion

This pilot study found a reduction in head and neck lymphedema over the 22‐week lymphedema treatment course. This intervention may be successful in reducing head and neck lymphedema; however, further studies are needed to investigate these findings in a larger sample with the use of a control group to negate improvements from healing over time.
Extended endonasal approach versus maxillary swing approach to the parapharyngeal space
Authors: Roger Vivien , Patron Vincent , Moreau Sylvain , Kanagalingam Jeeve , Babin Emmanuel , Hitier Martin
Published: January 2018

Background

The nasopharyngeal and parapharyngeal spaces are difficult for surgeons to access. Of the various external routes described, the maxillary swing has emerged as the gold standard because of its simplicity. However, its morbidity has led to the development of less invasive techniques. The purpose of our study was to compare the surgical anatomy of the maxillary swing with that of the endoscopic endonasal approach.

Methods

Each procedure was performed on 10 anatomic specimens. The exposure and the limits obtained were evaluated. A CT scan analysis was performed.

Results

The endoscopic endonasal approach extended the limits, offering wider exposure. The endoscopic endonasal approach made possible better visualization of deep structures and precise dissection of the parapharyngeal spaces. However, the maxillary swing provided better access to the oropharynx and could be completed 3 times faster.

Conclusion

The endoscopic endonasal approach provides excellent exposure, a wide dissection range, and precise definition of anatomic structures, making it an alternative of choice rather than the maxillary swing approach.
GENETICS AND DEVELOPMENT OF AN UNSTABLE CHLOROPHYLL DEFICIENCY IN LYCOPERSICON ESCULENTUM
Authors: Rick Charles M. , Thompson Anson E. , Brauer Oscar
Published: January 2018

Rick, Charles M. (U. California, Davis.), Anson E. Thompson, and Oscar Brauer. Genetics and development of an unstable chlorophyll deficiency in Lycopersicon esculentum. Amer. Jour. Bot. 46(1) : 1‐11. Illus. 1959.—A single gene gh determines a condition of variable chlorophyll deficiency in the tomato. Two independent mutations have been recorded at this locus, and both mutants exhibit the same phenotype. Linkage tests ascertained that the locus of gh lies between hl and j in group V. Graft and inoculation experiments prove that the gh phenotype is not caused by a virus. The mutant seedlings have cotyledons that can be identified by their partial chlorophyll deficiency. First true leaves may rarely have normal morphology and pigmentation; in most seedlings they show a mosaic of normal and chlorotic tissue. With subsequent growth, the plant rapidly reaches a condition of complete chlorophyll deficiency. Two constant levels of deficiency have been observed: a common white phase with very little or no chlorophyll and an infrequent yellow phase with about 5% of the normal chlorophyll content present in irregularly distributed chloroplasts. In both phases leaf lamina structure is drastically modified; petioles, stems, flowers, and fruits are much less affected. Sporadic islands of normal green coloration appear in the otherwise stable white or yellow phase. The degree of chlorophyll development is subject to great environmental modification but no evidence was obtained for genetic control in addition to the determination by gh. Depending upon environment, most gh seedlings perish before fruiting, but those with sufficient chlorophyll flower and set fruits with seeds after self‐or cross‐pollination. Most gh fruits remain white until mature, when the normal yellow epidermal pigment appears, the interior remaining white; occasional streaks or patches of chlorophyll that develop on immature fruits turn reddish at maturity. Seeds from such sectors, like all other seeds harvested from selfed gh plants, give rise only to gh progeny, thereby rendering improbable a mutational basis for the sporadic reversions to green. Applications of gh to further genetic and physiological studies are discussed.
CYTOLOGICAL INVESTIGATIONS OF KABATIELLA CAULIVORA
Authors: Cole Herbert , Couch Houston B.
Published: January 2018

Cole, Herbert, Jr., and Houston B. Couch. (Penn. State U., University Park.) Cytological investigations of Kabatiella caulivora. Amer. Jour. Bot. 46(1) : 12‐16. Illus. 1959.—Initial growth of K. caulivora on artificial media is characterized by budding, yeast‐like, conidia, exclusive of mycelia. After 14 days growth, at 20°C., mycelial growth becomes macroscopically evident. A study of the germination behavior of a total of 5500 conidia from the initial yeast‐like growth stage showed 59 to germinate by the production of mycelia, while the balance germinated by budding. Five thousand conidia of the mycelial growth type were studied in a successive, single‐spore transfer series, and, in all cases, conidial germination continued to be by means of germ tubes. Conidia of both growth forms were studied by means of bright field and phase contrast microscopy, and found to be multinucleate—possessing variable nuclear numbers, ranging from 1‐8 per cell. Mean nuclear number for both the mycelial and conidial types was 2.8. All nuclei of both growth types appeared to contain the same chromosome complement. The cultural variability exhibited by K. caulivora cannot be reconciled with the concept of dual phenomenon. It is suggested, rather, that the mycelial homotype probably arises as the result of a unidirectional mutation within the conidial growth form.
RADIOMYCES, A NEW GENUS IN THE MUCORALES
Authors: Embree Robert W.
Published: January 2018

Embree, Robert W. (U. California, Berkeley.) Radiomyces, a new genus in the Mucorales. Amer. Jour. Bot. 46(1): 25‐30. Illus. 1959.—Radiomyces spectabilis is described as a new genus and species in the order Mucorales of the Phycomycetes. This fungus readily grows in pure culture, and developmental stages of the asexual and sexual reproductive structures are described. The genus is referred to the family Thamnidiaceae, and in doing so, the family concept is necessarily broadened to include almost colorless, smooth‐walled zygospores with appendiculate suspensors.
HISTOLOGY OF MALFORMATIONS PRODUCED ON BEAN PLANTS BY CULTURE FILTRATE OF ASPERGILLUS NIGER
Authors: Postlethwait S. N. , Curtis Roy W.
Published: January 2018

Postlethwait, S. N., and Roy W. Curtis. (Purdue U., Lafayette, Ind.) Histology of malformations produced on bean plants by culture filtrate of Aspergillus niger. Amer. Jour. Bot. 46(1) : 31‐35. Illus. 1959.—The stem and leaf petioles of bean seedlings treated with culture filtrates of A. niger exhibit severe curvatures, increased diameter, reduced length, and irregular protrusions. These malformations result from an apparent partial loss of polarity of the cells in the actively growing region of young internodes and petioles. Enlargement and multiplication of cells in the affected regions occur mostly at an angle to the longitudinal axis of the plant. The effect is localized and the portion of the plant produced from the apical meristem subsequent to treatment matures in a normal way.
CHEMICAL CHANGES IN LESPEDEZA ASSOCIATED WITH INDUCED POLYPLOIDY
Authors: Hanson C. H. , Cope W. A. , Brinkley R. M.
Published: January 2018

Hanson, C. H. (U.S.D.A., Beltsville, Md.), W. A. Cope and R. M. Brinkley. Chemical changes in Lespedeza associated with induced polyploidy. Amer. Jour. Bot. 46(1): 36‐39. 1959.— Changes in the quantities of 5 chemical constituents which were associated with induced polyploidy were studied using leaves of the following polyploids: Autotetraploids—Lespedeza cuneata, L. latissima, L. stipulacea, and L. striata; amphidiploids—L. hedysaroides × L. cuneata and L. latissima × L. cuneata. L. stipulacea and L. striata were annuals with low concentrations of tannin; the other species were perennials and high in tannin content. The polyploids were generally lower in crude protein, P2O5, and CaO, and higher in K2O and total tannin. The greatest and most significant shift was in total tannin. Induced polyploids of Lespedeza did not appear promising as forage plants.
CHROMOSOME NUMBERS IN THE LEGUMINOSAE II: AFRICAN SPECIES, INCLUDING PHYLETIC INTERPRETATIONS
Authors: Turner B. L. , Fearing O. S.
Published: January 2018

Turner, B. L., and O. S. Fearing. (U. Texas, Austin.) Chromosome numbers in the Leguminosae. II. African species, including phyletic interpretations. Amer. Jour. Bot. 46(1) : 49‐57. Illus. 1959.—Chromosome numbers for 30 African legume species have been reported. These include first reports for 28 taxa, including 12 genera (Bolusanthus, Calpurnia, Melolobium, Lessertia, Sulherlandia, Colophospermum, Guibourtia, Burkea, Julbernardia, Schotia, Piliostigma and Swartzia). The counts are discussed with respect to those previously reported for related groups, and this chromosomal information was used to construct hypothetical phyletic lines at the tribal level within the subfamilies Papilionoideae and Caesalpinioideae. A phyletic scheme for the Leguminosae (excluding the Mimosoideae) based on this evidence from chromosome studies is presented. Notable departures from previously suggested phyletic treatments include: (1) Suggestion for inclusion of genera of the Galegeae and Hedysareae with base numbers of x = 10 and 11 with the Phaseoleae and Dalbergieae. (2) Derivation of the Papilionoideae through caesalpinoid prototypes, possibly from Swartzia‐like ancestors. (3) Recognition of several very old chromosomal lines stemming from the subfamily Caesalpinioideae, and the suggestion that parts of the tribes Sclerolobieae, Cynometreae, Swartzieae and Sophoreae are, perhaps, more closely related to each other and to the Papilionoideae than they are to the remaining caesalpinoid tribal lines.
PROTEIN SYNTHESIS AND THE CONTROL OF PLANT PROCESSES
Authors: Bonner James
Published: January 2018

Bonner, James. (California Inst. Technology, Pasadena.) Protein synthesis and the control of plant processes. Amer. Jour. Bot. 46(1) : 58‐62. Illus. 1959.—Microsomal ribonucleoprotein particles which occur in the cytoplasm of plant, animal, and microbial cells alike, possess the function of protein synthesis, and appear to be responsible for the formation of many, perhaps all, of the soluble cytoplasmic proteins. To the process the microsome contributes information, arranging previously acyl‐activated amino acid residues in the abundance and sequence characteristic of the specific enzyme being synthesized. The microsome consists of RNA and of protein. The latter appears to be a structural protein, common to microsomes and not directly related to the protein synthesized by the microsome. The amount of information contained in the RNA of a microsomal particle can be calculated to be sufficient for the synthesis of one or at the most a few species of protein molecules. There must therefore be within the cytoplasm of the cell many different species of microsomes, superficially alike, but each different species bearing in RNA code the information required for the assemblage of but one or a few kinds of protein molecules. Microsomes do not, so far as can be judged, possess the power to reproduce. On the contrary microsomal RNA, and possibly microsomal protein also, appear to be synthesized within the nucleus. Transfer of microsomes from nucleus to cytoplasm is therefore implied and is in fact suggested by a variety of indirect experiments. The transfer of nuclear information to the cytoplasm may well be mediated by the microsomes.
THE EFFECT OF SHORT PERIODS OF HIGH TEMPERATURE DURING DAY AND NIGHT PERIODS ON PEA YIELDS
Authors: Karr E. J. , Linck A. J. , Swanson C. A.
Published: January 2018

Karr, E. J. (Ohio State U., Columbus), A. J. Linck, and C. A. Swanson. The effect of short periods of high temperature during day and night periods on pea yields. Amer. Jour. Bot. 46(2) : 91‐93. Illus. 1959.—The effect of high temperatures during periods of relatively short duration (3‐4 days) at various stages following anthesis at the first bloom node was studied in relation to yield of peas at this node. Except for the periods of differential temperature treatments, the plants were maintained in a standard environment room (24°C., light, 12 hr.; 15°C., darkness, 12 hr.). Three different temperature regimes during the treatment periods were studied: high day temperature—standard night temperature (32°—15°C.) ; standard day temperature—high night temperature (24°—30°C.) ; and high day and night temperatures combined (32°—30°C.). The data reveal the existence of a relatively well‐defined thermal‐sensitive period, with maximal sensitivity to high day temperatures occurring at about 9‐11 days from full bloom, and maximal sensitivity to high night temperatures occurring about 6‐9 days from full bloom. High night temperatures proved more critical, resulting in a maximal reduction of 25% in yield, as opposed to about 8% for high day temperatures. The effect of high day and night temperatures combined tended to be roughly additive.
KARYOTYPES OF IRIS PUMILA AND RELATED SPECIES
Authors: Randolph L. F. , Mitra Jyotirmay
Published: January 2018

Randolph, L. F. and Jyotirmay Mitra. (Cornell U., Ithaca.) Karyotypes of Iris pumila and related species. Amer. Jour. Bot. 46(2): 93‐102. Illus. 1959.—The karyotypes of 30‐ and 32‐chromosome geographical variants of the amphidiploid I. pumila from Russia and the Balkans were compared with the karyotype of the typical 32‐chromosome Austrian forms of this species and with those of the diploid I. attica and I. pseudopumila, previously reported to be the basic species from which I. pumila originated. Plants from 3 collections of a Crimean form of I. pumila with 32 chromosomes had a pair of long chromosomes with submedian centromeres morphologically similar to chromosome 1 of the typical form of I. pumila. In addition, there was another heteromorphic pair of submedian chromosomes with one of the members having a shorter short arm. The manner in which this altered chromosome could have arisen as a result of a heterobrachial inversion is described. Five different collections of I. pumila with 30 chromosomes from Russia differ in several respects from the typical 32‐chromosome I. pumila. They have an unusually long pair of chromosomes with a submedian centromere and a secondary constriction in the long arm. This chromosome is the original chromosome 2 which had been altered by the addition of a segment equivalent to the most of the long arm of one of the shorter chromosomes with subterminal centromere. The manner in which this could have occurred as the result of unequal reciprocal translocation is described. Loss of the remaining diminutive portion of the short chromosome with subterminal constriction assumed to have been involved in the unequal interchange of segments producing the modified, longer chromosome 2 would account for the reduction in chromosome number from 32 to 30 in the Russian form of I. pumila. Four pairs of chromosomes with satellites have been found in the 30‐chromosome plants whereas 6 pairs of satellited chromosomes are present in the 32‐chromosome I. pumila. The spontaneous occurrence of chromosomal alterations of the type here described are considered to be significant factors in the process of chromosomal repatterning resulting in the appearance of new geographical races, and eventually of species of iris, with altered chromosome numbers and modified karyotypes. More specifically it is concluded that amphidiploidy accompanied by chromosomal repatterning resulting from segmental interchange, heterobrachial inversion and related types of chromosomal alterations has played an important role in the evolution of I. pumila and karyological forms of this species occupying different geographical areas.
RADIATION DAMAGE IN SHOOT APICES OF CONCORD GRAPE
Authors: Pratt Charlotte
Published: January 2018

Pratt, Charlotte. (N. Y. State Agri. Expt. Sta., Geneva.) Radiation damage in shoot apices of Concord Grape. Amer. Jour. Bot. 46(2) : 103‐109. Illus. 1959.—Dormant rooted cuttings of ‘Concord’ grape were exposed either to 200‐6000 r of X rays or to 2‐6 hr. of thermal neutrons (average total dose of 4.80 × 1011 to 1:59 × 1013 neutrons/cm.2). Percentage of plants surviving in the field tended to decrease with dosage beginning with 2000 r of X rays or 2 hr. of thremal neutrons. It showed a sharp drop in lots which had received doses of 4000 r of X rays or 4 hr. of thermal neutrons. Frequency of hudless shoots (shoots lacking a terminal bud after the first leaves emerged) increased with dosage, beginning with groups which had received 2000 r of X rays or 2 hr. of thermal neutrons. Microscopic examination of radiation‐damaged shoot apices showed one or more of the following characteristics: (1) shape and organization of the apical meristem different from that of the untreated shoot apex, which is described; (2) no young primordia; (3) acropetal advance of maturation of cells; in 4 cases cells with spirally thickened, lignified walls were found 1‐4 cells deep in the meristem; (4) collapse of cells in the tunica and corpus; formation of periderm and deeper, cambium‐like divisions below the wound; (5) site of the former apical meristem either carried up on the base of a single terminal leaf or remaining a flat area between terminal leaves. Aspects of radiation sensitivity of the shoot and theories of shoot organization with reference to natural and induced chimeras are discussed.
THE DEVELOPMENT AND CYTOLOGY OF THE EPIBIOTIC PHASE OF PHYSODERMA PULPOSUM
Authors: Lingappa Yamuna
Published: January 2018

Lingappa, Yamuna. (U. Michigan, Ann Arbor.) The development and cytology of the epibiotic phase of Physoderma pulposum. Amer. Jour. Bot. 46(3) : 145‐150. Illus. 1959.—Physoderma pulposum, a chytrid parasite on Chenopodium album L. and Atriplex patula L., has a zoosporangial epibiotic phase. The latter consists of extramatrical sporangia and intramatrical bushy rhizoids, both enclosed in large protruding galls. The sporangia are subspherical, up to 350μ in diameter, and may produce hundreds of planospores. If planospores settle on the host surface, they develop narrow germ tubes which penetrate the epidermal cells and develop into rhizoids. The planospore body, however, remains on the host surface and develops into a mature epibiotic sporangium in about 20‐25 days at 16°C., 12‐15 days at 20‐25°C., or 6‐8 days at 30°C. During development, its nucleus and daughter nuclei divide mitotically with intranuclear spindles until the sporangium contains several hundred nuclei. This is followed by progressive cleavage which delimits the planospore rudiments. When mature sporangia are placed in fresh water, the planospores are quickly formed within 1 hr. at 25°C. and begin to swarm within the sporangia. They escape in large numbers through an opening formed by the deliquescence of a papillum in the sporangial wall. The planospores are subspherical or elongate, 3‐5 × 4‐6 μ, and each has an eccentric orange‐yellow refractive globule and a flagellum 18‐22 μ in length. The electron micrographs of the flagella indicate that the flagella are absorbed from tip backward during encystment of the planospores. By periodic inoculation of the host plants with planospores from epibiotic sporangia, as well as from germinating resting sporangia, generation after generation of epibiotic sporangia have been obtained for 4 years. This proves the existence of a eucarpic, epibiotic, ephemeral zoosporangial phase in P. pulposum. Field observations on the duration and sequence of development of the fungus indicate that the endobiotic resting sporangial phase always follows the epibiotic phase. The results of infection experiments also indicate that the epi‐ and endobiotic phases belong to one and the same fungus, P. pulposum.
A NEW CORDAITEAN STEM WITH PAIRED AXILLARY BRANCHES
Authors: Baxter Robert W.
Published: January 2018

Baxter, ROBERT W. (U. Kansas, Lawrence.) A new cordaitean stem with paired axillary branches. Amer. Jour. Bot. 46(3) : 163‐169. Illus. 1959.—A cordaitean stem tip from the middle Pennsylvania of Kansas is described as a new species, Mesoxylon birame sp. nov. The most distinctive feature of the new species is the presence of paired branches in the axil of each leaf. The possibility that these twin branches represent axes of Cordaianthus cones is discussed.
SYMMETRY IN EQUISETUM
Authors: Bierhorst David W.
Published: January 2018

Bierhorst, David W. (Cornell U., Ithaca, N. Y.) Symmetry in Equisetum. Amer. Jour. Bot. 46(3) : 170‐179. Illus. 1959.—A total of 118 leaf whorls and corresponding nodes from a total of 9 species of Equisetum were studied in serial cross‐section. The number of whorls having the same leaf number as the 2 adjacent ones was 67. The size of the arc measured in degrees of circumference occupied by each leaf, as well as its position relative to leaves of adjacent whorls were measured. The disposition of the internodal and trans‐nodal vascular strands was determined for each of the nodes. The average per cent deviations from theoretical leaf size within whorls were: whorls not involved in change in leaf number, 3.9; those with fewer leaves than the one below, 9.5; those with more leaves than one above, 7.1; those with more leaves than one below, 9.4; those with different leaf number from the 2 adjacent ones, 12.5. In Equisetum, it is a general rule that (1) a leaf which falls directly above a leaf in the next whorl where the younger whorl possesses fewer leaves than the older one is usually the largest leaf within its whorl, (2) a leaf which falls directly below a leaf in the next younger whorl where the younger whorl possesses fewer leaves than the older one is usually the smallest leaf within its whorl, (3) a leaf which falls directly above a leaf in the next older whorl where the younger whorl possesses a greater number of leaves than the older one is usually the smallest leaf in its whorl, and (4) a leaf which falls directly below a leaf in the next younger whorl where the younger whorl possesses a greater number of leaves than the older one is usually the largest leaf within its whorl. The numerous variations in the disposition of vascular tissue associated with changes in leaf number are described. Double leaf traces which originate in various ways are common, as well as vertical strands traversing the nodes. The leaf trace system is considered to be determined by the number, position, and relative sizes of leaf primordia. The disposition of the trans‐nodal protoxylem seems to be determined to a large extent by the proximity of the leaf traces above and below the node.
THE STRUCTURE AND MANNER OF DIVISION OF THE NUCLEI IN THE VEGETATIVE MYCELIUM OF NEUROSPORA CRASSA
Authors: Bakerspigel Alexander
Published: January 2018

Bakerspigel, Alexander. (New Mount Sinai Hospital, Toronto, Canada.) The structure and manner of division of the nuclei in the vegetative mycelium of Neurospora crassa. Amer. Jour. Bot. 46(3) : 180‐190. Illus. 1959.—A description has been given of the structure and manner of division of the nuclei in the conidia and vegetative mycelium of the ascomycete, Neurospora crassa. This is another example of a fungus in which the vegetative nuclei do not appear to divide in the manner of classical mitosis. Instead, as division proceeds, the chromatin forms complexes of chromosomal filaments which then contract. At the end of division the contracted chromatin constricts and pulls rapidly apart without the aid of a visible spindle. Individually recognizable chromosomes were not observed to align themselves on a metaphase plate. In the vegetative mycelium of N. crassa the central body elongates and divides by constriction at the midregion. Thus at the end of division each of the sister nuclei is composed of a portion of the original chromatin and central body. It is suggested that both the elongating central body and the densely stained granule in the chromatin of these nuclei play significant roles during nuclear division.
ENDOMORPHIC AND ECTOMORPHIC CHARACTERS IN PELECYPHORA AND ENCEPHALOCARPUS
Authors: Boke Norman H.
Published: January 2018

Boke, Norman H. (U. Oklahoma, Norman.) Endomorphic and ectomorphic characters in Pelecyphora and Encephalocarpus. Amer. Jour. Bot. 46(3) : 197‐209. Illus. 1959.—Outstanding ectomorphic characters of Pelecyphora valdeziana include its small size; pectinate, hairy spines; broad, truncate, floral buds; dehiscent, berry‐like fruits; and black, tuberculate seeds. The leaves are vestigial, and although the areole meristem originates on the adaxial face of the tubercle primordium, it is soon elevated to the summit by intercalary growth. The first primordium of the single, elliptical series of spines is initiated immediately in front of the rudimentary leaf. Others form in acropetal sequence on either side of the areole meristem. The last ones form across the areole, leaving a meristem, which may be floral or vegetative, on the anterior side. Whether areoles of P. valdeziana can be considered dimorphic is doubtful. However, they approach the type of dimorphism found in Epithelantha. Pelecyphora aselliformis has acuminate floral buds; dry, papery fruits; and brown, curved, reticulate seeds. The leaves are reduced almost to extinction. The areole meristem becomes separated into spiniferous and axial portions early in ontogeny, but the 2 parts remain connected by a band of trichomes, which probably represents a vestigial groove. The axial meristem may be reproductive or vegetative. The sequence of spine initiation in P. aselliformis is unusual in that it begins at the anterior side of the spiniferous meristem and proceeds toward the posterior side. Areoles in this species are clearly dimorphic, much as in the mammillarias, but the vestigial groove is reminiscent of Coryphantha and related genera. Although adult specimens of Encephalocarpus strobiliformis bear scale‐like tubercles, which are very different from the laterally compressed tubercles of P. aselliformis, their flowers, fruits, and seeds are almost identical. The two species share the same type of areole dimorphism, including the vestigial groove. Tubercles on seedlings and young branches of E. strobiliformis are prismatic rather than scale‐like. Since they tend to be laterally compressed at the summit and bear elliptical areoles with many more spines than the adult, they resemble seedling tubercles of P. aselliformis. Tubercles on adult specimens likewise resemble each other in the structure of the epidermis and hypodermis. It does not seem possible that P. valdeziana can be retained in the genus Pelecyphora. If seed structure has any systematic value, the species belongs in or near the genus Thelocactus, to which it was assigned by Bravo. Pelecyphora aselliformis and Encephalocarpus strobiliformis, on the other hand, share so many important characters that they could well be considered cogeneric. Both seed structure and the rudimentary grooves on the tubercles suggest that their affinities may lie with certain coryphanthas or mammillarias rather than with Ariocarpus and Epithelantha.
HISTOLOGICAL AND HISTOCHEMICAL CHANGES IN DEVELOPING AND RIPENING PEACHES. I. THE CATECHOL TANNINS
Authors: Reeve R. M.
Published: January 2018

Reeve, R. M. (U.S.D.A., Albany, California.) Histological and histochemical changes in developing and ripening peaches. I. The catechol tannins. Amer. Jour. Bot. 46(3) : 210‐217. Illus. 1959.—Selective histochemical tests for catechol derivatives revealed marked changes in tannin contents during the development and ripening of peaches. The principal test used was a nitroso reaction found to be colorimetrically selective for catechol and derivatives such as chlorogenic acid. Intensities of color produced by this test were photometrically measured. Increases in catechol derivatives, so indicated in situ, were associated with early maturation and lignification of the endocarp sclereids and particularly with cessation of cell divisions and early cell enlargement of the mesocarp parenchyma. Characteristic progressive localizations of tannins in patches of enlarging mesocarp parenchyma cells, as revealed by staining with iron salts as well as by the nitroso reaction, were observed in green fruits approaching maturity. The insoluble tannin color complexes produced by these tests remained coarsely granular and intense in green fruit. Upon ripening of the fruit color intensity produced by the nitroso reaction decreased and the insoluble tannin complexes were more finely divided. The association of phenols with cellular differentiation, lignification and suberization are briefly discussed.
VARIABILITY OF ACCESSORY CHROMOSOMES IN NATIVE POPULATIONS OF ALLIUM CERNUUM
Authors: Grun Paul
Published: January 2018

Grun, Paul. (Penn. State U., University Park.) Variability of accessory chromosomes in native populations of Allium cernuum. Amer. Jour. Bot. 46(3) : 218‐224. Illus. 1959.—Small euchromatic accessory chromosomes, which lack visible constrictions, have become established in native populations of nodding onion, Allium cernuum Roth. Variant types, including large accessories, and a form having a visible metacentric constriction, also occur, although more locally restricted in distribution. The accessories show a strong tendency towards non‐disjunction in mitotic divisions, resulting in a variability of number in different cells within and between root tips and in different microsporocytes of each plant. The metacentric chromosome undergoes a normal disjunction. Accessories are not paired at first metaphase of meiosis, and drift to poles at random during first anaphase, a few being lost as micronuclei. During second anaphase they go through the normal equational division. In spite of this mitotic and meiotic irregularity, plants of 11 of 14 separate populations collected in Pennsylvania and West Virginia contained accessories in up to a maximum of 50% of the individuals in the population.
DEVELOPMENT AND CYTOLOGY OF THE ENDOBIOTIC PHASE OF PHYSODERMA PULPOSUM
Authors: Lingappa Yamuna
Published: January 2018

Lingappa, Yamuna. (U. Michigan, Ann Arbor.) Development and cytology of the endobiotic phase of Physoderma pulposum. Amer. Jour. Bot. 46(4): 233–240. Illus. 1959.—The contents of the zygotes of Physoderma pulposum pass into the epidermal cells of the host and become incipient primary turbinate organs. The latter develop into resting sporangia in 3 different ways: (1) Occasionally, they may become thick walled as sporangia in their entirety. Such monocentric development of the endobiotic thalli is described for the first time in Physoderma; (2) usually, however, the contents of primary turbinate organs undergo centripetal cleavage; or (3) their contents may be cleaved tangentially. As a result, several uni‐ or multinucleate segments are formed which give rise to tenuous hyphae. The swollen distal end of each tenuous hypha develops into a secondary turbinate organ which in turn gives rise to hyphae and tertiary turbinate organs. Thus, the polycentric organization of the rhizomycelium is maintained. During this process, buds, which develop in the axils of the apical tufts of haustoria of turbinate organs, enlarge into resting sporangia. Nuclear divisions in turbinate organs and of resting sporangial initials are mitotic, and 4 chromosomes are evident on the equator of the intranuclear spindles. As the resting sporangia are inoperculate, the endosporangia protrude through irregular openings in the exospores.
HISTOLOGICAL AND HISTOCHEMICAL CHANGES IN DEVELOPING AND RIPENING PEACHES. II. THE CELL WALLS AND PECTINS
Authors: Reeve R. M.
Published: January 2018

Reeve, R. M. (U.S.D.A., Albany, California.) Histological and histochemical changes in developing and ripening peaches. II. The cell walls and pectins. Amer. Jour. Bot. 46(4): 241–247. Illus. 1959.—Histological and histochemical observations on developing and ripening clingstone and freestone peaches have revealed that, after cell divisions have ceased in the mesocarp, cell wall thickening and cell enlargement in the mesocarp parenchyma increase until the fruit is nearly full cell size. The cell walls then decrease in thickness as the fruit ripens and softens. Degree of methyl esterification of the pectic substances, as estimated histochemically, remains at about 75–80% in immature fruits during their cell‐enlargement phase of growth. Percent of methyl esterification apparently is much lower, or amounts of esterified pectates are very low during the meristematic phases of fruit growth. Just prior to ripening, degree of esterification increases and approaches 100% in hard, ripe fruit at about the same time that the parenchyma cell walls exhibit their greatest thickness or degree of hydration. The degree of esterification of the pectic substances then rapidly decreases and the cell walls become appreciably thinner as the ripening fruit softens. Further relation of these changes in wall thickness, in degree of esterification of the pectins, and in other cell wall carbohydrates to the textural qualities of ripening fruits is discussed. Interpretations concerning cell wall plasticity, cell growth and relation between auxin and changes in pectins also are presented.
MORPHOLOGICAL AND ONTOGENETIC STUDIES ON TORREYA CALIFORNICA. II. DEVELOPMENT OF THE MEGASPORANGIATE SHOOT PRIOR TO POLLINATION
Authors: Kemp Margaret
Published: January 2018

Kemp, Mahgaret. (Smith Coll., Northampton, Mass.) Morphological and ontogenetic studies on Torreya californica. II. Development of the megasporangiate shoot prior to pollination. Amer. Jour. Bot. 46(4): 249–261. Illus. 1959.—The development of the megasporangiate of Torreya californica during the first part of its maturation cycle of 26 months is described in detail. This first developmental period extends from the initiation stage in late July of one year through pollination of the young ovules in April of the following spring. At the end of this period, the reproductive shoot is a loosely organized, compound, determinate structure. It consists of a short primary axis which originated in the axil of one of the last formed bud scales or one of the first formed foliage leaves of the vegetative bud. This primary axis bears only 2 lateral and oppositely placed prophylls which stand at right angles to the subtending structure. In the axil of each prophyll is a short secondary axis which bears 2 successive pseudodecussate pairs of subopposite, sterile, scale‐like perianth segments below a solitary, erect, terminal ovule. The integument of the ovule originates as a single lateral primordium, but its margins quickly merge and at pollination time it is a tubular envelope free from the nucellus. The nucellus, which is massive and contains a single deeply imbedded megasporocyte, terminates the secondary axis. Histogenetically, both primary and secondary axis systems of the megasporangiate shoot resemble a vegetative dwarf shoot. They both originate as axillary mounds of uniformly meristematic cells, whose apices soon exhibit a zonal pattern comparable to that of the apex of the vegetative shoot of the same species. The determinate nature of the primary axis is caused by cell senescence in its apex. The prophylls of the primary axis and the perianth segments of the secondary axes are comparable to bud scales of the vegetative bud in their arrangement, their origin from subsurface layers, the presence of apical and subapical initials which produce their first vertical growth, a basal intercalary meristem which completes their elongation, and marginal initials which produce a slender wing to the lamina of each type of cataphyll. At maturity all 3 types of cataphylls are basically similar in their histology. The apex of each secondary axis, at the initiation of the integument, shows an altered cellular pattern which rapidly becomes organized into a conspicuous fanshaped coaxial system as the central portion develops directly into the massive, cauline nucellus. This coaxial apical configuration differs markedly from the zonal pattern of the vegetative shoot apex and also from the similar zonal pattern in the apex of the primary axis of the megasporangiate shoot and its secondary axes during an earlier period of indeterminate growth.
MORPHOLOGY OF HUMULUS LUPULUS. II. SECONDARY GROWTH IN THE ROOT AND SEEDLING VASCULARIZATION
Authors: Miller Robert H.
Published: January 2018

Miller, Robert H. (U. Nevada, Reno.) Morphology of Humulus luppulus. II. Secondary growth in the root and seedling vascularization. Amer. Jour. Bot. 46(4): 269–277. Illus. 1959.—In the primary state the roots of Humulus lupulus L. have a diarch xylem plate with 2 strands of primary phloem lying on either side of the primary xylem. Secondary histogenesis is described for the primary root. Fibrous and fleshy storage roots are developed by the hop plant and their respective developmental and anatomical structures are described. Lateral roots are initiated in the pericycle opposite the protoxylem poles. The architecture of these secondary roots is similar to that of the primary root. The seedling develops a fleshy storage organ through secondary growth of the primary root and the hypocotyl. The hypocotyl eventually resembles a fleshy taproot throughout most of its extent. The vascular cambium differentiates large amounts of parenchymatous tissues. A relatively smaller amount of tracheary tissue is formed. The secondary phloem comprises a high percentage of phloem parenchyma and ray cells containing numerous large starch grains, and constitutes the larger portion of the fleshy storage root. Numerous thick‐walled lignified fibers occur throughout the secondary vascular tissues. Resin and tannin cells are abundantly distributed. A phellogen is differentiated from the pericycle and develops a persistent periderm on the outer surface of the fleshy storage organ. A relatively short transition region occurs in the upper part of the hypocotyl. The transition takes place from a radially alternate arrangement of the vascular tissues in the root to a collateral arrangement in the cotyledons.
LITOSTROMA, A NEW GENUS OF PROBLEMATICAL ALGAE FROM THE PENNSYLVANIAN OF OKLAHOMA
Authors: Mamay Sergius H.
Published: January 2018

Mamay, Sergius H. (U. S. Geological Survey, Washington, D. C.) Litostroma, a new genus of problematical algae from the Pennsylvanian of Oklahoma. Amer. Jour. Bot. 46(4): 283–292. Illus. 1959.—Litostroma oklahomense, gen. et sp. nov. is described on the basis of fossil plant material found in a Pennsylvanian marine limestone from the vicinity of McAlester, Oklahoma. Litostroma is a simple plant consisting of a small, irregularly shaped thallus 1 cell thick. Some thalli have small perforations and filament‐like marginal outgrowths. The reproductive organs are not known. A marine fauna is intimately associated with Litostroma, and includes epiphytic Foraminifera preserved in actual growth positions on surfaces of the plants. The evidence indicates a marine habitat for Litostroma and, accordingly, algal affinity. Without information bearing on its reproductive organs or pigmentation, however, Litostroma cannot with assurance be assigned to any known group of algae. It possibly represents a group of green, brown, or even red algae.
THE CHEMICAL COMPOSITION OF THE HYPHAL WALLS OF THE FUNGUS ALLOMYCES
Authors: Aronson Jerome M. , Machlis Leonard
Published: January 2018

Aronson, Jerome M., and Leonard Machlis. (U. California, Berkeley.) The chemical composition of the hyphal walls of the fungus Allomyees. Amer. Jour. Bot. 46(4): 292–300. Illus. 1959.—The hyphal walls of Allomyces macrogynus were isloated by both alkaline digestion methods and by sonic oscillation. Both types of preparations showed the walls to consist of chitin, glucan, and ash. In addition, the mechanically isolated walls contained a protein fraction, the properties and significance of which were not determined. Hemicellulose‐type polysaccharides, pectic substances, ether soluble lipids, and constituents giving rise to 3–0‐α‐earboxyethyl hexosamine were not found to be present in the walls. The walls of plants grown for 60–70 hr. under the prescribed conditions contain approximately 60% chitin, 15% glucan, 10% ash, and 10% protein intimately associated with the walls. The percentage of wall material in a mycelium, as well as the percentage of chitin in the walls, increases with the chronological age of the mycelium. These percentages were not, however, affected by variations in the composition of the nutrient medium. The chitin in the walls could be hydrolyzed in the presence of chitinase; lysozyme, however, had no detectable effect on the walls.
GLANDULAR STRUCTURES OF HOLOCARPHA AND THEIR ONTOGENY
Authors: Carlquist Sherwin
Published: January 2018

Carlquist, Sherwin. (Rancho Santa Ana Botanic Garden, Claremont, California.) Glandular structures of Holocarpha and their ontogeny. Amer. Jour. Bot. 46(4): 300–308. Illus. 1959.—Two types of advanced glandular structures occur in the 4 species of the genus Holocarpha. Sessile disk‐shaped glands occur at the tips of upper leaves and of involucral and receptacular bracts. Unlike all other glandular structures of Madinae which have been investigated, these originate from several protodermal initials rather than a single one. These glands, however, represent modifications of a glandular trichome. The other type of glandular structure, termed hollow‐stalked trichome here, occurs on the outer surface of involucral and receptacular bracts. These trichomes originate from a single cell but differ from others in the formation of a hollow stalk, the wall of which is one cell in thickness. Mesophyll of the bract, often with an included vascular bundle, is present as an intrusion into the base of the hollow stalk. Corresponding to the advanced nature of the glandular structures, the leaves show specializations in the “inrolling” of margins. Upper leaves have a cylindrical organization of vascular tissue, whereas basal leaves are “normal” and leaves of the main stem are intermediate. The species of Holocarpha differ in certain details of leaf anatomy and structure of hollow‐stalked trichomes. The systematic distribution of these is given. The essential unity of the various glandular structures of Madinae is discussed both in terms of mature structure and ontogeny, and the steps in the evolution of these are suggested.