Showing papers in "Taxon in 1982"

Mosses of Eastern North America

Abstract: IntroductionVOLUME 1Class SphagnopsidaClass AndreaeopsidaBryopsidaSubclass ArchidiidaeSubclass BryidaeOrder FissidentalesOrder ByroxiphialesOrder SchistostegalesOrder DicranalesOrder PottialesOrder GrimmialesOrder FunarialesOrder BryalesVOLUME 2Order IsobryalesOrder HookerialesOrder HypnobryalesSubclass BuxbaumiidaeSubclass TetraphididaeSubclass PolytrichidaeConspectus of TaxaGlossaryBibliographyIndex

Biology of Plants

Abstract: BOTANY: AN INTRODUCTION - PART 1: THE BIOLOGY OF THE PLANT CELL - The Molecular Composition of Plant Cells - The Plant Cell and the Cell Cycle - The Movement of Substances Into and Out of Cells - PART 2: Energetics - The Flow of Energy - Respiration - Photosynthesis, Light, and Life - PART 3: GENETICS AND EVOLUTION - Sexual Reproduction and Heredity - The Chemistry of Heredity and Gene Expression - Recombinant DNA Technology, Plant Biotechnology, and Genomics - The Process of Evolution - PART 4: DIVERSITY - Systematics: The Science of Biological Diversity - Prokaryotes and Viruses - Fungi - Algae and Heterotrophic Protists - Bryophytes - Seedless Vascular Plants - Gymnosperms - Introduction to the Angiosperms - Evolution of the Angiosperms - The Human Prospect - PART 5: THE ANGIOSPERM PLANT BODY: STRUCTURE AND DEVELOPMENT - Early Development of the Plant Body - Cells and Tissues of the Plant Body - The Root: Structure and Development - The Shoot: Primary Structure and Development - Secondary Growth in Stems - PART 6: PHYSIOLOGY OF SEED PLANTS - Regulating Growth and Development: The Plant Hormones - External Factors and Plant Growth - Plant Nutrition and Soils - The Movement of Water and Solutes in Plants - ON THE WEB - PART 7: ECOLOGY - The Dynamics of Communities and Ecosystems - Global Ecology

Systematics of gramineae a cluster analysis study

Abstract: scopic characters and 3) on combination of the two. Neither the morphological nor the microscopic characters alone resulted in an appreciable grouping of the genera. The microscopic characters, however, produced clusters that better approach the present subfamilial classifications. Combination of the two subsets of characters resulted in eight clusters representing the modern subfamilies Pooideae, Oryzoideae, Panicoideae, Eragrostoideae, Arundinoideae, Centostecoideae, Bambusoideae and a new potential subfamily (Nardoideae) that included Lygeum, Nardus and Diarrhena. The tribal constituents of these subfamilies are discussed in detail. It has been concluded that classification of grasses seems more natural at the level of the subfamily than tribe.

Contributions to the ecology of halophytes.

Abstract: One: Biology and Biogeography of Halophytic Species and Salinity Controlled Ecosystems.- Wet halophytic ecosystems.- 1. Ecology of the halophytic vegetation of Egypt.- 2. Estuarine ecosystem of India.- 3. The biogeography of mangroves.- Dry halophytic ecosystems.- 4. Survey and adaptive biology of halophytes in western Rajasthan, India.- 5. Biology of Atriplex.- Two: Ecological and Ecophysiological Problems.- 1. Mangrove species zonation: why?.- 2. Distribution and environmental control of productivity and growth form of Spartina alterniflora (Loisel.).- 3. Germination ecology of halophytes.- 4. Aspects of salinity and water relations of Australian chenopods.- 5. Senescence in mangroves.- 6. Ecophysiological aspects of some tropical salt marsh halophytes.- 7. Adaptation of plants to saline environments: salt excretion and glandular structure.- 8. The role of bladders for salt removal in some Chenopodiaceae (mainly Atriplex species).- Three: Potentialities and Uses of Halophytic Species and Ecosystems.- 1. Halophytes and human welfare.- Plant index.

Structural and evolutionary aspects of the flagellar apparatus in green algae and land plants

Abstract: Ultrastructural features of the flagellar apparatus in green algae and land plants seem to be of considerable phylogenetic significance. Based on functional considerations details of the flagellar apparatus can be used to construct tentative lines of evolution within the green algae. An 'ancestral" asymmetric zooflagellate possibly gave rise to a green unicell after a primary endosymbiotic event involving a green prokaryote. During the transition from phagotrophic to phototrophic nutrition in most green algae (the Chlorophyceae and Ulvaphyceae sensu Stewart & Mattox and most Prasinophyceae sensu Christensen) the original asymmetric flagellar apparatus was transformed into a 180? rotational symmetric flagellar apparatus with 4 flagella and a flagellar root system of the X-2-X-2-type. Most significant in this transition was presumably the evolution of the phototactic apparatus and of an apical flagellar groove. In the Charophyceae sensu Stewart & Mattox (including those green algae related to the ancestry of the archegoniate land plants) the early transition towards a terrestrial life, lack of an eyespot apparatus and development of a special type of oogamy possibly led to the evolution of the unilateral flagellar root in these organisms. It is suggested that the evolution of the unilateral MLS-root in the Charophyceae sensu Stewart & Mattox can be traced back to an "ancestral green flagellate" before the evolution of the typical X-2-X-2 flagellar root system. A tentative evolutionary scheme of the green algae mainly based on motile cell structure and mitotic and cytokinetic mechanisms is presented.

The classification of Poaceae subfamily Pooideae

Abstract: Following a review of previous classifications, a revised scheme is presented for the 155 genera of Pooideae, derived via numerical analyses of original and compiled morphological and anatomical data and consideration of additional evidence. The subfamily is divided into two newly described supertribes, Poanae and Triticanae. These are further subdivided into the following tribes, all fully described: Poeae, Seslerieae, Meliceae, Aveneae and Agrostideae (in Poanae) and Triticeae, Bromeae and Brachypodieae (in Triticanae). The Aveneae are more narrowly circumscribed than is usual. The data employed in the numerical analyses are available, on microfiche, as full English descriptions.

The Useful Plants of Central America

Abstract: Plants used by man in Central America for food, including vegetables and fruits, beverages, spices, medicines and drugs, fibers, tans and dyes, timber, rubber and ornamentals are presented in family order with common names in a range of languages, descriptions and lists of uses. The index is published separately as Ceiba 24, 3/4 . -- AATA

Descriptors used to indicate abundance and frequency in ecology and systematics

Abstract: It is an arresting fact that in the year of our Lord 1981 there still is no general agreement in ecology, systematics, and comparative anatomy/morphology as to the application of such widely used terms as 'usually,' 'many,' 'often,' 'rarely,' etc. While such descriptors have rather specific meanings, as consultation of any dictionary will show, there is no standardization with regard to equivalency of these and other terms. It is thus easy to find in the literature considerable variance in their usage. For example, Myrtaceae, with approximately 149 genera and 3676 species (Schmid, 1980b), are variously said to have leaves 'opposite' (0+3 taxonomic accounts), 'usually opposite' (1+1), 'mostly opposite' (0+1), 'very often opposite' (0+ 1), 'usually opposite, but alternate in many taxa' (0+ 1), 'usually opposite, rarely alternate' (0+1), 'mostly opposite, rarely alternate' (0+3), 'often opposite, rarely alternate' (1+0), 'opposite, less frequently alternate' (1+0), 'opposite, rarely alternate' (3+8), and 'opposite or alternate' (1+3). This is appreciable descriptive variability, even if one allows for the fact that older taxonomic accounts (indicated by the numbers before the plus signs in the parentheses) include in Myrtaceae the strictly alternate-leaved Lecythidaceae sensu lato (including Asteranthaceae, Barringtoniaceae, Foetidaceae, and Napoleonaeaceae) with some 24 genera and 402 species (number of taxa from Airy Shaw, 1973). Actually, after an extensive analysis of the literature of Myrtaceae (see Briggs and Johnson, 1979 and Schmid, 1980b), I estimated that approximately 78% of the species of Myrtaceae (excluding Lecythidaceae) have opposite leaves and 22% have alternate leaves and thus characterized the family as having 'leaves usually opposite (to whorled), occasionally alternate' (Schmid, 1980b, Table 3 therein). Although frequent attempts (e.g., Lathrop and Thorne, 1978) have been made to define accurately descriptors such as those in the preceding paragraph, there seems to have been no detailed effort to assign precision, on an approximate quantitative/ percentage basis, to essentially qualitative terms such as the aforecited. Table 1 summarizes my percentage criteria for various descriptors. These criteria were derived from four studies (Schmid, 1980a, b, 1981a, b), in particular a survey of the frequency of expression of 87 vegetative and reproductive morphological/anatomical characters in Myrtaceae and Lythraceae and 23 characters in the four subfamilies of Myrtaceae (Schmid, 1980b, Tables 3 and 4 therein). The following discussion gives my rationale for these criteria. The actual descriptive terms used in Table 1 are common in the literature. I selected them because in most cases they seem to be not only the most commonly used terms, but also the shortest ones. 'Occasionally' was chosen over 'sometimes' because the former easily abbreviates to 'occ.' Other more or less equivalent descriptors are given in note 1 to Table 1. The use of 'very' is generally disparaged in style manuals, but this qualifier seems justifiable for 'rarely,' 'occasionally,' and 'often' in Table 1. For example, in Lythraceae with ca 29 genera and 590 species (Schmid, 1980b) axile placentation occurs in all species but two, namely Ammannia microcarpa (=Cryptotheca dichotoma) (many literature reports) and Alzatea verticillata (Lourteig, 1965, and my observa-

Recent changes in the flora of the juan fernandez islands, chile

Abstract: During the recent Universidad de Concepci6n-Ohio State University expeditions to the Juan Fernandez Islands, observations were made concerning recent changes in the composition and extent of the native flora. In comparison with the data of Skottsberg from 1916-17, many of the endemic species have become much rarer, and some perhaps extinct. Several especially aggressive introduced species, e.g., Acaena argentea, Aristotelia chilensis, and Rubus ulmifolius, continue to invade and replace the native vegetation. Increasing areas of dry habitats and increasing proportions of xeromorphic or lithophilic plants now characterize the total vegetation. The total area of native vegetation is now restricted to the central ridges and cliffs. The major causes for the floristic degradation appear to be the introduced animals which have overgrazed and trampled the plants as well as compacted the soil. This has lead to erosion and further loss or degradation of the plant cover.

Three taxa constitute the sexes of a single dioecious species of solanum

Abstract: Summary Solanum appendiculatum H. et B. ex Dun., S. connatum Corr., and S. inscendens Rydb. constitute the single dioecious species, S. appendiculatum. These taxa are fully intercompatible and morphologically very similar. They were distinguished by differences in style length and in the degree of filament fusion; however, the first character is associated with the gender of the plants, and the latter shows variability and inheritance patterns not associated with species boundaries.

The origin of land plants: a paleobotanical perspective1

Abstract: Summary The discovery of numerous fossil plants in recent years, together with the application of new techniques directed at understanding the total biology of the organism, has resulted in the modification of some ideas pertaining to the origin of land plants. Several of these lines of evidence strongly suggest the presence of a diverse terrestrial flora significantly earlier than the Upper Silurian bench mark currently used for the first appearance of plants with vascular tissue. Few would disagree that the invasion of the land by aquatic plants was one of the major evolutionary events. However, when this migration took place, what groups of plants were involved, whether the land was invaded once or many times, and what factors initiated the movement to land, continue to persist as fundamental questions that are of interest to scholars in many disciplines. Biologists have speculated for a long time that land plants have their origins with some green algal group. This assumption has been based upon cell wall chemistry, quantity and quality of pigments, type of stored food, and method of reproduction. In recent years there has been considerable activity in identifying what specific groups might have been involved in land plant ancestory. This has come about through the combined efforts of numerous workers (e.g., Pickett-Heaps, 1976; Stewart and Mattox, 1975, 1978), and has involved an analysis of the biochemistry, and especially mitotic and cytokinetic ultrastructure of selected members of the green algae (Chlorophycophyta). For example, Stewart and Mattox (1975) have separated the advanced genera within the Chlorophycophyta into two probable evolutionary lines that share a common ancestor with some uniflagellate, scaly unicellular alga (Mattox and Stewart, 1977). In one of these lines (Chlorophyceae) all of the members possess a collapsing interzonal spindle at telophase associated with the formation of a phycoplast. The motile cells have anteriorly attached flagella that are anchored to four narrow microtubular roots. All produce glycolate dehydrogenase. The second line, and the one that is believed to share features with land plants, is characterized by taxa that possess glycolate oxidase and have a persistent interzonal spindle that may develop into a phragmoplast. The motile cells in these forms possess laterally attached flagella that are associated with a single broad band of closely adjacent microtubules. Included within this line (Charophyceae) as interpreted by Stewart and Mattox (1975) are four orders: Klebsormidiales, Zygnematales, Coleochaetales, and Charales. Among these it is the Charales and Coleochaetales that are regarded as the most highly evolved green algae, and that are believed to be related to the land plants.

Tulips : taxonomy, morphology, cytology, phytogeography and physiology

Abstract: This text is a taxonomic source for the genus with information on the botanic species in the genus centres.

Some medicinal plants of the hehe (southern highlands province, tanzania)

Abstract: Our search for plants that are used by primitive people in ways that might indicate an effect on the central nervous system led us to East Africa in 1963. The choice of a locality in which to collect is often fortuitous, in this case a contact with an anthropologist, one of a team from the University of California, Los Angeles, who returned from an extended stay in East Africa with a few plant specimens and a small collection of prepared medicines with local names. The former were mostly plants known to be useful and recorded in the literature, but the plant sources of the latter could not be identified from the native names. The best solution was to visit the original collection site and attempt to collect the plants from which the preparations had been made. We were fortunate in that the anthropologists were able to provide the names of an interpreter and the local medicine men. Our collecting areas were in the Southern Highlands Province in the vicinity of Iringa. The native vegetation is largely Brachystegia woodland, but the medicine men in this area have exploited the total environment, often travelling miles to get a particular plant. We were taken to a number of habitats, from pools along the Little Ruaha River, with a typical riverine vegetation, to thorn scrub on dry rocky hillsides, woodland of Brachystegia and Julbernardia, and open savanna dominated by Parinari. Because of the short time that we could spend in the field we concentrated our efforts on collecting plants that were used in the treatment of epilepsy and insanity, although occasionally we obtained specimens of plants used for other medicinal uses. Herbarium material of each plant was collected, along with material for pharmacological and chemical screening, and some information on methods of preparation of the medicines and dosages. In studying treatments for epilepsy and insanity there are special problems. The patient is often presumed to be bewitched by some supernatural power or by another person. The obvious cure is to thoroughly purge the patient of all foreign influences, and, consequently, medicines which produced violent reactions are assumed to be the most effective. Our collections are indicative of this belief. The plants we obtained contain violent purgatives and emetics, and some of the plants would produce death in overdose. These collections add a significant number of new plants and new uses to the record of medicinal plants. Of the fifty-two species collected, ten are not included in the extensive lists published by Watt and Breyer-Brandwijk (1962) and Kokwaro (1976). New medicinal uses are reported for thirty-one species. Of particular interest is the use of many of these plants in mixtures of two to eleven plants. Such mixtures complicate the pharmacological screening. The collections are listed alphabetically by family. Hehe common names, use and collection number are given. Voucher specimens are at EA and LA. The parenthetical capital letter indicates the treatment in which the plant was used. Following the species list a summary is given of the treatments used by the two informants. Treatments A-L were from an informant in a rural environment. He had