Plant Sciences Commons^™

Morphological Stasis Abd Molecular Divergence In The Intercontinental Disjunct Genus Datisca (Datiscaceae), Aaron Liston, Loren H. Rieseberg, Thomas S. Elias

Aliso: A Journal of Systematic and Floristic Botany

The genus Datisca comprises two species and has an intercontinentally disjunct distribution: D. cannabina is native to southwest and central Asia, whereas D. glomerata is distributed from northern California to northern Baja California. In 1975, Axelrod proposed a geohistorical scenario to account for such "Madrean-Tethyan links," suggesting that these disjunctions resulted from migration across the mid-Atlantic from the Paleogene up to the Neogene, approximately 23 to 65 m.y.a. The two species are quite similar in most phenotypic traits which have been studied to date. The major difference between the two involves their breeding system: D. cannabina is dioecious while D. …

Wood Anatomy Of Ascarina (Chloranthaceae) And The Tracheid-Vessel Element Transition, Sherwin Carlquist

Aliso: A Journal of Systematic and Floristic Botany

Quantitative and qualitative features are presented for 13 collections of 8 species of Ascarina. Wood anatomy is maximally primitive in most respects; moderate exception occurs in the imperforate tracheary elements, which range from tracheidlike (A. solmsiana) to fiber-tracheids (septate in two species). Perforation plates are scalariform, average more than 100 bars per plate, and have bordered bars. Even more significantly, portions of the primary walls in perforations characteristically fail to dissolve; these pit membrane portions range from nearly intact (much like the pit membranes in pits on end walls of tracheids of vesselless dicotyledons) to remnant strands …

Maine's Endangered And Threatened Plants, Maine State Planning Office

Maine Collection

Maine's Endangered and Threatened Plants

Executive Department, Maine State Planning Office, Critical Areas Program, 1990.

Flowering Plants: Nightshades To Mistletoe, Robert H. Mohlenbrock

Illustrated Flora of Illinois

This sixth volume of dicots contains three orders and eight families. The orders included are Solanales, Campanulales, and Santalales. Within the Solanales are the families Solanaceae, Convolvulaceae, Cuscutaceae, and Polemoniaceae. The Campanulales contain only the family Campanulaceae. The Santalales include the families Celastraceae, Santalaceae, and Viscaceae. As with each volume in this series Mohlenbrock includes a complete plant description, illustrations showing diagnostic features, distribution maps, and ecological notes.

Relative Effects Of Nutrient Enrichment And Grazing On Epiphyton-Macrophyte (Zostera Marina L.) Dynamics, Hilary A. Neckles

Dissertations, Theses, and Masters Projects

Dissolved nutrient concentrations and invertebrate grazing activity regulate epiphytic biomass. Because epiphyton may limit light and carbon at leaf surfaces and the consequent productivity of submerged macrophytes, factors which influence epiphytic biomass may indirectly affect macrophyte abundance. I measured the simultaneous effects of water column nutrients (ambient or 3x ambient concentrations of nitrogen and phosphorus) and grazing (presence or absence of epifaunal community) on epiphyton and macrophytes seasonally in eelgrass (Zostera marina L.) microcosms on lower Chesapeake Bay. Grazing was more important than nutrients in controlling accrual of total epiphytic biomass, although effects on epiphytic components varied; numbers of diatoms …

Vegetation Of Saratoga Landing Blackland Prairie, Thomas L. Foti

Journal of the Arkansas Academy of Science

Saratoga Landing Blackland Prairie is a 75-ha site owned by the U.S. Army Corps of Engineers and managed cooperatively with the Arkansas Natural Heritage Commission to protect its blackland prairie community and rare plant species. The site is a complex of prairies and forests, as interpreted from aerial photos and maps. It was substantially prairie at the time of settlement, and forest cover did not increase greatly until after 1951, apparently due to effective suppression of wildfires after that time. Plot sampling characterizes an individual prairie on the site as being dominated by a herbaceous canopy, but with a substantial …

Photosynthetic Competence Of An Endangered Shrub, Lindera Melissifolia, Robert D. Wright

Journal of the Arkansas Academy of Science

Net photosynthesis and water relations were investigated in situ for a population of Lindera melissifolia in northeast Arkansas. Photosynthetic light use efficiency was found to be characteristic of a shade plant. Response of photosynthesis to temperature and CO₂ was insensitive over ranges found during the growing season. High water use efficiency was demonstrated, but under typical conditions of low light this was marginally beneficial. In comparison -with competing understory plants, the species proved to be photosynthetically competent. The data are evaluated in terms of the survival potential of the species.

Fescues With Large Roots Are Drought Tolerant, H. A. Torbert, J. H. Edwards, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Consideration of root/soil interactions is essential in, adapting tall fescue (Festuca arundinacea Schreb.) to soil and climatic conditions of the Coastal Plain region of the southeast. Sandy soils of the region are very susceptible to the formation of hardpans. These compacted layers often restrict plant root development to the plow layer (0 to 6 in.) and prevent plant roots from reaching available moisture and nutrients in the subsoil horizons. Plants grown under these conditions are shallow rooted and will be subjected to water stress up to 50% of the time during the growing season. Although implements are available to penetrate …

Achene Microstructure In Eriophorum L. (Cyperaceae): Systematic Implications And Paleobotanical Applications, Gordon C. Tucker, Norton G. Miller

Faculty Research & Creative Activity

Silica bodies in the outer cells of the achene epidermis in 17 species of Eriophorum-and nine species of Scirpus, some of which have been placed in Eriophorum, were revealed by sonication and/or acetolysis and examined by scanning electron microscopy. A silica body consists of a basal platform, one or more large elevated protuberances, and sometimes smaller satellite protuberances. Individual species differ in the number of protuberances, the presence/absence of satellites, the texture of the platform, and the occurrence of nodules on the larger protuberances. These features, combined with achene shape and characteristics of the anticlinal walls of the epidermal cells …

Effects Of Lake Management On Chemical, Physical, And Phycological Characteristics Of A Hypereutrophic Reservoir, Kaye J. Surratt

Masters Theses

Lake Charleston is a 1.1 billion gallon capacity side channel reservoir which was constructed in 1982 as a public drinking water supply for the City of Charleston in Coles County, Illinois. Past studies of the lake indicated an increase in eutrophication and the capacity to support large algal populations. Recent lake management practices include copper sulfate applications as an algicide and aeration to reduce flavor and odor.

In order to assess present lake status and to evaluate the effectiveness of lake management practices, two lake sites were sampled on a weekly basis from May to October, 1989. Chemical, physical, and …

Flueggea Willd, W. John Hayden

Biology Faculty Publications

Shrubs to large trees with watery sap. Leaves simple, alternate, pinnately veined, stipulate. Flowers unisexual (and the plants dioecious or rarely monoecious), actinomorphic, in axillary clusters; sepals 4-7, imbricate; petals absent; nectary disk lobed or entire; stamens (3)4-7, alternate with the lobes of floral disk, staminodes absent in pistillate flowers; filaments distinct; ovary superior, on a hypogynous disk, (2)3(4)-carpellate, ovules 2 per cell, hemitropous, pistillode present in staminate flowers; styles distinct and 2-lobed or stigmas sessile. Fruit a capsule or baccate, indehiscent. Seeds 2 per cell. [Hayden, 1987; Sherff, 1939b]

The Vascular Flora Of Western Isle Of Wight County, Virginia, Gregory Michael Plunkett

Dissertations, Theses, and Masters Projects

No abstract provided.

Achene Microstructure In Eriophorum L. (Cyperaceae): Systematic Implications And Paleobotanical Applications, Gordon Tucker, Norton Miller

Faculty Research & Creative Activity

Silica bodies in the outer cells of the achene epidermis in 17 species of Eriophorum-and nine species of Scirpus, some of which have been placed in Eriophorum, were revealed by sonication and/or acetolysis and examined by scanning electron microscopy. A silica body consists of a basal platform, one or more large elevated protuberances, and sometimes smaller satellite protuberances. Individual species differ in the number of protuberances, the presence/absence of satellites, the texture of the platform, and the occurrence of nodules on the larger protuberances. These features, combined with achene shape and characteristics of the anticlinal walls of the epidermal cells …

Evaluation Of Seeding Rates Of Au Triumph And Endophyte-Infected Kentucky 31 Tall Fescue, Jeffrey F. Pedersen, D. M. Ball

Department of Agronomy and Horticulture: Faculty Publications

Increased difficulty in stand establishment of tall fescue (Festuca arundinacea Schreb.) has been reported by producers since the introduction of endophyte (Acremonium coenophialum Morgan Jones and Gams)-free tall fescue seed into the market place. This has encouraged the use of higher seeding rates for endophyte-free tall fescue without scientific basis. The objective of this study was to determine whether ‘AU Triumph’, and endophyte-free cultivar, and endophyte-infected ‘Kentucky 31’ differ in minimum seeding rates for successful establishment. Experiments were established at two locations in each of two years, using a randomized complete block with four replications. Soils at the two locations …

Heritability Of Root Characteristics Affecting Mineral Uptake In Tall Fescue, J. H. Edwards, Jeffrey F. Pedersen, R. C. Kingery

Department of Agronomy and Horticulture: Faculty Publications

Modification of plant roots can potentially increase the area. of adaptation of tall fescue (Festuca arundinacea Schreb.). Limited information is available on the heritability of root diameter and root volume in tall fescue. A greenhouse experiment was conducted with'50 random 'Kentucky 31' (Ky-31) tall fescue parents and their progeny grown in aerated nutrient solution during four separate time intervals. Measurements of root volume, root diameter, shoot Mg concentration, and shoot K/(Mg + Ca) ratio were made six weeks after clonal material was transplanted in nutrient solution. Heritability estimates for root volume, root diameter, shoot Mg concentration, and shoot K/(Mg …

A Review Of The Agronomic Characteristics Of Endophyte-Free And Endophyte-Infected Tall Fescue, Jeffrey F. Pedersen, G. D. Lacefield, D. M. Ball

Department of Agronomy and Horticulture: Faculty Publications

Agronomic differences between endophyte- (Acremonium coenophialum Morgan Jones and Gams) free and endophyte-infected tall fescue (Festuca arundinacea Schreb.) exist, and should be considered when implementing a management strategy. Although dry matter yield of tall fescue does not generally appear to be influenced by endophyte infection status, endophyte infection has been shown to improve seedling performance and survival, is associated with insect and nematode resistance, drought resistance, improved nitrogen assimilation, and higher seed set. Considering all biologically valuable characters of the endophyte-tall fescue relationship, survival of endophyte-infected tall fescue is probably better than that of endophyte-free tall fescue, especially in drought- …

Factors Related To The Occurrence Of Certain Prairie Graminoid Species In Black Hawk County, Iowa, Roadsides, Pauline Mary Drobney

Dissertations and Theses @ UNI

The native vegetation of Iowa was primarily tallgrass prairie and currently exists only in small isolated parcels, including some remnants occurring in roadsides. Roadside prairie remnants are important for historical, environmental, aesthetic, scientific, and economic reasons. Information about factors influencing the occurrance of roadside prairie vegetation could be useful to roadside vegetation managers in development of initial vegetation surveys and subsequent to restoration of roadside prairie vegetation.

This study was conducted to determine what factors most affected the percent coverage of prairie graminoids in roadsides; particularly soil moisture availability, drainage, soil disturbance, and availability of a prairie seed sources. Prairie …