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Rudbeckia auriculata is a rare wetland-associated species endemic to three southeastern states: Alabama, Florida, and Georgia. This study includes eight censuses of flowering individuals of the species during the ten-year period from 1992 to 2002. Although the number of known populations has increased during this time, the total number of flowering stems has remained relatively constant. Population size ranged from a single flowering stem to populations with over 1,000 flowering stems. Information on soils and associated species of vascular plants was collected at 20 of the 32 known sites during 1999, 2000, and 2001. Typical sites for the plant are located on wet soils along roadsides, power line right-of-ways or other disturbed sites. Associated species are those characteristic of disturbed open wetland sites. Although some large colonies of R. auriculata still exist, only two populations, both in the northern portion of the species' range, have been protected.
Monotropa uniflora has a disjunct geographical distribution. One part of the distribution encompasses much of North America, a second part extends throughout Central America and a third part runs through eastern Asia. The present study, based on large ribosomal subunit (26S) rRNA gene sequence data, suggests that M. uniflora from Asia, North America, and Central America are each molecularly diverged and phylogenetically distinct.
The Rappahannock River is a major river system across north central Virginia prior to entering the Chesapeake Bay. In contrast, the Pamunkey River is smaller in size and joins the Mattoponi River to form the York River, which flows parallel to the Rappahannock before it also flows into Chesapeake Bay. A unique mixing area for both flora and environmental conditions exists in the tidal freshwater-oligohaline region of both rivers. This is a dynamic mixing section where freshwater and estuarine species are subject to the interaction of river flow and daily tidal rhythms. The phytoplankton composition in this region of the two rivers was identified over a 13.5-year period (July 1986–December 1999). The results indicated freshwater and estuarine populations forming a diverse assemblage of 268 taxa, with diatoms, chlorophytes, and cyanoprokaryotes the dominant flora. Phytoplankton in this region were predominantly freshwater taxa (e.g., >70%), with a diverse diatom assemblage representing >90% of the estuarine flora at these sites.
This paper reports the results of an inventory of the vascular plants at the Red Slough and Grassy Slough Wildlife Management Areas in southeastern Oklahoma. A total of 426 taxa of vascular plants in 269 genera and 106 families was collected. The most species were collected from the families Asteraceae (53), Poaceae (42), Cyperaceae (31), and Fabaceae (27). Ninety-nine species were annuals or biennials, and 328 perennials. Ninety-three species of woody plants were present. Twenty-eight species not native to North America were collected representing 6.6% of the flora. Thirty species tracked by the Oklahoma Natural Heritage Inventory were found. The first occurrence in Oklahoma of Anoda cristata, Malvaceae, is reported in this study.
In eastern forests, openings dominated by grasses, forbs, or shrubs are areas of conservation concern because they typically contain endemic, threatened, and rare plants. Understanding the ecology and mechanisms of tree encroachment would be valuable for conservation managers and would add to a substantial body of literature on forest openings. In this study, we worked in grass-dominated forest openings on Buffalo Mountain, Virginia using a method that combined dendrochronology and belt transects to assess tree encroachment. We discovered both stable ecotones and areas where trees were invading the formerly grass-dominated openings. Both gradual and episodic patterns of tree encroachment were identified; however, successful tree establishment always initiated from the edge of the forest-grass ecotone and progressed towards the center of the opening rather than occurring across the entire forest opening. This spatial pattern of recruitment implies that successional facilitation is necessary for tree encroachment in forested openings at Buffalo Mountain.
Daughmer Savannah, Crawford County, Ohio is the largest and best preserved remnant of the unplowed, deep soil prairies and savannahs that were present at the easternmost extension of the Prairie Peninsula prior to European settlement. Repeated surveys of plant species composition over three years were combined with quantitative community sampling of plants and soils during 1999 to produce a comprehensive ecological and botanical analysis of this 16 ha site. A total of 166 species representing 109 genera from 48 plant families were recorded. Approximately 30% of the graminoids and 20% of the forbs were species with strong prairie affinities. Three sedges listed by the Ohio Department of Natural Resources as threatened or endangered (Carex atherodes, C. bicknelli and C. sartwellii) were present. Detrended Correspondence Analysis identified six major community types within Daughmer Savannah: oak savannah dominated by Quercus macrocarpa, mesic prairie dominated by Andropogon gerardii, Schizachyrium scoparium and other prairie grasses and forbs, wet prairie dominated by Spartina pectinata or Calamagrostis canadensis depending on the area, sedge meadow dominated by a mixture of Carex atherodes and C. lacustris, bluejoint swales dominated by Calamagrostis canadensis and Muhlenbergia mexicana, and prairie pothole marsh dominated by emergent aquatic plants. Species composition and community delineations were similar to those developed for Wisconsin by Curtis in the 1950's. This site should be used as a model for restoration of diverse prairie landscapes in the region.