Cossatot leafcup, Polymnia cossatotensis [Asteraceae], is an endemic of the Interior Highlands region of Arkansas. Polymnia cossatotensis was discovered in 1988 and is known only from four sites in Polk and Montgomery Counties of western Arkansas. Because of its extreme rarity, P. cossatotensis is listed as G1 and is considered critically imperiled. We visited Polymnia cossatotensis populations from 8 August to 11 August 2006 where we recorded general site characteristics and associated species, collected soil samples, and established population sizes using line transects. The estimated number of individuals for the species is 33,765 plants of which 33,719 are located in just two of the populations. Our findings emphasize the conservation value of these two largest populations.

Solidago verna M. A. Curtis ex Torrey & A. Gray (spring-flowering goldenrod) [Asteraceae] is threatened in North Carolina, a species of federal concern, endemic to fire– adapted longleaf pine flatwoods in the Carolinas, and is in the Center for Plant Conservation's National Collection of Endangered Plants. Highway construction threatens the largest known population of S. verna. We conducted a transplant study to provide information for the plan being developed to mitigate for the impact of the highway. Plants of the threatened population were transplanted into study plots on seven Coastal Plain soils varying in wetness. Half of the plots on each soil were controls with unclipped neighbor vegetation; the others were experimental plots with clipped vegetation. Soil was the most important factor affecting transplant survival. Survival was lowest on soils that experienced ponding or flooding. Neighbor vegetation clipping tended to improve survival, with the greatest improvement on soils of intermediate wetness. Soil wetness and vegetation treatment (clipped or unclipped) accounted for only 16% of transplant growth variation. We recommend establishing a mitigation transplant population on moderately well drained or somewhat poorly drained soils such as Craven or Lenoir. Managing the transplant population could utilize mowing during those periods when fire is not practical.

Historically, fire and the southern pine beetle (Dendroctonus frontalis) have interacted in a manner that maintains the stability of pine-dominated forests in the southern Appalachians. Fire suppression has recently been implicated in the disruption of the integrity of these forests and their shift toward hardwood dominance. This study examined the influences of fire and southern pine beetle infestation on stand structure and resin flow of pines in pine-dominated forests in the Linville Gorge Wilderness of North Carolina. Resin flow in most pine species increases in response to various types of wounding and is a pine tree's primary defense against insect pathogens. Pine-dominated stands in this study decreased in both basal area and density after exposure to fire and/or southern pine beetle infestation. Decreases in basal area and density of Pinus pungens were strongly associated with infestation, while decreases in Pinus rigida were influenced primarily by exposure to fire. Resin flow was substantially higher in trees that were exposed to fire, but not infested, than in trees experiencing any other combination of fire exposure and infestation (including trees that were neither exposed to fire nor infested). This elevated resin flow was still present 18 mo after burning. Since resin flow is the primary means of host defense against southern pine beetle, it is suspected that fire could confer an acquired resistance to future southern pine beetle infestations through elevated resin flow.

Blackland prairies are found in two regions of Mississippi and Alabama, the Black Belt and the Jackson Prairie Belt. As the vegetation of remnant prairies in these belts has received limited attention, we collected and identified the grasses and forbs from 19 sites in Mississippi and western Alabama over a year. A total of 196 species were collected, including 168 native species. When compared with prairie species lists for these regions from the early 20th century, our results suggest that 18 species present then may now be rare or absent. Habitat data for these species indicate that most favor more mesic or sandier soils. Their apparent absence implies that existing prairies are a subset of historic prairies that were not useful for agriculture because of drier and/or more clayey soils. To preserve the biodiversity of this ecosystem, conservation efforts should include more mesic or sandy sites, including prairie-forest ecotones.

The 15,410 ha Tallgrass Prairie Preserve (Osage County, Oklahoma), managed by The Nature Conservancy, consists of a variety of grassland, forested, wetland, and disturbed habitats. 1,612 specimens of vascular plants collected between 1992 and 2007 were examined to obtain a vouchered flora of the preserve. The known flora consists of 763 species in 411 genera and 109 families. 12.1% of the species are not native to North America.

Allozyme and RAPD analyses conducted on Cypripedium reginae populations from previously glaciated and unglaciated sites indicated low species- and population-level diversity and moderate population differentiation. Low species-level variation may be attributed to founder effect during Pleistocene range shifts, genetic bottlenecks in a relatively small refugial southern range, and genetic drift in small and isolated southern populations during glacial advance. Populations from previously glaciated sites harbored higher genetic diversity than populations from unglaciated sites. This geographic pattern of population genetic structure is highly irregular among organisms with disjunct ranges where most studies have revealed higher levels of genetic diversity in unglaciated refugial populations. We attribute this pattern in C. reginae to the presence of abundant open wetland habitat near advancing glaciers that served as refugia for diverse northern populations that were well positioned to recolonize open wetland habitat after final recession of Pleistocene glaciers.