Volume 68 — Issue 4 (Dec 2003)

The 1956 hectares comprising Piscataway and Fort Washington National Parks in Prince Georges and Charles Counties, Maryland were surveyed for vascular plants from 1995 to 2002. Additional historic occurrences were determined through searches of local herbaria. A total of 988 vascular plant taxa representing 973 species, nine varieties and six hybrids from 495 genera in 142 families were documented within the parks. Of these, seventeen are known only from historic specimens or records. Habitat associations and relative frequency of occurrence was noted for each taxon. A total of 21 habitats were identified and they were described along with their geology and hydrology. Non-native taxa comprised 25.3% of the vascular flora within the parks. Thirty-one of the documented plants have State endangered or threatened status.

Canaan Valley, West Virginia, contains one of the largest inland freshwater wetland ecosystems of bogs, marshes, wet meadows, and shrub and forested wetlands in the eastern United States. This study uses aerial photography and ground truthing activities to produce GIS-based vegetation maps for 1945, 1975, and 1997, in order to track changes in plant community types and to construct plant successional models. Between 1945 and 1997, there was an increase in the area covered by northern hardwood forests and Spiraea alba and Hypericum densiflorum shrub thickets, but only a limited increase of Picea rubens dominated forests. Beaver activity along waterways became an important factor in determining successional trends, causing shrub swamps to be converted to wet meadows and marshes. The least successional change occurred in bogs and old fields located at the base of surrounding slopes. Overall, successional trends appear to follow rather predictable patterns for uplands and lowland habitats. However, there is little evidence to suggest that P. rubens will replace hardwood species on the uplands.

There is increasing interest in the restoration of classic landscapes such as native grasslands in the northeastern United States. This study characterizes the species composition and range of natural variability of xeric limestone prairies in unglaciated central Appalachia. Bouteloua curtipendula, the characteristic and dominant graminoid, is the primary indicator species for xeric limestone prairies in Pennsylvania, and its distribution is restricted to dry, south-southwest facing slopes within the valleys of the Ridge and Valley Physiographic Province. Only ten such prairies are known to remain in Pennsylvania and their total area is <1 hectare. A total of 126 native taxa representing 40 families was found on the extant prairies. Twelve rare, state-listed prairie species were found on these sites, and their state-wide distributions also were concentrated in the Ridge and Valley. In comparison to Ohio and West Virginia limestone prairies, community structure, determined by dominant graminoids, was identical, but species composition, particularly related to prairie forb assemblages, was slightly different (average Sorenson similarity coefficient = 38%). The limestone prairies of Pennsylvania have a strong association with the Opequon soil series, which is found only in limestone valleys. Xeric limestone prairies in Pennsylvania likely were never a large component of the presettlement landscape, were likely concentrated in central Pennsylvania, and currently serve as important refugia for uncommon eastern prairie species.

The woody vegetation of three forest communities dominated by Quercus muhlenbergii Engelm. (yellow chestnut oak) were studied. All sites examined were located on steep, south-facing hillsides in central Illinois. Yellow chestnut oak accounted for 35-50% of the basal area and density on these sites, had an importance value of 72 to 115 (possible 200), dominated most diameter classes, and was common as small diameter trees. Other overstory components included other oak species, along with hickories (Carya spp.), and ashes (Fraxinus spp.). Dominant understory species were black haw (Viburnum prunifolium L.), American elm (Ulmus americana L.), red elm (U. rubra Muhl.), redbud (Cercis canadensis L.), and hack berry (Celtis occidentalis L.). Canopy openings caused by fire, death of veteran trees, and tree falls, should allow this cover type to be self-perpetuating.

Noteworthy Collections: South Carolina

At the 2003 Association of Southeastern Biologists meeting in Arlington, Virginia, the Southern Appalachian Botanical Society sponsored a symposium entitled “The Crisis in Field Botanical Training: Loss of People and Knowledge.” This symposium was organized by Larry Stritch and Wayne Owen from the United States Forest Service and by Mike Baranski, Bill Martin, Mike Dennis, Andy Ash, and myself. The origin of the symposium originated with a call to Mike Baranski from Larry Stritch lamenting the lack of qualified field botanists to be hired by state and federal agencies.

Water is the preference of choice as an algal medium in a recent EPA manual (Stevenson and Bahls 1999) and with researchers for studying non-diatom algae. Other studies use syrup mediums (Patrick 1936, Stevenson 1984, Taft 1978) and Pleurex (Hanna 1949, Von Stosch 1974) to study primarily phytoplankton. Syrup medium uses a gluteraldehyde solution, a known carcinogenic substance, to fix the algal cells before mounting. Pleurex is not commercially produced. It is a labor-intensive procedure to make in the laboratory and is not a favorable medium for all algal species (Von Stosch 1974). Typical sealers for water-based slides are fingernail polish and polyurethane (Stevenson and Bahls 1999). These sealers are permeable to water vapor, and the sample gradually dries out within days to weeks for fingernail polish and a few months for polyurethane. While I have used both fingernail polish and polyurethane, I prefer epoxy as a major improvement to other sealers.