Block, T.A., and A.F. Rhoads. 2011. Aquatic Plants of Pennsylvania: A Complete Reference Guide. Illustrations by Anna Anis´ko. University of Pennsylvania Press, Philadelphia, Pennsylvania. 308 p. Hardcover, $60.00. ISBN 978-0-8122-4306-2.
The collections listed below were made on recent Haitian fieldtrips by the second author, and each collection is associated with one or more photographs of the living plant. Clidemia umbellata (Mill.) L.O. Williams (MELASTOMATACEAE)— Dept. de l’Artibonite: near Morne Boeuf Mecranium integrifolium (Naud.) Triana subsp. neibense (Skean) Skean (MELASTOMATACEAE)— Dept. de l’Artibonite: near Morne Boeuf Miconia basilensis Urb. & Ekman (MELASTOMATACEAE)— Dept. de l’Artibonite: Massif du Nord, near Morne Basile
Lathyrus sylvestris L. (FABACEAE)—Polk County: 2.3 km(by road) E on US Hwy 64 from Ocoee Dam No.1 Significance. This is the first collection of L. sylvestris from Tennessee. This introduced species has an irregular distribution across eastern North America; seven states in the western USA and British Columbia, Canada (USDA 2011). Prior to this collection, the nearest documentation of this species was from Rutherford County, North Carolina in 2005 (Liu et al. 2005).
Preview: Stenanthium leimanthoides (A. Gray) Zomlefer & Judd, commonly known as pine barren deathcamas, is classified in the Melanthiaceae family and is a former member of the polyphyletic genus Zigadenus (Zomlefer and Judd 2002). It is spottily distributed from New York and New Jersey south through West Virginia to North Carolina and Tennessee. It also appears in the Gulf Coastal Plain, where it is a rare taxon ranging from west central Georgia (Carter et al. 2009) to south Alabama, northwest Florida (Anderson 1995), south Mississippi, and southeast Louisiana, perhaps extending as far west as east Texas (USDA Plants Database 2012). Plants in the Gulf Coastal Plain are generally very robust, sometimes attaining heights of two meters or more. Flowering in the latter region is mostly from May through the middle of June, and plants typically have paniculate inflorescences in which each branch (raceme) is elongate and tight.
ABSTRACT The primary objectives of this project were to determine which species of Crotalaria (Fabaceae) occur in Alabama and the county distribution of each species. Crotalaria, known commonly as rattlebox, is recognized as consisting of seven species in Alabama. The most common species are Crotalaria sagittalis, C. rotundifolia, and C. spectabilis. The less common species are C. purshii, C. lanceolata, C. pallida, and C. ochroleuca. In Alabama, introduced species of Crotalaria (C. lanceolata, C. ochroleuca, C. pallida, and C. spectabilis) generally have showier inflorescences and reach greater maximum heights than native species (C. purshii, C. rotundifolia, and C. sagittalis). The dichotomous key and descriptions we present are modifications from earlier authors; however, all measurements are based on morphological features of the vegetative and reproductive structures of the more than 460 specimens studied during this project. Data for the county-level distribution maps were compiled entirely from herbarium vouchers.
ABSTRACT Forest fragmentation continues to increase throughout the United States and many studies show a trend toward taxonomic homogenization in fragments. Characterizing the species composition and diversity of remaining forest fragments and identifying factors influencing composition and diversity can help to inform management practices and aid in setting conservation priorities. Because influencing factors tend to be site-specific, studies of local and regional fragment community composition are needed. We studied forest community composition and diversity in four forest fragments of the Shenandoah Valley, Virginia.We found significant (p < 0.05) differences in tree species diversity (H’) as well as abundance of exotic species across forest fragments. In addition, results of nonmetric multidimensional scaling (NMS) showed that there were significant differences in species composition among fragments. Soil properties and stand age, in addition to presence of exotic species, were the most important factors influencing differences in tree species composition. Older fragments on high
ABSTRACT Within a successional context, the vegetation associated with the cedar glade ecosystem in middle Tennessee develops from bare limestone bedrock to subclimax redcedar, preclimax oak-hickory, and climax mixed hardwood forests. Studies on the composition and structure of forests associated with cedar glade–forming limestones (Lebanon, Ridley) are rare. We sampled the canopy and understory of six forest stands in middle Tennessee on these limestones. Observed number of canopy species was 14–24 across stands; estimated richness was greater by 1–3 species (bootstrap) or 3–6 species (first-order jackknife) than observed richness. With the exception of Ailanthus altissima in one stand, all other canopy species were native. Juniperus virginiana, Fraxinus americana, Carya ovata, and Quercus muehlenbergii were primary canopy components in 4 or 6 stands, and C. glabra, Q. shumardii, Ulmus alata, F. quadrangulata, Q. alba, and Q. velutina in 2–3 stands. When we included stands from a previously published study (most on
ABSTRACT The high marsh in southeast Atlantic coast salt marshes forms a relatively small but ecologically important transition zone between low marsh and the terrestrial shoreline. However, long-term trend data from high marshes are limited to a few studies. Permanent plots established in a high marsh near Waties Island in northeast South Carolina were measured for plant coverage from 2002–2010. At the beginning and at the end of the study, four groups of plots were identified: mixed indicated by Borrichia frutescens, Distichlis spicata, and Fimbristylis castanea; Juncus indicated by Juncus roemerianus; Salicornia indicated by Salicornia virginica; and Spartina indicated by Spartina patens. Ordination of the 2010 plot data and soil analyses produced clear separation of the groups along a single dominant axis with Salicornia and Juncus groups at the high end of a salinity gradient and the Spartina group at the high end of soil organic matter gradient. Comparison of
ABSTRACT Glossy buckthorn (Rhamnus frangula L. or Frangula alnus Mill.) is a tall shrub to small tree, native to Eurasia and North Africa, which can invade both wetland and upland sites in northeastern and midwestern North America. Invasion by R. frangula is often patchy in riparian savannas of the Allegheny High Plateau of northwestern Pennsylvania: Some sites are heavily invaded, whereas others nearby are sparsely invaded or not invaded at all. Because microtopography in riparian savannas can be diverse, with slightly elevated dry hummocks and wet depressions providing habitats for a range of upland and wetland plant species, we tested the hypothesis that the patchy nature of R. frangula invasion of riparian savannas is determined in part by soil drainage, which may ultimately affect shrub establishment and growth. We used depth to mottling by iron oxides as a primary, indirect measure of soil drainage and inundation and also measured the
ABSTRACT In the southern Appalachians, Rhododendron maximum L. (Ericaceae) is a key evergreen understory species, often forming a subcanopy in forest stands. Little is known about the significance of R. maximum cover in relation to other forest structural variables. Only recently have studies used Global Positioning System (GPS) technology as a field-based method to map the perimeter of shrub patches as a means of estimating canopy cover. We assessed the viability of using GPS technology to accurately measure R. maximum canopy cover in mountainous terrain; and we compared canopy cover to other R. maximum abundance variables, forest structural attributes, and environmental factors. We selected forty 20 3 40 m permanent plots at Coweeta Hydrologic Laboratory in western North Carolina to employ a variety of methods (visual estimates, GPS, and x-y coordinate measurements) to estimate canopy cover of R. maximum within each plot. We found a positive relationship between the GPS