Volume 63 – Issue 2 (June 1998)

Although Penstemon tenuiflorus and P. hirsutus of eastern North America generally are regarded as closely-related species, the taxonomic level of their distinctiveness has been questioned. Based on evidence from herbarium, common garden, SEM, and field studies, we conclude that these two taxa are distinct at the species level. They differ in leaf pubescence, flower color, geographic distribution, and habitat preference. A key to the 18 taxa of Penstemon occurring east of the Mississippi River is provided.

Keys and descriptions are presented for the 12 genera and 31 species of Acanthaceae in the southeastern United States. The largest genera include: Ruellia (9 spp., 4 sspp., 4 var.) and Justicia (6 spp., 2 var.).

Bad Branch is located on the southeast face of Pine Mountain in southeastern Kentucky near the Virginia border. One hundred and forty-nine moss species were documented for the Bad Branch watershed. Cirriphyllum piliferum, Ephemerum crassinervium, Oncophorus raui, Polytrichum strictum, Sphagnum cuspidatum, Brachythecium populeum, and Sphagnum quinquefarium are newly reported for Kentucky with the latter two species also new for the Cumberland Plateau. Bad Branch also has an unusually diverse Sphagnum flora (10 species) for the Cumberland Plateau and Cumberland Mountain regions.

A new species, Echinodorus floridanus, from extreme western panhandle Florida, USA is described, and characteristics to separate it from the other species of Echinodorus are discussed. The new species is known only from the type locality.

This paper represents the continuation of an investigation into the Flora of Rabun County, Georgia, begun by the staff of the Louise Gallant Herbarium in 1989, and presents the results of approximately 70 field trips made during the 1995 and 1996 collecting seasons. A brief site description is followed by the presentation of a catalogue of vascular plants. The survey records 273 species, 158 county records, 6 species new to Georgia, and 5 species listed as Special Concern by the Georgia Department of Natural Resources. 972 vascular plant species are now recorded for Rabun County.

A status survey to determine population size and describe community structure was conducted during 1995 at each of seven sites where Dirca palustris (leatherwood) has been known to grow in South Carolina. Populations ranged in size from eleven to over 400 plants with a typical population size being about 100 plants. Vegetation analyses using transect lines throughout the population were used to determine the importance values of tree species. The surveyed populations were located in mesic mixed forests where Pinus taeda (loblolly pine) and Liquidambar styraciflua (sweetgum) were prevalent. Plants grew along stream floodplains and levees in well drained sandy to sandy loam soils which were slightly acidic.

Two streams in the West Sandy Creek watershed of Henry County, Tennessee were studied for primary production. Bailey Fork Creek is a relatively undisturbed stream, while Holly Fork Creek is a channelized stream. In these sandy-bottomed, chemically-similar streams, twenty line transects were used to estimate the volume of submerged wood and to establish plots for photoautotroph sampling. Wholestream gross primary production of unchannelized Bailey Fork Creek was approximately ten times greater than channelized Holly Fork Creek in August 1993 as estimated by diurnal changes in dissolved oxygen. Unchannelized Bailey Fork Creek contained approximately ten times more chlorophyll a than Holly Fork Creek due to the large biomass of periphyton attached to the large volume of submerged wood. Sand-associated periphyton and macrophytes were minor contributors to whole-stream primary production in Bailey Fork Creek (15%), but were the major contributors in Holly Fork Creek (96%). The results suggest that periphyton associated with wood is the most important contributor to primary production in the streams of the West Sandy Creek watershed and that wood removal from sandy-bottom streams may significantly reduce primary production.

Chromosome counts from 44 populations, representing four species of Chelone from throughout its range in eastern North America, are reported for the first time and counts from six populations examined by other researchers are discussed. Chromosome number determinations in Chelone generally agree with those of previous work and suggest a base number of x = 14 and an euploid series: C. cuthbertii, C. glabra, and C. lyonii are 2n = 28; C. obliqua populations in the southern Blue Ridge are 2n = 4x = 56; whereas C. obliqua populations from elsewhere are 2n = 6x = 84. The taxonomy of species, distribution of chromosome races, and cytotypes are discussed.

This paper presents a list of 41 Carex taxa vouchered for the Buffalo National River in north central Arkansas, a list of 23 Carex taxa considered as possible additions, and briefly discusses potential for undescribed taxa. The total (64) compares with 59 taxa known for Baxter County, Arkansas, an adjoining county the author collected extensively, and with 122 Carex taxa listed for Arkansas.

Sapium sebiferum (L.) Roxb., a fast growing tree in the Euphorbiaceae, has rapidly spread and changed many aspects of plant community structure in the southeastern United States (Harcombe et al. 1993, Bruce et al. 1995). It is a major pest of natural coastal tallgrass prairie in Louisiana and Texas and is one of the first and most persistent invaders of abandoned agricultural land (Ewel 1986, Bruce 1993, Jubinsky 1995) and bottomland hardwood forest.