Noteworthy Collections: Maryland and North Carolina
Noteworthy Collections: Maryland and North Carolina
Cyperus compressus L., C. croceus Vahl, C. difformis L., C. engelmannii Steudel, and C. microiria Steudel are documented for the first time from Kentucky. The range of C. brevifolioides Thieret & Delahoussaye is extended from two to 26 counties. The taxonomic characteristics of C. engelmannii are discussed.
This very impressive volume is a revision of the 1974 classic Agriculture Handbook 450-Seeds of Woody Plants in the United States. The 386 genera covered are more than double that of the previous edition. The treatment includes important timber and wildlife species, many small trees, shrubs and vines useful in landscaping, and selected Asiatic taxa. Most literature citations from Handbook 450 are not repeated, but over 1,000 new citations from the last two decades have been added.
Fraxinus tomentosa has until recently been considered a very rare component of Ohio’s swamp forest communities. Until 1992 only four populations were known in Ohio, all in the extreme southwest corner of the state. Intensive fieldwork in 1992 focusing on locating additional F. tomentosa populations resulted in finding 28 new sites in 11 counties. These populations were scattered throughout the glaciated till plains and the lake plain of Lake Erie, revealing a much wider distribution in Ohio than was previously suspected. As a consequence of this survey F. tomentosa was located for the first time in Michigan and Pennsylvania.
Echinacea tennesseensis (Beadle) Small is a federally endangered vascular plant species endemic to the limestone cedar glades of the Central Basin of Tennessee. The vegetation associated with each of the five known populations of E. tennesseensis was sampled in 1987, and its population demographics were analyzed based on observations of 492 marked individuals over two years. Although vegetative cover and species’ frequency varied among sites, Echinacea tennesseensis is an important component of the vegetation at all five sites, and a dominant at three sites. The vegetation of four sites is relatively similar, but the fifth site differs in species composition and reflects a history of human disturbance. In both growing seasons mortality was highest among the smallest plants. A critical stage of growth (>30 cm total leaf length) at which survivability increases was identified. Plants that have not reached this stage have only a 50% chance of surviving an extreme summer drought such as that of 1988. Nearly half of the plants that produced flowers in 1987 did not produce flowers in the exceedingly dry summer of 1988; however, of these, 68% flowered in 1989. In addition, mortality was higher in year 1 (1987-88) than in year 2 (1988-89). These differences between years are attributable to the higher rainfall recorded during the 1989 growing season, and they demonstrate that flowering is sporadic and most likely dependent on growing season rainfall.
The vascular flora and arborescent vegetation of a 90 km2 area of western Isle of Wight County were studied. Located on the southeastern Coastal Plain of Virginia, the study area lies on the Isle of Wight Plain along the Blackwater River, and surrounds the last remnant of longleaf pine-turkey oak pine barrens in Virginia. It also lies in the transition zone between the Southern Mixed Hardwood Forest of the Southeast and the Oak-Hickory-Pine Forest of the Middle Atlantic Coast. Vegetational analysis of representative forest types in the area was completed using the Bitterlich-circular quadrat sampling method. The present study suggests that the region is characterized by a more southern flora and vegetation than areas only slightly to the north (e.g., the Virginia Peninsula). Six hundred and four species representing 357 genera in 113 families of plants were documented. Sixty-eight of these were newly recorded for the county, and three of these were records for the southeastern Coastal Plain of Virginia. Nine of the species are very rare to extremely rare in the state, and seventeen others are rare to uncommon.
Electrophoresis of isozymes was carried out on samples from six populations of Trillium pusillum Michaux from the mountains and coastal plain of Virginia; samples of T. pusillum var. ozarkanum from Arkansas and T. pusillum from Alabama were also included for comparison. Twelve loci from nine enzyme systems were found to be consistently decipherable; of these, eight were polymorphic. The mean expected heterozygosity (H,) for all populations was 0.140. Chi-square analysis of genotype frequencies and calculated values of Wright’s Fst were consistent with an outcrossing breeding system with near random mating within each population, a result also suggested by studies of pollination using pollinator exclosures. The mean value for Wright’s Fst was calculated to be 0.414, indicating extensive population differentiation. The gene flow parameter, Nm, was estimated from Fst to be 0.354, suggesting a low level of gene flow among populations. This is consistent with what is known of pollination and seed dispersal. No compelling evidence was found for separate varietal status for the mountain populations from Virginia, and it is recommended that all Virginia populations be considered a single variety.
A morphological study of the Trillium pusillum Michaux complex was undertaken to clarify the range of variation and taxonomic standing of ten populations in the coastal plain of Virginia and southeast Maryland and two populations in the mountains of Virginia. Morphological measurements were taken from fresh material and analyzed using univariate analysis of variance and nested analysis of variance, and the multivariate techniques of stepwise discriminant analysis and canonical discriminant analysis. No unequivocal geographic patterns of variation were found. The mountain populations were found to have significantly broader leaves and shorter pedicels, but some coastal plain populations were equally divergent if other characters were examined. It is suggested that all of these populations be considered Trillium pusillum var. virginianum Fernald or more simply Trillium pusillum.