The Maryland County distribution of the species of Solidago (sensu stricto), based on an examination of currently extant specimens, is shown in a series of dot maps.
The Maryland County distribution of the species of Solidago (sensu stricto), based on an examination of currently extant specimens, is shown in a series of dot maps.
Sears Woods and Carmean Woods form a 63 ha complex of old-growth, mostly primary forest in the till plains of north-central Ohio. Mesic uplands of the complex are dominated by Acer saccharum and Fagus grandifolia, with Quercus alba, Q. borealis, and Fraxinus americana also common in the canopy. The sapling size class is strongly dominated by Acer saccharum; Quercus and Fraxinus spp. are essentially absent from the sapling size class. This part of the complex corresponds well to descriptions of pre-settlement beech-sugar maple (F. grandifolia–A. saccharum) forest, though the substrate and topography suggest wet beech (F. grandifolia) or beech-oak-red maple (F. grandifolia-Quercus spp.-A. rubrum) forest should have occupied this site. The canopy of the lower, poorly-drained portions of the preserve is dominated by Acer saccharum, Tilia americana, Ulmus americana, and Acer saccharum; the sapling size class was dominated by A. saccharum and U. americana. With the exception of the relatively-high abundance of A. saccharum, the bottomland areas correspond well to early descriptions of the red oak-basswood (Quercus borealis–Tilia americana) phase of the elm-ash (Ulmus–Fraxinus) swamp forest. A Markov Chain model based on most-probable-replacers of current canopy trees predicts a strong increase in A. saccharum and F. grandifolia importance, with a corresponding decrease in Quercus and Fraxinus spp. abundance in the future. The predicted increase in A. saccharum is consistent with the pattern of replacement in 23 recent treefall gaps in the complex. We suggest that changes in regional drainage altered the hydrological regime in such a way as to permit A. saccharum to establish in areas historically too poorly drained for it. In addition, we suggest that the current disturbance regime, which is dominated by small patch size disturbances, fosters the growth of A. saccharum saplings, but not Quercus saplings, into canopy size classes.
The well-known European alternate-leaved spleenwort, Asplenium ✕alternifolium is reported for the first time in the New World. It is the natural hybrid of A. septentrionale (L.) Hoffm. and A. trichomanes L. Solitary plants were found in two localities in Hardy County, West Virginia, associated with the parents and other spleenworts on rock outcrops. Confirmation of their hybrid nature was accomplished by morphological, cytological, and isozyme comparisons.
This paper presents a list of 244 taxa identified during a three-year study of the phytoplankton communities in Lake Barkley. Taxa belonged to Cyanophyceae (8.6%), Chlorophyceae (28.7%), Euglenophyceae (6.1%), Dinophyceae (2.0%), Cryptophyceae (1.2%), and Bacillariophyceae (53.4%). Additionally, seasonal distributions of phytoplankton standing crops in two embayments and at one main channel site are shown. These data indicate that Cyanophyceae and Bacillariophyceae dominate the phytoplankton in Lake Barkley.. [sic]
A descriptive study of the vascular flora and vegetation was conducted during 1987 on a 12-year-old contour surface-mined area, the 2.5 ha Trace Branch site, in Rockcastle County, Kentucky. An annotated list of vascular plants comprised 272 specific and infraspecific taxa (220 indigenous, 52 nonindigenous) from 63 families. These taxa consisted of 13 Pteridophyta, 4 Pinophyta, and 255 Magnoliophyta. The numerically most important plant families were the Asteraceae (43), Poaceae (36), Fabaceae (25), Cyperaceae (11), and Rosaceae (11). A total of 160 Rockcastle County distributional records were documented. Hedeoma hispidum Pursh, an endangered species in Kentucky, was present on the site. The plant communities were described on the bench, outslope, highwall, access road, and seasonally wet habitats. Twenty-four herbaceous and woody species (10 indigenous, 14 nonindigenous) have persisted of the 30 initially planted by personnel of the Northeastern Forest Experiment Station, USDA Forest Service. Vegetation consists of a complex mosaic of natural and semi-natural plant communities on unplanted and planted areas on the mined site. Flora and vegetation are a result of invading native and naturalized species, planted native and exotic species, mine soils characteristics, and habitat diversity created by surface mining and reclamation in 1975.
The spring and autumn seed bank in a Fraxinus caroliniana dominated floodplain swamp of the St. Johns River in Florida was examined. Soil cores were collected at 14 microsite types. The seed bank was dominated by the single species Ulmus americana in spring and Cephalanthus occidentaks in autumn. Mean density of seeds in both the top 5 cm of substrate and at 5-10 depth decreased significantly from spring to autumn, principally due to the germination of Ulmus americana seeds. The highest viable seed density was on stump microsites (611 seeds/m2 in spring and 0 seeds/m2 in autumn) and the lowest viable seed density was on logs (127 seeds/m2 in spring and 25 seeds/m2 in autumn). Seeds of most of the dominant tree species in the floodplain were absent from the seed bank.
Fruiting branchlets of Cornus florida were artificially defoliated to determine the extent and nature of reproductive adjustment in this species. Infructescence abortion and fruit abortion increased in response to defoliation, but only fruit abortion was statistically significant. Defoliation significantly decreased fruit size. Reproductive adjustments were roughly proportional to the extent of defoliation, with fruit set decreasing about 6% and fruit biomass decreasing about 8 mg per leaf removed. Fruit development continued even after complete defoliation, indicating significant assimilate production of developing fruits and/or ability of branchlets to draw assimilate from neighboring branchlets. We conclude that in flowering dogwood assimilate supply controls the number of filled fruits and the rate at which they grow.
Three populations of Calamagrostis cainii Hitch. were discovered in North Carolina. Two were found at Craggy Pinnacle and one was found in the Black Mountains. These are the first discoveries of this species elsewhere than Mt. LeConte, Tennessee.
In the course of my work on the treatment of the Caryophyllaceae for the Generic Flora of the Southeastern United States (Rabeler, in prep.), I came across a specimen of Moenchia erecta (L.) Gaertn., Meyer, & Scherbius from South Carolina. Although recently reported from California (Taylor and Ahart 1983), Oregon (Peck 1961) and British Columbia (Szczawinski and Harrison 1973), this species last appeared in the eastern North America literature in 1913 (Britton 1913). Since this species had occasionally appeared in nineteenth century manuals, I thought it appropriate to attempt verification of these early records.