Volume 53 – Issue 4 (Dec 1988)

Eight native species (Carex albolutescens, C. oligosperma, Diplachne fascicularis, Hypericum pyramidatum, Iris versicolor, Juncus trifidus, Scirpus torreyi, and Stellaria calycantha), seven introduced species (Betula alba, Hedera helix, Hieracium umbellatum, Hosta ventricosa, Koelreuteria paniculata, Lunaria annua, and Spiraea vanhouttei) and a native form (Asplenium platyneuron f. hortonae) are reported as additions to the known flora of West Virginia. Juniperus communis, known from the state as an introduction, is reported to be native.

Ring widths of mature white oak trees were compared on 16 upland hardwood sites in the South Carolina Piedmont. Each site was classified as being in one of four community types forming a vegetation continuum along an environmental gradient ranging from xeric upland flats to mesic lower slopes. Ring widths were analyzed to determine the effect of climate on radial growth of white oak over the environmental gradient.

The ring-width chronologies of the xeric community types (1 and 2) showed more ring-to-ring variation then the more mesic community types (3 and 4), agreeing with the hypothesis of decreasing climatic stress from the xeric to mesic community types.

Based on response function analysis, important monthly climatic variables in white oak summerwood radial growth included: mean temperature for August, October, and December (prior year), March, May, June, and July (current year), and total precipitation for August and September (prior year), and January through June (current year). There were four more significant monthly climatic variables in the summer-wood ring-width response functions than in the total ring-width response functions, agreeing with the hypothesis that there is more climatic information in the summer-wood portion of radial increment than in total ring width.

Although visual analysis of total ring-width chronologies indicated that the length of the recovery period following a drought event was longer for trees on community type 1 (xeric) than on community type 4 (mesic), statistical analysis found no difference in the length of the recovery period between these two community types.

Leaves of 56 species from two north-west Georgia cedar glades were sectioned and stained with I₂KI. Four species had Kranz anatomy, which is indicative of C₄ photosynthesis. Since none of the four species with Kranz anatomy is endemic to cedar glades, it appears that the combination of edaphic and climatic conditions present in southeastern cedar glades is insufficient to select for species with C₄ photosynthesis. A species lacking Kranz anatomy, Senecio plattensis Nutt., represents a range extension into Georgia.

Several range extensions have been documented on Pigeon Mountain in northwest Georgia (Walker County). The first three reported here are new records for Georgia (not cited by Coile and Jones 1985), but listed in the new atlas (Jones and Coile 1988).

Before reviewing our current and projected state of affairs, I would like to express thanks and appreciation, on behalf of the membership, to last year’s SABC Council and committee chairpersons for their service to the Club. Robert Haynes provided outstanding leadership during his tenure as President and a special thanks is extended for his efforts in helping prepare a handsome SABC color brochure that will be especially useful in future promotions and recruitments. Copies are available upon request to any member who would like to use them to help promote SABC.

All previous investigators have reported Nitella flexilis (L.) Ag. as the dominant macrophyte in Mountain Lake, Virginia. Reevaluation of these earlier studies along with detailed morphological measurements and chromosome counts on fresh collections and cultured material from the lake now indicates N. megacarpa T.F.A. as the monospecific population.

The southern woodfern Dryopteris ✕ australis is the aborted-spore backcross hybrid of the allotetraploid D. celsa with one of its parents, D. ludoviciana. From previous reports, this hybrid is known to occur at several localities with D. celsa well north of the present range of D. ludoviciana. Examination of vigorous clones, misidentified as D. celsa, in southeastern Virginia and southeastern Tennessee has resulted in their identification as D. ✕ australis based on morphology, aborted spores, chromosome counts, and isoenzyme profiles. Although both localities are within the range of D. celsa, the hybrids are several miles from the nearest known D. celsa populations and much farther from the nearest known D. ludoviciana site. Their occurrence may be due either to local hybridization, probably involving dispersed spores, or to functioning of viable unreduced spores by D. ✕ australis itself.

The vegetation in some southern Appalachian grassy balds is changing as shrub and tree invasion reduces the dominance of grasses. Successional changes were documented in one grassy bald, the Judaculla Fields, by monitoring the vegetation in 1/2 x 2 m permanent plots over a five-year period. Overall, the grass and mixed herb cover decreased by 25 and 21%, respectively, while woody shrub and tree species cover increased by 239 and 88%, respectively. The primary species invading the grassy areas was the low-bush blueberry (Vaccinium pallidum Aiton). The increase in conifer saplings present was probably a function of large seed crops during the five-year period. However, the rapid shrub invasion and loss of spruce-fir seed source presently observed is likely to preclude either the formation of spruce-fir forest or the maintenance of the grassy status of the bald.

Cover and density of ground-layer species were measured in belt transects in three central Maine forests to (i) analyze pattern of the community and individual species, and (ii) determine if a relationship exists between tree canopy type and ground-layer species distributions. Although the ground-layer vegetation in each of the three forest stands contained about the same number of species, only three common species occurred at all sites: Maianthemum canadensis, Trientalis borealis, and seedlings of Acer rubrum. Most species were clumped, although in one stand several species were regularly distributed. Some species such as M. canadensis were clumped in one forest and regularly distributed in another. Based on an analysis of community pattern, vegetation in the understory of the two forests occupying south-facing slopes was spatially heterogeneous, whereas the ground-layer on the north facing slope appeared homogeneous. In each stand, community pattern varied due to the occurrence of species such as Viburnum alnifolium which had low frequency but high coverage values. The amount of cover of several ground-layer species was related to canopy type in two of the three forests. Patch sizes of the two common herbs M. canadensis and T. borealis were related to canopy type and possibly asexual propagation.

Noteworthy Collections: Tennessee, Maryland, Pennsylvania, and West Virginia