Volume 64 – Issue 2 (June 1999)

Between June 1994 and May 1995, we measured plant species densities, species richness, tree basal area, and soil chemistry in thirty, 81-ha sandhill plots at Eglin Air Force Base, Florida. Comparisons were made between three sandhill types: (1) fire-suppressed, (2) burned with bluestem (Andropogon spp. and Schizachyrium spp.) dominance, and (3) burned with wiregrass (Aristida beyrichiana) dominance. Species assemblages for each sandhill condition are discussed. Species richness and densities of forbs, clonal shrubs, and graminoids were highest in burned and wiregrass-dominant plots. Fire-suppressed plots harbored lower stem densities of herbaceous and woody groundcover species, but their floristic composition was similar to that of burned plots. The majority of fire-suppressed plots were more floristically similar to the burned and bluestem-dominant sandhills. Soil chemistry did not correlate strongly with observed vegetation patterns, but there is evidence that soil texture influences species assemblages within sandhill communities. Whereas fire frequency appears to have its greatest effect on vegetation structure and relative dominance of certain species or life-forms, plant species richness, and species composition appear to be largely determined by edaphic variation and soil disturbance histories.

Forests dominated by red spruce (Picea rubens Sarg.) and Fraser fir [Abies fraseri (Pursh) Poir.] occupy the highest elevations of the southern Appalachians. These forests have been severely impacted by logging early in this century and by the depredations of an exotic insect, the balsam woolly adelgid (Adelges piceae Ratz.). This study quantifies the structure and dynamics of logged and old-growth stands in the spruce-fir ecosystem and concentrates on sites that have received little previous research attention. A set of 39 permanent plots established in late 1984 was resampled in late 1991. Logged sites differed from old-growth stands by having greater mean annual diameter growth increments, higher rates of tree recruitment from the understory, and spruce age distributions skewed toward younger age classes. Greater densities of deciduous taxa and lower abundances of spruce in logged stands relative to uncut stands demonstrate that recovery from logging is a continuing process. These differences in stand structure and dynamics suggest that it will probably be decades before forest communities in logged sites resemble those in old-growth areas. Logged and uncut spruce-fir forests may also respond differently to future disturbances. Spruce mortality rates were not unusual compared to earlier research, and fir mortality rates were lower than those in earlier research, suggesting that the initial wave of adelgid-caused fir mortality is virtually complete.

A Late Pleistocene/Holocene sediment core from St. Catherines Island, Georgia (31°37’N latitude, 81°09’W longitude), was found to contain dense peat at a depth of 5.02-5.12 meters. The peat was radiocarbon dated (AMS) at 47,620 ± 2,500 years BP, and contains a palynoflora consisting of 85% monolete pteridophyte spores. No perispores were recovered, so unequivocal identification of the spores based on surface morphological characteristics is impossible. The associated palynoflora of the peat (taxa such as Chenopodiaceae-Amaranthaceae, Asteraceae, and Liquidambar) was used to infer the habitat and environmental conditions which were present at the depositional site; these inferred conditions were used in combination with comparisons of mean spore size to modern fern taxa (e.g., Woodwardia, Thelypteris, Dryopteris) in order to identify the probable producer of the fossil spores. The data indicate that the most likely candidate for the pteridophyte is Woodwardia virginica. Paleoecological reconstructions suggest the presence of a dense stand of ferns growing alongside characteristically southeastern floral elements. The long-term stability of southeastern coastal plant communities is supported by this pteridophyte-dominated assemblage.

The vascular flora of Cove Point Marsh, a barrier wetland in Calvert County, Maryland, was surveyed from April 1996 to October 1997. A total of 304 species representing 305 varieties and one hybrid from 208 genera in 90 families were recorded from at least 10 community alliances in the study site. Of the 304 vascular taxa collected, 192 were principally associated with the wetland and 112 were primarily associated with the barrier dune. Of these, only 3.1% of the wetland taxa but 35.7% of the barrier dune/ beach taxa were not native to Maryland. At least 21 taxa were common to both the wetland and barrier dune habitats. Thirteen of the documented taxa were state listed as threatened or endangered and two of the plant community alliances were first reports for Maryland.

Oak-hickory-pine (Quercus-Carya-Pinus) forests of Hot Springs National Park in the Ouachita Mountains of Arkansas were analyzed and their composition compared with other forests in the Ouachitas, with forests of the mountains of the Arkansas Valley Region, and with oak-hickory-pine forests of the Piedmont east of the Mississippi River. In Hot Springs National Park, abundant Pinus echinata forms a background against which the abundances of hardwood species vary. DCA and CCA ordinations revealed that the abundances of hardwood species (but not pine) were strongly related to aspect and topography, with Quercus marilandica, Q. stellata, Carya texana, and the normally mesophytic Carya cordiformis abundant on southerly and southeasterly exposures; with other oaks (Quercus alba most important, but also Q. velutina, Q. falcata, Q. rubra) and mockernut hickory (Carya tomentosa) most abundant on nearly level terrain or less xeric directions of exposure; and with Liquidambar styraciflua and other more mesophytic non-oak species most abundant in ravines and along streams, where soils also had higher Na and Ca values. Hot Springs National Park forests were quite similar to those of other sites in the Ouachita Mountains, though with much less Quercus shumardii than has been reported in the western Ouachitas. Ouachita Mountain oak-hickory-pine forests are much like those of the Piedmont of the eastern United States, but differ from the latter in the presence and high abundance of Carya texana, which does not occur east of the Appalachians, and in lacking Liriodendron tulipifera and Quercus prinus, neither of which ranges as far west as the Ouachitas. The information in this article is offered as a partial remedy for the omission of that portion of the Oak-Hickory-Pine Forest Region west of the Mississippi from the most recent major treatment by Martin, Boyce, and Echternacht of the vegetation of the southeastern United States.

We investigated the dynamics of woody, characteristic bayhead species (Gordonia lasianthus, Ilex cassine, Magnolia virginiana, Myrica cerifera, and Persea palustris) invasion into 50 seasonal ponds at three sites in south central Florida. Individuals of Gordonia lasianthus and Persea palustris were concentrated in the shallow Panicum abscissum zone, while Ilex cassine, Magnolia virginiana, and Myrica cerifera were concentrated in the fringing Serenoa repens zone. Trees of all species had the largest diameters in the cutthroat zone. Deeper pond zones were less often invaded. The natural log of bayhead invasion density was negatively correlated with distance from nearest bayhead. Both large and small trees followed this pattern, suggesting that the invasion process is ongoing and has a long history. The likelihood of finding at least one bayhead invader is positively related to the area of the pond. Woody bayhead invasion of seasonal ponds depends upon the distribution of vegetation at the landscape level. Habitat destruction and fragmentation are likely to reduce the occurrence of this invasion by isolating both seasonal ponds and bayheads.

Leaf and fruit collections from the four known populations of the Maple-leaved oak, Quercus shumardii Buckl. var. acerifolia Palmer (Fagaceae), were analyzed for 47 qualitative and quantitative characters. Qualitative character states are identical within and among populations; means and ranges of variation for quantitative characters are very similar among populations although the ranges of variation within populations are often large. Data presented here adequately characterize leaves and fruits of this taxon to allow for reliable identification in the field and herbarium. Previously unpublished identifiers are also noted. The Maple-leaved oak is treated conservatively at the varietal level in this paper, pending further comparisons between it and the other taxa in the Quercus shumardii complex.

The Alabama canebrake pitcher plant, Sarracenia rubra ssp. alabamensis, is an endemic species found in just three counties of central Alabama. This study includes a census of this species, as well as an assessment of the viability of each population. Only eleven sites remain, ranging in size from 2 m² to 2,200 m². Numbers of individual plants at each site ranged from 4 to 2,241. There was an uneven distribution of individuals between sites, with 60% of the total occurring at just one site. Most sites were classified as seepage bogs with characteristic acid soils. Associated species included other typical wetland plants and three other kinds of carnivorous plants, and invasive woody plants were prevalent at most sites. Only three of the eleven sites were considered to contain viable populations. Threats to these sites included development, livestock grazing, mining, and the absence of fire. We conclude that S. rubra ssp. alabamensis requires immediate management action to maintain these dwindling populations.

This is the first report of Oplismenus hirtellus (L.) Beauv. ssp. undulatifolius (Ard.) U. Scholz for North America (Kartesz 1994 and pers. comm.). It was recently discovered by Edward Uebel in two Maryland localities. The first, in Patapsco Valley State Park, is a single population or ‘patch’ about 1.8 x 2.7 m in diameter; whereas the second location, approximately 6.4 km to the north, contains several small to large patches up to 15 m in diameter.

Even if you’ve read every book on North American orchids-and there must be dozens-you’ll find this book unique and exciting. Even if you’ve stomped through field, forest, and bog to photograph the rarest of the elusive native orchids, you’ll find a variant or a detail that you never saw before illustrated in this volume. Even if you have the attitude of a staunch conservationist and plant lover, you’ll find new perspective and appreciation for nature in this text.