Over the past several decades, naturally occurring populations of Fraser fir (Abies fraseri) in the Black Mountains of North Carolina have been heavily impacted by both direct and indirect anthropogenic disturbances, including logging and logging-associated fires, and high mortality rates due to the balsam woolly adelgid (Adelges piceae) (BWA). The decline in Fraser fir is worrisome because it serves as a foundation species of the spruce-fir forests of the Southern Appalachian Mountains. Our objectives for this research were to: 1) characterize the current status of Fraser fir trees with respect to potential population decline, as identified by the regeneration-mortality hypothesis, by using stand structure and infestation levels, 2) determine the influence of slope, elevation, aspect, and disturbance history on stand structure, mortality, and BWA infestation level, and 3) examine broad trends of Fraser fir cover change caused by BWA over a 60 year period by using repeat aerial photography. We conducted detailed field surveys of Fraser fir trees throughout the Black Mountains using 44 circular plots. Analysis of repeat aerial and ground photographs revealed a decline in Fraser fir cover >60% from 1954 to 1988, followed by regeneration from 1988 to 2006. Our results indicate that Fraser fir stands at higher elevations are currently in a state of recovery, whereas Fraser fir stands at lower elevations have the potential to become increasingly susceptible to BWA-induced mortality in the future. Our results call attention to the significant impact of direct and indirect anthropogenic disturbance upon Fraser fir stand structure, but also provide evidence for the ability of an imperiled ecosystem to recover from such activity.

The largest Maryland population of the federally threatened tidal freshwater wetlands legume, Aeschynomene virginica (Sensitive Joint-vetch), is comprised of two subpopulations in the Manokin River watershed. To provide baseline data fundamental to understanding annual fluctuations and long-term trends, annual censuses began in 1991 and 1994 for Taylor Branch and Manokin River subpopulations, respectively, and continued through 2009. In addition, distributional limits, phenology, average plant height, associated plant species, and muskrat activity were recorded to better understand plant and habitat characteristics. Large annual fluctuations in size were common to both subpopulations. The Manokin River subpopulation (2 km in extent) averaged 1,867 ± 268 plants (n  =  16), ranged from 715–4,394 plants, and inhabited marshes (56%) and banks (44%). Subpopulation size increased significantly during the survey period. June rainfall may have contributed to a tripling in subpopulation size from 2005 to 2009, but a significant increase from 1994–2006 was related to some undetermined environmental factor. The Taylor Branch subpopulation (0.6 km in extent) averaged 400 ± 122 plants (n  =  18), ranged from 42–1,797 plants, occurred almost solely in marshes, and did not change significantly in size over the study period. Seed germination occurred in late April, shoot growth through July, and flowering and fruiting peaked by mid-August and early October, respectively. Muskrat effects were negligible for both subpopulations. Although continued subpopulation monitoring is important, sediment accretion and wetland hydrology studies are needed to predict long-term viability of A. virginica in the Manokin River watershed.

Arabidopsis lyrata ssp. lyrata is widespread but edaphically restricted, which suggests that the dispersal ability and level of genetic exchange among populations might be limited. We assessed levels of genetic diversity and population differentiation within and among six A. lyrata ssp. lyrata populations from along the eastern seaboard of the United States by examining variation at nine microsatellite loci among 233 individuals. These data were also evaluated to assess any relationship between geographic and genetic distance and correlation of genetic diversity with population size. Measures of genetic diversity across all 9 microsatellite loci were high in most populations. Genetic diversity, as measured by number of alleles, was generally higher in the Maryland and New York populations, as compared with the southern most sampled populations in Virginia. Genetic differentiation among regions was highly significant and large (F_ST  =  0.47). This was supported by several analyses, suggesting that there is little gene flow among the regions sampled. There was a strong positive correlation between geographic and genetic distance, which is indicative of the pattern of isolation-by-distance. Population size correlated with the number of alleles within populations, supporting population genetic theory that larger populations harbor greater genetic diversity. Wright's F_ST and genetic structure analysis also provided evidence of genetic partitioning at small (<100 m) geographic distances between two areas sampled within one locality. These results indicate that the largest proportion of variation was explained by within population differences and may have implications for the conservation of this widespread but fragmented taxon.

All orchids require free-living, mycorrhizal fungi to complete their life cycles in nature and consequently, orchid conservation must take into account both organisms. In light of climate change now underway, orchids and other plants must be capable of migrating to higher latitudes, either on their own or with human intervention ( = assisted migration). In this paper, we describe the symbiotic germination of a common terrestrial orchid, Habenaria repens, in situ using seeds from a southern ecotype (Florida) placed at latitudes at and above the species' current natural range. To recover fungi in situ, 500 nylon packets containing 25,000–50,000 seeds were buried at 5 field sites within the Atlantic coastal plain in North Carolina, Maryland, and Virginia. After ca. 5 months, a total of 10 leafless seedlings (protocorms) were recovered from two North Carolina sites, one harboring an extant H. repens population, the other an extirpated population. These protocorms yielded mycorrhizal fungi assignable to the anamorphic genus Epulorhiza. The physiological significance of each isolate was confirmed after H. repens seeds germinated in vitro following fungal inoculation ( = symbiotic germination). This study demonstrates that seeds of H. repens from a southern ecotype (Florida) are indeed capable of germinating at higher latitudes where fungi already persist. Consequently, the mycotrophic demands of orchids like H. repens might be met by assisted migration involving seed release alone.

Disturbance regimes of many hardwood forests of the eastern United States in the complex stage of development are characterized by localized canopy disturbance events that change fine-scale biophysical conditions. Recently, research has demonstrated the importance of gap-scale disturbance processes in secondary hardwood stands of the southern Appalachian Highlands. However, information on canopy disturbance patterns during early developmental stages is required from the broader geographic region for a comprehensive understanding of stand dynamics. The goal of this study was to reconstruct canopy disturbance history for mixed hardwood stands on the Highland Rim of Alabama to elucidate disturbance patterns during early development. We analyzed radial growth from 46 Quercus individuals to reconstruct canopy disturbance history. The majority (67%) of the trees analyzed exhibited release events. In total, 42 releases were detected and some trees experienced multiple events. Of these releases, 28 (67%) were classed as minor and 14 (33%) were classed as major. Mean release duration was 4.00 years ± 0.21 (SE) and the longest release was sustained for eight years. Based on mean release duration, we speculate that most of the canopy gaps were filled by lateral crown expansion rather than subcanopy height growth. We did not document any forest-wide disturbance events; a pattern that may be a regional phenomenon or may be related to forest age. Canopy disturbances became common after ca. 40 years of development. We propose that the frequency of canopy gaps will decrease and the size and magnitude of individual gaps will increase as the stands mature.

The vascular flora of Crenshaw County, Alabama, was surveyed from 1987 to 2010. A total of 1171 taxa (species and hybrids) in 565 genera from 150 families are reported. Twenty-five taxa represented by herbarium specimens from Crenshaw County were not re-collected during this study. The Inventory List of Rare, Threatened and Endangered Plants, Animals and Natural Communities of Alabama as compiled by the Alabama Natural Heritage Program contains 23 of the species collected. Approximately 18 percent of the flora (213 species), are considered non-indigenous. Families with the largest number of taxa were Asteraceae (158), Poaceae (135), Fabaceae (87), Cyperaceae (61), Rosaceae (35) and Liliaceae (31).

Galax urceolata (Diapensiaceae) is a common evergreen herb of southern Appalachian forests. During the fall and winter, leaves of plants in high light produce substantial amounts of anthocyanins. Oddly, rhizomes in these plants also accumulate anthocyanins. The purpose of this observational study was to identify seasonal trends in anthocyanin production in above- and below-ground tissues of Galax. We measured anthocyanins and chlorophyll in Galax using standard extraction and spectrophotometric procedures from plants in sun-exposed and shaded locations; one population at Mount Jefferson State Natural Area in fall 2007 and two at Grandfather Mountain in fall/winter 2008–09. Rhizome carbohydrates (soluble sugars and starch) were measured from the Grandfather populations using high performance liquid chromatography. We found significantly more anthocyanins in leaves and rhizomes of plants from sun-exposed locations compared to plants from shaded locations, but no differences in carbohydrate concentrations. Starch levels declined significantly through the fall/winter of 2008–09, while soluble sugars, such as sucrose, raffinose, and fructose, increased. Rhizomal anthocyanins were distributed throughout the entire cross-section except for the vascular tissues, whereas in petioles and leaves, they were restricted to the epidermal or subepidermal layers. Rhizomal anthocyanins often concentrated around lateral roots as they penetrated the cortex. These results contradict the paradigm that light is always required for anthocyanin production, and suggest the possibility of some form of communication between leaves and rhizomes with respect to anthocyanin content, although the nature of that signal is unknown. At this time, the adaptive significance of below-ground anthocyanins in Galax remains unresolved.

Among herbaceous species of Hypericum with surficially glandular-punctate leaves and quadrate, narrowly winged stems, the five taxa of the “Hypericum denticulatum complex” of southeastern United States have in common petals that are strongly inequilateral, orange-yellow, ca. 1 cm long and 0.5 cm wide; stamens numerous (50–80); and styles comparatively long (2–4 mm). Three of the species are obligate wetland plants: H. denticulatum, H. harperi, and H. erythreae. The last-named, until now wrongly synonymized, is a species of the Atlantic Coastal Plain of southeastern Georgia and, historically, southern South Carolina. It resembles the mostly more northern H. denticulatum in having appressed or ascending leaves that are shorter than their internodes and in growing in boggy habitats, but is a taller plant that also differs by its notably sparse leaves that are distinctly reduced upward and on average proportionately narrower. The remaining two species are obligate upland plants: H. virgatum and H. radfordiorum sp. nov., the latter endemic to granite outcrops in or near the Brushy Mountains (inner Piedmont of North Carolina). It is like H. virgatum in having upper leaf surfaces much less conspicuously glandular-punctate than the lower, but in H. radfordiorum the leaves average longer and more acuminate, the stems are distinctly glandular-punctate, and many of the upper leaf axils bear flowering branches with leaves longer than their internodes.

Proposed by Linnaeus in 1753, Phlox ovata was a name of long-standing use until Reveal et al. established that an illustration cited in the Linnaean protologue and designated as the type of the species by a later monographer was based on a species from a different family, seemingly rendering P. ovata L. invalid and making P. latifolia Michx. the proper name. The issue was processed through a series of taxonomic papers that resolved the typification issue and ultimately ruled in favor of retaining P. ovata, but floristic and ecological workers have mostly used P. latifolia for this species since 1982. The correct name for the Allegheny phlox is Phlox ovata.

Magnolia virginiana, the type species of genus Magnolia, is a native American species belonging to section Magnolia. To better understand intraspecific taxonomy of Magnolia virginiana, we conducted molecular phylogenetic analysis based on sequences of cpDNA. Fresh leaves were collected from 28 populations (a total of 133 individuals) covering the entire distribution of the species, including the recently discovered Cuban population, and sequences of seven non-coding regions of the cpDNA were determined (ca. 5,000 bp). Based on nucleotide substitutions, ten haplotypes were recognized in M. virginiana. Phylogenetic analysis of the data matrix clearly indicated that populations of M. virginiana were divided into two major groups—one in the north and one across the south—which are essentially concordant with the morphological classification. Five nucleotide substitutions were found between them. Within the southern group, one common haplotype widely distributed, and populations of Texas (and adjacent areas) and western Tennessee showed a unique haplotype with an additional substitution(s), respectively. Less common haplotypes were found in Florida. The haplotype of the Cuban population was the same as the common haplotype of the southern group.