Persea borbonia and Persea palustris are two species in the Lauraceae family, native to the southeastern USA. Because of their similar morphologies, many authorities treat these two species as varieties of a more broadly defined group, Persea borbonia. Consequently, the species and communities associated with P. borbonia and P. palustris are not well defined. Extensive mortality has occurred in both species because of laurel wilt disease. Our objectives were to (a) determine whether P. borbonia and P. palustris are associated with different communities, (b) describe the communities and associated species in which P. borbonia and P. palustris occur, and (c) determine which communities support larger individuals of Persea spp. We analyzed data collected from 1988 through 2012 by the Carolina Vegetation Survey. To test differences among plant communities with natural growth of P. borbonia and P. palustris, we used ordination and analysis of similarities. We used cluster analyses and species-indicator analyses to group 388 plots into distinct communities. Results were verified by random forest analyses. We compared basal area of Persea spp. in each community with Kruskal-Wallis multiple comparisons. Persea borbonia and P. palustris communities were significantly different in species composition. Persea borbonia was limited almost exclusively to maritime coastal forests, whereas P. palustris had a larger geographical range, extending from near-coastal settings inland through the fall-line of the sandhills. The cluster and indicator species analyses identified eight unique groups, one for P. borbonia, and seven for P. palustris.

Soil diaspore banks are important temporal refuges for forest plants and, although fern spore banks are prevalent, they are understudied in relation to forest management practices. As urbanization increases, understanding the dynamics of spore bank resources in urban forests becomes increasingly important. Urban forests tend to have a greater propensity for species invasions and present challenges to plant species management not encountered in other managed forests. We studied the impacts of Lonicera maackii removal on fern assemblages aboveground and in diaspore banks in an urban forest. The diaspore bank assemblage had greater richness and abundance of ferns compared to the aboveground assemblage. Six years after management implementation, plots from which L. maackii was removed had fewer fern species and fewer ferns in the spore bank than paired control plots in which the shrub was not removed. Two nonnative ferns typical of residential ornamental plantings and with characteristics of potentially invasive species were also found in control plot spore bank assemblages. Environmental variables including pH and amount of leaf litter contributed to differences between spore bank fern assemblage structure in removal and control areas. These results indicate the need for further studies of fern diaspore banks in managed, urban eastern forests.

The genus Isoetes is known for morphological convergence and a relative paucity of useful gross morphological characters for identification. Thus, the chromosome complements of Isoetes spp. are key attributes for species delimitation. Like many other plant lineages, polyploidy and reticulate evolution are important drivers of speciation in Isoetes. In the southeastern US Isoetes flora, polyploidy is common. We used a rapid DNA flow cytometry protocol to generate C values for four diploid, one tetraploid, and one hexaploid Isoetes species and conducted preliminary cytological investigations of two communities of Isoetes. Our work showed noteworthy variation in diploid Isoetes 1C values (1.39 to 3.32), including the smallest 1C value reported for the genus, Isoetes melanopoda ssp. silvatica. The hexaploid species, Isoetes microvela had the highest 1C value (4.21), and the tetraploid species evaluated had an intermediate 1C value (3.37). However, based on the variation in diploid 1C values measured, a simple 2×, 4×, 6× ratio of C values was not apparent for diploids, tetraploids, and hexaploids, respectively. All Isoetes taxa measured had significantly different 1C values and homogenous C values were observed in two communities of Isoetes (n = 24). These results indicate that DNA flow cytometry may prove a useful tool for routine Isoetes species identification, systematic work, and population-level surveys of Isoetes ploidy level.

Cyathium morphology of Euphorbia spathulata from three populations in central Virginia was studied from early developmental stages through nominal anthesis, defined by exposure of the cyathium to the external environment by divergence of paired subtending cyathophylls. Observations were made via dissecting microscope, compound light microscope sections, and scanning electron microscopy. The plants studied revealed a consistent pattern of asynchronous stamen and pollen development as well as a series of predictable changes in style and stigma orientation. Initially, styles and stigmas of pistillate flowers maintain a near-axial (erect) position. Later, when still enclosed by subtending cyathophylls, styles reflex, placing stigmas near early developing anthers shedding pollen. Pollen grains observed on stigmas at this stage indicate cleistogamous pollination. Eventually, paired cyathophylls diverge, exposing the cyathium to the external environment; at this stage, styles and stigmas assume an ascendant position as late-maturing anthers shed pollen, a configuration conducive to chasmogamous pollination. These observations indicate that a succession of cleistogamy and chasmogamy characterize the reproductive process of each cyathium of E. spathulata, at least in the populations studied.

Regional (climate/soils) and local (aspect) physiography determine plant community composition. However, changes in initial floristic composition after a disturbance may be severe enough to alter the successional trajectory predicted by physiography. We addressed the question of which is more important, disturbance or physiography, in determining vegetation composition and the consequent successional trajectory. We evaluated understory vegetation of forest communities exposed to four disturbance types (control, single burn, diameter-limit cut, and first-removal shelterwood) 2–5 yr postdisturbance. Study sites were located within each disturbance type on northeast and southwest aspects within the Appalachian Plateau and the Ridge and Valley provinces. Vegetation composition was analyzed with nonmetric-multidimensional scaling, two-way nonparametric multivariate ANOVA, and indicator species analysis. The relationship between disturbance and key environmental variables, including canopy opening and soil fertility, was analyzed with generalized linear mixed models. There were 363 species in our study area. Composition differed by province and aspect. Composition also differed by disturbance but with a significant province interaction. Although physiography was more important, some species served as disturbance indicators that differed by disturbance type with two possible outcomes. First, expected successional trajectories (as defined by the regional and local environmental filters) may deviate toward recovery of native species (e.g., Epigaea repens) that benefit from low-level disturbance (as defined by fire as a filter). Second, successional trajectories after a relatively severe disturbance (as defined by shelterwood harvest as a filter) may deviate toward systems that are vulnerable to invasion by exotics or dominant native species.

Apios priceana (Fabaceae) is a rare herbaceous perennial vine. Seed collection for ex situ conservation is difficult because seed production is sporadic. We investigated propagation by cuttings of A. priceana at Redstone Arsenal, Alabama. Two experimental factors were investigated: donor plant size (small vs. large) and month of cutting (May vs. June 2013). We also documented impact of cutting collection on donor plants by recording size and reproductive variables from both cut and uncut (control) plants. About one-third of cuttings formed tubers by May 2014; success did not differ due to donor plant size or month of cutting. However, May cuttings produced two-fold more tubers and had five-fold greater total tuber mass. Large donor plants grew more, and produced significantly more inflorescences and legumes than small donors. Cutting treatment alone did not significantly affect any donor plant variable, showing that donor plants recovered quickly after cuttings were taken. Significant interactions (for stem diameter and inflorescence production of donor plants) suggested that cutting more greatly stimulated regrowth of large plants cut in June. We conclude that propagation by cuttings can rapidly produce plants of this species for ex situ conservation, but there are trade-offs in outcomes. Cuttings taken in May have an advantage for tuber production (producing more tubers and greater tuber mass), whereas cuttings taken in June affect donor plants less (although this effect was modest). Overall, propagation by cuttings is a useful technique for this rare species as it produces new plants yet minimally impacts wild populations.

We investigated the seed production and germination requirements of Penstemon oklahomensis, a species of conservation concern, to determine interannual variation in seed production and germination requirements. Mature seed capsules were collected and seed numbers counted in two successive years to assess interannual variation in seed production. A significant difference in number of seeds produced was found between collection years. Germination trials were conducted using the seed collected and subjected to three stratification treatments in two soil types. Seeds held over from the first collection year were also germinated to investigate viability loss a year after collection. Survival analysis was used to estimate the probability of seed germination under the treatment conditions. Germination probability was highest for seeds that underwent a cold stratification period of 60 days if sown the same year as they were collected, regardless of soil type used. Seeds held over a year had higher germination probability after a 30-day cold stratification period, but the probability was lower than the same treatment when the seeds were sown during the year collected. Seed production and germination requirements for P. oklahomensis are similar to other species of Penstemon, both in the Intermountain West and east of the Mississippi River.

Coastal ecosystems face numerous well-documented threats that pose significant risk of reduction in the ability of these ecosystems to persevere. Although coastal disturbance processes related to maritime exposure are relatively well known, the past and potential impacts of fire in these ecosystems have not been well studied. Because fire plays such an important role in so many other southeastern ecosystems, and because the areal extent of coastal strand ecosystems has been much reduced, it is important to resolve the role of fire for management of these threatened communities. In 2014, prescribed fire management was undertaken in a protected and relatively intact, 55-ha remnant section of coastal strand in the Guana Tolomato National Estuarine Research Reserve (GTMNERR) adjacent to the Atlantic Ocean in northeast Florida, USA. The fire history for this area was unknown. We compared burned samples to unburned samples to test whether there were differences in patterns of vegetative response to this fire management action. In backdune sites, we found significant dissimilarities in plant community biodiversity indicators between burned and unburned samples, whereas vegetative cover changed significantly in both foredune and backdune sites. We include a review of successional patterns and fire effects for similar sites in the region for comparison, which provisionally suggests a 4–20-yr fire return interval. We conclude that fire management for the backdune component of the coastal strand is an important strategy for this ecosystem to avert succession to maritime hammock.

Twenty-seven species, new to the flora of Georgia, are reported here and validated by cited voucher specimens at the University of Georgia (GA) and Valdosta State University (VSC) herbaria, the two largest herbaria in the state. Reassessment and comparison of these collections data have been greatly facilitated by specimen digitization efforts, especially those fostered among herbaria by the GA–VSC Herbaria Collaborative and by the Southeast Regional Network of Expertise and Collections (SERNEC). Four species (Chelone lyonii, Prunus hortulana, Sporobolus arcuatus, and Symphyotrichum simmondsii) are likely native to Georgia and represent range extensions from nearby states. Chelone lyonii and Sporobolus arcuatus are rare and state-ranked critically imperiled (S1) by the Georgia Department of Natural Resources. The 23 exotic species are more or less naturalized or have potential to naturalize in the state. These nonnatives are escapes from cultivation (15 species) or weedy plants (eight species) that are widespread elsewhere and not typically cultivated. Four species (Cleome monophylla, Lobelia pedunculata, Quercus myrsinifolia, and Sedum emarginatum) are putative first records for the flora of North America, at least as occasional escapes.

Mountain stewartia (Stewartia ovata) is the only member of the family Theaceae endemic to Tennessee. Apart from its physical description and rarity, little is known about this woody understory species. Accounts of stewartia populations and range descriptions are longstanding, but microsite descriptions are limited in detail. We quantified microsites supporting populations of stewartia across East Tennessee as a first step in determining whether stewartia is rare because of rare or altered habitat, limited sexual reproduction, poor dispersal, or a combination of these factors. Five populations of stewartia averaging 7.40 ± 1.08 stems per population were inventoried across four East Tennessee counties. Soils on all sites were strongly acidic, highly permeable, well-drained, cobbly loams associated with steep slopes and higher elevations and were low in phosphorus, potassium, calcium, and magnesium. A dense overstory comprised of sourwood (Oxydendrum arboreum), eastern hemlock (Tsuga canadensis), white oak (Quercus alba), eastern white pine (Pinus strobus), red maple (Acer rubrum), and mockernut hickory (Carya tomentosa) resulted in 7.05% ± 1.41% of full photosynthetically active radiation (PAR). The midstory and understory were dominated by eastern white pine, red maple, and eastern hemlock. Quantification of stand-level conditions in extant stewartia populations suggested similarities in soil pH, nutrient levels, drainage, overstory composition and structure, and PAR levels. Certain conditions in stewartia sites were unique in the region, suggesting that habitat may limit populations along with other factors. Further investigations of stewartia reproductive ecology, dispersal, and habitat requirements will be key to conserving this species.

Old-growth forests provide unique insight into historical compositions of forests in the eastern United States. Plots established within a mixed forest community within Marshall Forest in Rome, Georgia, in 1960 (and remeasured in 1989) were reassessed to determine changes in forest composition. The community has experienced approximately 10% increase in basal area since the previous measurement period. However, changes in species importance have occurred. Chestnut oak (Quercus montana), mockernut hickory (Carya tomentosa), white oak (Quercus alba), and flowering dogwood (Cornus florida) have all decreased in importance, while pignut hickory (Carya glabra), winged elm (Ulmus alata), yellow poplar (Liriodendron tulipifera), and red maple (Acer rubrum) have all increased in importance. Additionally, there are no Pinus spp. saplings in the study area, indicating seedlings are not being recruited into the midstory. These changes indicate continued succession to a composition increasingly dominated by shade-tolerant species. The mixed forest community appears to be transitioning to an oak-hickory community. The assessment of late successional dynamics may help managers of similar forests to determine the best plan of action if they desire to maintain a mixed forest ecosystem.

Large expanses of loess hill prairie were once common along the bluffs of the Mississippi and Illinois rivers of Illinois. These communities occur in forest openings on thick loess deposits overlying bedrock and frequently have expanses of exposed limestone at their margins (glades). Warm season, clump-forming grasses dominate the herbaceous vegetation along with a mixture of prairie and open forest species. Miles Hill Prairie, Monroe County, Illinois is located about 20 km west of Waterloo in the Northern Section of the Ozark Natural Division. Within the prairie, 148 vascular plant species were recorded with 40 species found in the survey plots. Schizachyrium scoparium dominated followed by Andropogon gerardii, Solidago speciosa, Sorghastrum nutans, and Bouteloua curtipendula. Common forbs include Pycnanthemum pilosum, Symphotrichum patens, and Symphotrichum oolentangiense with Cornus drummondii the most abundant shrub, and Torilis japonica the only exotic species in plots. This is a high-quality loess hill prairie that is well maintained by prescribed fire and brush removal. Most species encountered were common to loess hill prairies, with the 19 exotic species being rare and mostly restricted to prairie edges.