Plant life history traits like clonal growth and dioecy can complicate endangered species conservation because of the potential for remnant populations to contain few genetically different individuals or a single sex. In this study, we used 11 microsatellite (SSR) markers to characterize fine-scale genetic structure of the endangered dioecious perennial Lindera melissifolia (pondberry) growing in seasonally isolated wetlands across the southern Atlantic Coastal Plain. We found fine-scale genetic structures consistent with extensive clonal growth in all sites. Of the 508 stems sampled across 11 sites, we found 67 genetic individuals (genets), of which 94% were site specific and 39% were represented by a single stem. Individual sites contained from 1 to 16 genets. Spatial genetic analyses showed limited intermingling among different genets within sites, which is consistent with a phalanx clonal growth form. Nine of the eleven sites had biased sex ratios, with six male and three female biased sites. Given our observations of extensive clonal growth, few genetic individuals, and biased sex ratios, we conclude that simple stem counts of this clonal perennial dioecious shrub will grossly overestimate the number of genetic individuals in these remnant southern Atlantic Coastal Plain sites. In order to promote self-sustaining sexually reproducing pondberry populations, as outlined in the pondberry recovery plan, natural areas managers may want to consider introducing unrelated and underrepresented gender plants into sites with few genets or biased sex ratios.

Climate change is of increasing concern in coastal forests where rising sea levels could lead to dramatic shifts in ecosystem composition. To investigate how inundation may impact coastal ecosystems, we examined the sensitivity of Quercus virginiana Mill., a dominant tree in the southeastern U.S., to increased soil salinity and examined whether high salinity could increase its susceptibility to freezing damage (−10 °C). In a greenhouse, we examined the effect of three salt treatments (0–6 ppt) on acorn development and sapling physiology. We examined samples collected from two populations: inland Florida (FL) and coastal North Carolina (NC). We found that higher salt concentrations did not affect acorn germination, but did retard emergence. In the sapling stage, high salinity was more detrimental to plants from the FL population, causing greater declines in photosynthetic rates, water use efficiency, and dark quantum yield. FL plants also demonstrated a lower freezing tolerance than NC plants but freezing temperatures did not exacerbate effects of salt stress. Our data demonstrate important population-level differences in the salt and freezing tolerance of Q. virginiana. Since salt tolerance is important to the recruitment, growth, and survival of coastal Quercus species, this research can help with future conservation and management of this important species.

Seasonally flooded wetlands are periodically drained due to dry-season precipitation patterns. In the dry season, soil moisture can decrease to a level where wetland vegetation communities are subjected to drought stress. To understand the effects of drought conditions on the structure of seasonal wetland communities, we conducted a post-flooding reciprocal transplant experiment among three grass species across a soil moisture availability gradient at Archbold Biological Station, Florida, USA. We also manipulated the intensity of competition. We found that Cutthroat, the most upland species, responded physiologically to low soil moisture via root growth and leaf tissue moisture content, while the two flood-adapted species (Maidencane, Blue Maidencane), modulated growth and exhibited a dieback-resprout “drought deciduous” mechanism. These differential phenotypic responses, and not competition, were responsible for growth patterns in Florida seasonal wetlands in drought conditions.

Crocanthemum dumosum is a globally rare plant endemic to the northeastern United States. The species is considered vulnerable to extinction due to its limited range and low population numbers. This taxon is often confused with its wide spread relative C. canadense, and its recognition as a separate species is often questioned. Within the range of C. dumosum there are three other species that belong to the genus Crocanthemum. In this study, we used AFLP markers to evaluate genetic variations among populations of the four Crocanthemum species found in the southern New England region with special focus on the genetic relationship between C. dumosum and C. canadense. The AFLP data showed that the four Crocanthemum taxa in the southern New England region had high among population and low within population genetic diversity. UPGMA clustering and principle coordinate analysis clearly separated C. bicknellii and C. propinquum from each other and from C. dumosum and C.canadense, indicating significant differences in their genomes and further supporting their distinction as separate species. However, C. dumosum nested within the same cluster as C. canadense which suggest their genomes are very similar. Based on the results from our molecular data and that of the previous morphological analyses, we find insufficient evidence to support the distinctiveness of C. dumosum from C. canadense and we recommend that it be considered as a subspecific variant of C. canadense. Furthermore, we suggest that these findings be taken into consideration during review of C. dumosum conservation status.

Conservation of a threatened species requires knowledge of the factors that affect its recruitment, survival, and reproduction. We conducted a long-term study on the demography of Paronychia chartacea ssp. chartacea, a short-lived, gynodioecious Florida rosemary scrub endemic. Specifically, we assessed the effects of habitat (rosemary scrub vs. roadsides), time-since-fire, microhabitat, and rainfall on recruitment, survival, flowering, and seed production. In addition, in a shorter-term study, we assessed the effects of habitat, time-since-fire, and gender on flower and seed production. Overall, approximately one-third of individuals survived more than one year and individuals most often flowered twice indicating that P. chartacea ssp. chartacea is an iteroparous, short-lived perennial, which is in contrast to its disjunct conspecific, the annual P. chartacea ssp. minima. Recruitment was higher in roadsides, but seed production was higher in rosemary scrub. Within rosemary scrub, recruitment was highest at intermediate times-since-fire and in the center of large gaps, the microhabitat with the greatest amount of bare sand. Median lifespan was longest in long unburned sites, suggesting that P. chartacea ssp. chartacea is able to persist despite litter accumulation and competition from shrubs. Rainfall had a positive effect on annual survival, but did not affect seedling recruitment. Females produced more seeds than hermaphrodites, indicating that females contribute more to population persistence. Our study suggests P. chartacea ssp. chartacea populations will persist under the 15–40 year fire return interval characteristic of regularly burned Florida rosemary scrub, but may not persist in roadsides if greater recruitment does not balance shorter lifespans.

Seedling morphology is relevant in classification, taxonomy, and vegetation studies to understand plant life cycles, germination succession and requirements, and developmental progression. However, most morphological studies of seedlings lack analysis of organ anatomy, impeding the comprehension of series of development and establishment in a particular environment. Here, we have taken a traditional anatomical approach to examine the stages of seedling development in Epiphyllum phyllanthus, a holo-epiphytic cactus of tribe Hylocereeae. The goals were 1) to offer a comprehensive description of growth series in E. phyllanthus seedlings based on morphological and anatomical analysis and 2) to examine the initial growth phases in the life cycle of this species to identify organ development and understand their adaptive significance in relation to seedling establishment. Our results include descriptions of seed morphology, embryonic features, and seedling vascularization pattern in the root, hypocotyl, cotyledons, and epicotyl. The morphological and developmental patterns in E. phyllanthus seedlings have potential phylogenetic and ontogenetic implications in the Cactaceae. Characters such as the presence of mucilage on the seed coat, the lack of seed operculum, and large cotyledons in E. phyllanthus are comparable to basal cacti, but the root anatomy is more similar to columnar relatives. At the familial level, there is an apparent trend in decreasing number of phloem and xylem poles in the stele of primary root, correlated with degree of specialization and advanced phylogenetic position: tetrarch to septarch–octarch in basal lineages, tetrarch Cereus-type in columnar species, to the diarch vascular system in Rhipsalideae and some species with cylindric/globose stem.

Wiliwili (Erythrina sandwicensis), an endemic Hawaiian dry forest tree species, is threatened by an invasive gall-forming wasp (Quadrastichus erythrinae) first detected in Hawai‘i in 2005. Eurytoma erythrinae, a predator of Q. erythrinae from Tanzania, was selected as a biological control agent and was released at sites throughout the Hawaiian Islands. To assess the effectiveness of this biocontrol release, we measured the extent of damage attributable to Q. erythrinae wasps in 124 E. sandwicensis trees at the Waikoloa Village Dry Forest Recovery Project before (January, 2009) and after (January, 2011) the release of the parasitoid wasp at this site. Because host spatial distribution has important consequences for the establishment and success of natural enemies such as parasitoids, we took a spatially explicit approach to account for the potential spatial heterogeneity in E. sandwicensis. We observed an increase in galling damage across the population and 21 trees became completely defoliated between the two survey years. The distribution of E. sandwicensis across the landscape was highly clumped and tree-level change in galling damage showed a strong spatial signal. Erythrina sandwicensis recovery was non-random with respect to landscape indicating that individual response to the biocontrol agent and exogenous factors (e.g., drought) may have strong interactions with the invasion and persistence of the pest Q. erythrinae.

A new species from Colombia, Scaphyglottis dariensis, is described and illustrated. A key to Scaphyglottis species found in the Darién Gap is presented.

Trindade is an oceanic archipelago situated roughly 1140 km east of Espírito Santo State, Brazil. It reaches an altitude of 620 m a.s.l. and covers approximately 10 km². Less than 5% of the island is covered by forest and approximately 60% by herbaceous vegetation. Several new and endemic plant taxa were described in the 1960's, and some of these had not been registered since then. From 1700 to 2005 the Island suffered from large populations of feral mammals, especially goats. Within the framework of a vegetation regeneration survey following goal eradication, our specific objective was to search for the putatively extinct species. Six field trips were undertaken from 2009 to 2012, resulting in more than six months of effective search time on the Island. Two of the three putatively extinct species were rediscovered, both ferns: Asplenium beckeri and Elaphoglossum beckeri. Peperomia beckeri remains known only from the holotype. Most likely the rediscovered species regenerated through the spore bank. Due to the elimination of goats and to conservational efforts, and in light of the observed expansion of the populations, the reestablishment of these rediscovered species on Trindade Island seems guaranteed.

Fourteen species of Phallales known to occur in the tropical region of the Atlantic Forest in Brazil are discussed. New records are reported for the country (Laternea dringii), Southeastern Brazil (Abrachium floriforme), Northeastern Brazil (Clathrus columnatus and Mutinus argentinus), and the states of Paraíba (M. caninus and Staheliomyces cinctus), Rio de Janeiro and Espírito Santo (Phallus indusiatus). Descriptions and illustrations of the new records and a key to the phalloid fungi from this region are presented.