As an adaptation to unpredictable light and pollination levels in the deciduous forest, clonality in early spring flowering plants enables continued population persistence but can have profound impacts on the population genetic structure. To gain a better understanding of clonal diversity in the common spring ephemeral herb Erythronium americanum (American Trout Lily) and its relationship to population size, five populations were examined using microsatellite markers. In general, levels of genetic diversity were low, with larger and more dense populations of E. americanum exhibiting less allelic diversity than smaller and less dense populations. Over half (68.56%) of sampled individuals overall were clones, with populations containing 2–21 clones and larger populations possessing the fewest number of clones. Several factors may contribute to these patterns, including geitonogamy, genetic drift, and intraspecific competition. The patterns of allelic diversity across the range indicate two distinct genetic clusters of E. americanum with northern and southern groups separated at the Ohio River valley.

The mint genus Dicerandra is the rarest of any plants in the southeastern USA, and the narrow endemic D. thinicola H.A. Mill. is restricted to one wild population on public land and a few unprotected populations on private lands. From 2001 to 2017, we studied ∼9,000 plants and 90,000 annual transitions in permanent plots in Florida scrub and roadsides to assess the health of this population and potential drivers of demographic change. Plant numbers have fluctuated widely, largely due to variably large pulses of winter seedling recruitment, but the overall trend has been upward, especially along sandy roadsides, in scrub gaps, and in chopped/burned scrub. Across the data set, annual survival (mean 67%) varied among habitats (being highest along roadsides) and among years (with decreased survival in some recent years). Nearly half of surviving vegetative plants advanced from vegetative to reproductive each year and most plants, once flowering, continued to flower each year. Growth in number of branches was consistently positive; only one-quarter of plants had reduced size each year. Relative growth rate was higher along roadsides than in other habitats. Reproductive output was lowest in scrub gaps and varied among years. Seedling recruitment was concentrated in winter months, varied widely among years, and was lower in the scrub matrix than in scrub gaps or roadsides. About half of seedlings died before their second year, the maximum observed life span was 13 yr, and fewer than 6% of plants survived 10 yr. Flowering began as early as age 2 (rarely as seedlings) and by age 4–7, 90% of surviving plants were reproductive. Land management (roller chopping and fire) in 2007 had profound effects on the population. Chopping killed 91% of plants and chopping followed by burning killed 100%. However, recruitment in these treated plots was 2.5–5.5 times higher in the 6 yr after treatments than in the 8 yr before treatments; no such differences were seen in untreated plots. Posttreatment plants grew faster and flowered earlier than other plants. Consequently, after several years, plant numbers in the treated areas had increased 4–8 times, whereas plant numbers in untreated areas changed little. This state-endangered plant is short-lived and depends heavily on disturbance (ideally fire) for recruitment and population growth. It is threatened not only by its narrow distribution but by insufficiently aggressive land management.

Molecular markers have shown a high level of genetic diversity in most extant populations of the federally endangered Lindera melissifolia (Walt.) Blume in the southeastern United States. However, it is unknown if diversity in adaptive traits exists. We quantified adaptive trait variation in 17 L. melissifolia genotypes by growing genets from two disjunct populations in the Lower Mississippi Alluvial Valley in a common-garden environment. We then examined genotype-environment interaction through introduction of a flooding treatment. Within a common-garden environment, variation in adaptive traits was affected by genotype. Stem height, stem diameter, leaf number, and stem architecture accounted for 56% of variation among genotypes, and an additional 23% of variation was attributed to differences in vegetative fecundity and foliar chlorophyll content. There was no divergence in plant morphology between disjunct populations. Plastic response to a winter flooding regime varied in magnitude and direction among male genotypes, and only in magnitude in female genotypes. A decrease in L. melissifolia population sizes would diminish genetic diversity, as well as adaptive trait variation, and may threaten long-term persistence of extant populations.

Allelopathy is a process by which a plant releases chemicals that inhibit competitors. Recent phytochemical studies have reported the presence of phenolic molecules in some species of Pilosocereus, which could be indicative of allelopathic effect. The aim of this study was to assess the allelopathic potential of the fruit pulp extract of Pilosocereus gounellei on the germination of seeds of Lactuca sativa and P. gounellei. We tested the effects of pulp extract at four different concentrations. We measured the osmotic potential of the extract at the different concentrations, in order to assess its effect on seed germination. The extract negatively affected the germination parameters of both species and effect was more significant at higher extract concentrations. The influence of the osmotic potential on the germination parameters was not significant for most of the studied parameters. We believe that our results are indicative that the fruit pulp extract of P. gounellei contains allelochemicals that delayed or inhibited seed germination of not only L. sativa, but also of seeds of their own species (autoallelopathy). Further studies are necessary to clarify the inhibition mechanisms, and how widespread the allelopathy is across other cactus species.

Palicourea is a Neotropical genus of predominantly shrubs and subshrubs, represented by more than 700 species, with its greatest diversity in South and Central America. The present study aims to describe and compare the leaf anatomy and micromorphology of six species occurring in the Atlantic Forest to determine which characteristics are most useful for taxonomic study and which are more useful for ecological investigation. Plant material was collected at Atlantic Forest sites in southeast Brazil. Samples preparation followed standard techniques for light and scanning electron microscopy and histochemical tests. The general characteristics observed for genus were absence of domatia, presence of unicellular trichomes on the abaxial surface, hypostomatic leaf blade with paracytic stomata, uniseriate epidermis with papillae, presence of idioblasts, and dorsiventral mesophyll. The results allowed us to segregate species by leaf structure and infer the affinity relationship among the studied species. This study showed the importance of leaf anatomy as a diagnostic tool for the six species of Palicourea; emphasizing characteristics that indicate infrageneric groups.

The leaves and ramicaules of 16 epiphytic species from the genera Acianthera, Anathallis, and Specklinia belonging to the subtribe Pleurothallidinae were analyzed anatomically in order to find useful traits for the distinction of genera and species. The present study reveals that the leaves of Pleurothallidinae species possess anatomical characteristics such as trichomes, vascular bundles, and idioblasts, which are valuable for distinguishing such genera. We also found that leaf characteristics, such as the shape of epidermal cells, margin type, cuticle ornamentation, hypodermis, and presence of idioblasts, in conjunction with characteristics of the ramicaule, such as cross-section shape and cell type of the external cortex, can be used to distinguish species. A key to the genera based on data is provided and some characteristics are discussed regarding epiphytism.

Five species of Inocybe from eastern North America are described as new: Inocybe carolinensis, Inocybe dulciolens, Inocybe friabilis, Inocybe glaucescens, and Inocybe vinaceobrunnea. Inocybe carolinensis is a new species in Inocybe sect. Inocybe; I. dulciolens and I. glaucescens are two new species in Inocybe sect. Lactiferae; I. friabilis is described as new in the Pseudosperma clade (Inocybe sect. Rimosae sensu stricto); and I. vinaceobrunnea is newly described for I. jurana sensu Hesler in the Inosperma clade (Inocybe sect. Rimosae sensu lato). At least four of the five species are endemic to regions of eastern North America based on current distribution data. ITS, 28S rDNA, rpb2, and rpb1 genes, in combination with morphological and ecological traits, are used to aid in species recognition. Phylogenetic trees, taxonomic descriptions, and illustrations are provided.