The Holston Army Ammunition Plant in the Ridge and Valley physiographic province of Hawkins County, Tennessee, comprises 2,420 ha encompassing 11 river kilometers of the Holston River and rising to the crest of Holston River Mountain. The extreme physiographic diversity includes riparian and bottomland areas, wetlands, grasslands, calcareous knobs, karst, and mountain slopes, with soils varying from acidic to neutral and from fine to coarse grained. Plant communities vary from largely intact natural communities to highly impacted open areas. The vascular flora of the site was composed of 1,047 species and subspecific taxa distributed in 140 plant families and including 458 county records and 207 exotics. The four most diverse plant families were the Asteraceae (131 taxa), Poaceae (126 taxa), Cyperaceae (87 taxa), and Fabaceae (51 taxa). The number of taxa in the four largest plant families far exceeded the number predicted by species-area plots. Eleven species are state-listed; two species were new to Tennessee. Noteworthy plant communities were associated with old growth Quercus montana, forested mid-slope plateaus, and grasslands dominated by native grasses and rushes. Many taxa had geographic affinities to areas to the south and west and fewer had affinities to the north.

Cercidiphyllum japonicum (katsura) is a dioecious tree native to China and Japan. Although imperiled in parts of its natural distribution, the species has become quite common as a cultivated tree in temperate North America. The species is noted as occasionally escaping cultivation in the eastern United States, but few records of established incursions (and the conditions under which they might recruit) exist in the literature. We here report an incursion of C. japonicum in central Pennsylvania, along with notes on seedling recruitment on the Bucknell University campus.

The focus of this study was on obtaining DNA sequence information from selected rare plant species of Tennessee and their close relatives for the nuclear ribosomal ITS region, which is widely used for molecular barcoding. New sequence data was obtained for 71 species from 18 genera. The ITS region provided a good molecular barcode for nine of the genera. For the other genera, the results suggested that the ITS region would be uninformative, problematic, or require detailed analysis for application. For the orchid genus Platanthera, data from the ITS marker allowed unambiguous identification of vegetative plants of the federally listed P. integrilabia, which will help make efficient use of resources for conservation of the species. For the aquatic genus Potamogeton, the ITS data suggested the presence of unsuspected interspecific hybridization involving the rare species P. tennesseensis which showed the need for further investigation. The sequencing results provided validation of the separation of Lobelia gattingeri as distinct from L. appendiculata. The results of the study expanded the database of DNA sequences for rare plants of Tennessee and also highlighted the need for further study of the flora of the state and of the southeastern United States.

Eastern hemlock (Tsuga canadensis) is projected to experience shifts in suitable habitat distribution in response to climate change. Models predict the southern boundary of eastern hemlock will remain geographically stable, but that eastern hemlock will decline in dominance and abundance along the boundary. In 2003 and 2013, 10 disjunct eastern hemlock stands on the southernmost portion of the Cumberland Plateau in Alabama were surveyed to characterize the vertical structure and diameter distributions of eastern hemlock. This work represents the third survey over 20 years and provides more complete insight into the stand dynamics of these disjunct stands. No trends were common among all stands, but there was a general decrease in the number of canopy eastern hemlock from 2013 to 2023. Despite the loss of canopy dominance, the majority of stands experienced an increase in the number of stems in the larger diameter classes. We expect these stands to remain viable and predict no shift in the southern range limit of the species. If, however, climate change effects begin to manifest in the stand structure or a severe disturbance occurs, eastern hemlock may lose dominance and be unable to regenerate. In 2021, an EF1 tornado obliterated one stand, and removed all canopy stems from another. Although the hemlock woolly adelgid (Adelges tsugae) is perhaps the most well-known threat to eastern hemlock, non-species specific disturbances have the potential to be equally as devastating to these disjunct populations.

Vaccinium sect. Cyanococcus contains 10–20 species native to the eastern United States. Most workers agree that Vaccinium elliottii is a distinct species of sect. Cyanococcus, although sometimes it has been relegated to synonymy under V. corymbosum. As far as we are aware, the type of V. elliottii has never been clarified. A lectotype is designated here from a collection of A.W. Chapman. A morphological description of the species is provided to further aid in the application of the name.

Plant communities of aquatic ecosystems have outsized effects on the system structure and function. In Mississippi, aquatic plant communities are often poorly described, particularly in small lakes. In June 2024, the plant community of Mosquito Run at Matthews Brake National Wildlife Refuge was described in Leflore County, Mississippi, using a littoral zone point survey. Mosquito Run is a cypress-tupelo gum backswamp whose hydrology is dominated by fluvial processes within the Mississippi Alluvial Plain. This survey described a species rich aquatic plant community with substantial infestation of invasive species. The dominant submersed macrophyte, however, was Utricularia macrorhiza, a native aquatic plant which was previously presumed absent in Mississippi. This observation acts as the first record of this species in Leflore County, Mississippi and the greater Mississippi Delta. These findings assert the importance of continue floristic surveys, particularly of aquatic ecosystems, in Mississippi and the greater southeastern United States.

Houstonia montana Small (Rubiaceae) is a federally-listed herbaceous perennial known only from 16 populations across the rock outcrops and grassy balds of North Carolina, Tennessee, and Virginia. Species recovery objectives include augmentation and/or (re)introduction into suitable habitat and the establishment of a long-term conservation collection. However, before any action involving germplasm storage or plant propagation can be pursued, the seed biology of the species must be more fully understood. This study aimed to assess the effect of pre-stratification dry storage time on germination success. Seeds were collected from two populations of H. montana in October 2023 and subsequently stored at dry, ambient conditions for three durations of time: two weeks, three months, and six months post collection. After dry storage, seeds were cold-stratified in moist filter paper at 3°C for 60 days and then transferred to moist filter paper in petri dishes for germination under controlled conditions in a growth chamber. Germination reached 88–100% across the dry storage treatments and populations, indicating high seed viability for seeds stored up to six months before cold stratification. Time-to-event analysis identified a significantly faster germination rate for seeds stored for two weeks post-harvest compared to seeds stored for three or six months but there were no significant differences in germination rate in the latter two treatments. Collectively, the results provide a basis for the timing and planning of projects requiring seed germination of Houstonia montana and point towards a two-week dry storage time before cold stratification for quick germination with high seedling yield.