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How close relatives maintain species boundaries in sympatry remains a critical question in biodiversity research. Here we introduce Lobelia sect. Lobelia (Campanulaceae) as a useful clade for investigating such questions. Polyphyly within this clade was strongly suspected because many of the 26 species are cross-compatible and show remarkable overlap in distribution, morphology, ecology, and life history. Indeed, the species Lobelia × rogersii has a purported hybrid origin from Lobelia puberula and Lobelia brevifolia, and the well-known cultivar Lobelia × speciosa results from mating between Lobelia siphilitica and Lobelia cardinalis. We carried out a comprehensive evolutionary investigation of Lobelia sect. Lobelia, including phylogenetic inference, divergence time estimates, and population structure analyses using 729 accessions from 193 natural population sites representing 1–13 individuals per population per species. In contrast to expectations, nearly all species were recovered as reciprocally monophyletic with strong topological support and low levels of interspecific gene flow. An exception to this general pattern is observed in the Florida panhandle, where Lobelia glandulosa and Lobelia apalachicolensis co-occur and appear to be actively hybridizing. We conclude that North American Lobelia species are genetically cohesive, despite significant geographic overlap, frequent co-occurrence, morphological similarity, and broad interfertility in artificial crosses. 

Since its original publication in 1789, Vaccinium virgatum has been treated by most authors as an accepted species in V. sect. Cyanococcus. In the latest comprehensive taxonomic treatment of the section, however, it is treated as a synonym of the broadly circumscribed species V. corymbosum. Here we use a combination of morphology, ploidy assessment with flow cytometry, and previously published phylogenomic analysis based on high-throughput DNA sequencing to support the taxonomic status of V. virgatum as a species to be recognized. As circumscribed here, V. virgatum occurs in the southeastern U.S. Coastal Plain from Arkansas, Texas, and southeastern Oklahoma to northeastern Florida and southeastern North Carolina. An updated taxonomic treatment of the species, including an expanded description, distribution map by county, and a representative list of specimens examined by county is included. We provide a means of distinguishing V. virgatum from V. ashei, a similar species recently also segregated from V. corymbosum, and from presumed rabbiteye blueberry escapes from cultivation, which can occur both within and outside the native range of V. virgatum. We designate a neotype for V. virgatum and lectotypes for V. virgatum vars. angustifolium, parvifolium, and speciosum. 

Since its original publication in 1789, Vaccinium virgatum has been treated by most authors as an accepted species in V. sect. Cyanococcus. In the latest comprehensive taxonomic treatment of the section, however, it is treated as a synonym of the broadly circumscribed species V. corymbosum. Here we use a combination of morphology, ploidy assessment with flow cytometry, and previously published phylogenomic analysis based on high-throughput DNA sequencing to support the taxonomic status of V. virgatum as a species to be recognized. As circumscribed here, V. virgatum occurs in the southeastern U.S. Coastal Plain from Arkansas, Texas, and southeastern Oklahoma to northeastern Florida and southeastern Carolina. An updated taxonomic treatment of the species, including an expanded description, distribution map by county, and a representative list of specimens examined by county is included. We provide a means of distinguishing V. virgatum from V. ashei, a similar species recently also segregated from V. corymbosum, and from presumed rabbiteye blueberry escapes from cultivation, which can occur both within and outside the native range of V. virgatum. We designate a neotype for V. virgatum and lectotypes for V. virgatum vars. angustifolium, parvifolium, and speciosum. 

As part of ongoing work on the Flora of the Southeastern United States (Weakley & Southeastern Flora Team 2023) and related projects, as well as for general floristic, conservation, and scientific work in eastern North America, it is essential to document taxonomic and nomenclatural changes and significant distribution records. Here, we propose six new species of graminoids (two Rhynchospora, three Dichanthelium, and one Anatherum)—five from fire-maintained pine savannas and embedded wetlands of the southeastern Coastal Plain and one from the floristically and ecologically related fire-maintained pine savannas of North Andros Island in The Bahamas. We provide rationale and documentation for the “taxonomic resurrection” of Vaccinium ashei, an economically important member of Vaccinium sect. Cyanococcus, based on morphology, estimation of ploidy level with flow cytometry, and phylogenomic analysis based on high-throughput DNA sequencing. We make four new combinations in Convolvulus to accommodate the inclusion of Calystegia in Convolvulus to resolve paraphyly. We also make six new combinations necessary to recognize sect. Leptopogon of Andropogon at generic rank, as Anatherum, based on the phylogenetic work of other researchers and the previously incomplete transfer of recognized species to Anatherum, providing the needed names to recognize this group of species in genus Anatherum in North American floristic treatments. We document the surprising discovery of Carex lutea, previously believed to be endemic to two counties in eastern North Carolina, in two counties in the panhandle of Florida, and a county in eastern South Carolina—discoveries aided by iNaturalist and Facebook. We document new states as being within the distribution ranges of additional species: Quercus similis (Florida), Juncus brachycephalus (Arkansas and Missouri), Rhexia mariana var. mariana (Ohio), Asarum acuminatum and Elionurus tripsacoides (Alabama), and Mecardonia procumbens (Georgia). Other important distributional records, many representing rediscoveries of conservationally significant, extant populations of plants previously considered of only historical occurrence in a state, are also reported: Alabama (Arnica acaulis, Asclepias connivens, Berberis canadensis, Bulbostylis warei, Ctenodon viscidulus, Parnassia grandifolia, and Pinguicula pumila) and Georgia and Florida (Lobelia boykinii).