Studies in the vascular flora of the southeastern United States. VIII

Abstract

As part of ongoing efforts to understand, document, and conserve the flora of the southeastern United States, we make new combinations to accord with our generic taxonomy, name a new hybrid, re-recognize a species relegated to synonymy in recent decades, lectotypify and generally clarify nomenclatural issues in several genera, clarify taxonomy and distributions of species, and report important new and current distribution records. In Doellingeria (Asteraceae), we clarify the taxonomy and distribution of D. sericocarpoides and D. umbellata in the region. In Trilisa (Asteraceae), we summarize and clarify the taxonomy, name a new hybrid, and present a new key to the taxa in the genus. Species delimitation in Stillingia (Euphorbiaceae) has been controversial and unsettled in the region, and we examine the confused taxonomy and nomenclature of the genus in the southeastern United States, re-recognizing a species used by J.K. Small, but with an expanded circumscription and a clarification of various nomenclatural issues. We examine typification of Desmodium dillenii (Fabaceae) and its application to our modern understanding of the circumscription of taxa, recommending it be considered a junior synonym of Desmodium glabellum. In Juncus, we assign a lectotype for Juncus anthelatus, fixing its application. In Primulaceae, we discuss the delineation of genera in Lysimachieae, and take a middle path regarding lumping/splitting, supporting the recognition of traditional and monophyletic segregates Trientalis, Steironema, Anagallis, and Centunculus, while treating Lysimachia in a moderately broad sense, including Glaux and multiple subclades; in order to implement this taxonomy in the southeastern United states, we make a single new combination in Steironema. We also discuss generic circumscription in Selaginellaceae, and argue for the recognition at genus rank of six major clades, monophyletic, ancient, and morphologically recognizable; in order to apply this taxonomy in the southeastern United States, we make five new combinations in Bryodesma, Gymnogynum, and Stachygynandrum. Finally, we report important new records of locally, regionally, or globally rare species in North Carolina: Helanthium tenellum, Chenopodium berlandieri var. macrocalycium, Carex barrattii, Carex vestita, Eleocharis compressa var. compressa, Rhynchospora compressa, Rhynchospora sulcata, and Croton michauxii.