Flora of the Southeastern United States

Rhynchospora inundata (Oakes) Fernald. Common name: Narrow-fruit Horned Beaksedge. Phenology: Jul-Sep. Habitat: In water of limesink dolines and clay-based Carolina bays. usually found in shallow water or at the lower margins of pond-shores, typically producing large colonies. Distribution: Apparently ranging from e. MA south to s. FL and west to e. TX (the range, however, obscured by confusion with R. corniculata) (Singhurst, Mink, & Holmes 2010). See Reid (2021) for information about its occurrence in Vermilion Parish, w. Louisiana.

ID notes: With its robust size and very open inflorescences, Rhynchospora inundata is often confused with R. corniculata and R. careyana. From them it differs by the seed bristles being much longer than the seed body, versus equal to or shorter in the other two species. From R. macrostachya it differs in the very open inflorescence (vs. tight clusters) and the presence of long horizontal rhizomes (vs. none in that species).

Origin/Endemic status: Native

Taxonomy Comments: The relation of this species to R. careyana and to more northern entities of R. inundata remain incompletely understood.

Synonymy ⓘ: = C, F, FNA23, G, GW1, K4, NE, NS, NY, POWO, McMillan (2007); = Rynchospora inundata — S; < Rhynchospora inundata (Oakes) Fernald — RAB, WH3; < Rynchospora corniculata (Lam.) A.Gray) var. macrostachya (Torr. ex A.Gray) Britton — S13; Ceratoschoenus macrostachyus (Torr. ex A. Gray) A. Gray var. inundatus Oakes. Basionym: Ceratoschoenus macrostachyus (Torr. ex A. Gray) A. Gray var. inundatus Oakes 1841

Links to other floras: = Rhynchospora inundata - FNA23

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Wetland Indicator Status:

• Atlantic and Gulf Coastal Plain: OBL
• Eastern Mountains and Piedmont: OBL
• Great Plains: OBL
• Northcentral & Northeast: OBL

Heliophily ⓘ: 8