Juncus biflorus Elliott. Subgenus: Juncus. Section: Graminifolii. Phen: Jun-Oct. Hab: Pine savannas, pine flatwoods, mesic areas in sandhill-pocosin ecotones, roadsides, low fields in the Piedmont, wet meadows, interdune swales, freshwater and oligohaline tidal marshes, ditches. Dist: MA to MO, south to FL, TX, Mexico and Central America, and disjunct in South America.
ID notes:Among the members of section Graminifolii, which is recognizable by the flat leaves lacking setpa and rounded capsules in heads (glomerules), J. biflorus has the widest leaves, and largest and loosest inflorescence, but this can be very variable within populations. The rhizomes have numerous rhizome scales that are congested along the rhizome overlap.
Origin/Endemic status: Native
Taxonomy Comments: See Knapp & Naczi (2008) for clarification of the Juncus marginatus complex.
Synonymy: = Ar, F, Il, K1, K2, Mi, Mo1, NE, NY, RAB, Tn, Va, W, WV, Knapp & Naczi (2008); = Juncus aristulatus Michx. var. biflorus (Elliott) Small – S; < Juncus biflorus Elliott – C, G, Pa; < Juncus marginatus Rostk. – FNA22, GW1, K3, K4, Tx, WH3, Kirschner (2002b), Kirschner (2002c)