The flowers of Nemastylis geminiflora open midmorning and fade before sundown.

There seems to be no merit in recognizing Nemastylis texana (E. Whitehouse 1936) for plants from southern Texas, said to have steel-blue flowers, more frequently found in oak woodlands than in prairies. Reports in the literature of N. geminiflora from Tennessee appear to be incorrect, possibly based on an early record from “E. Tennessee” (Dr. Eight s.n., NY).