2. Calopogon tuberosus (L.) Britton, Sterns & Poggenb. (grass pink)

Pl. 111 e–g; Map 456

C. pulchellus (Salisb.) R. Br.

Corms unbranched. Flowering stems 20–60 cm long, noticeably longer than the leaf, with 3–10 flowers, these usually with each opening as the previous one nears the end of flowering. Perianth usually bright pink, sometimes magenta. Patch of club‑shaped hairs nearest the tip of the lip white, yellow, and/or orange, the more basal patches usually yellow. 2n=26. June–July.

Scattered in the Ozark and Ozark Border Divisions (eastern U.S. and adjacent Canada west to Oklahoma, Cuba). Fens.

Summers (1987) first noted that plants from mesic upland prairies tend to be shorter, flower from early May to June, and have paler pink flowers, whereas plants inhabiting wet, calcareous soils of fens tend to be taller, flower from mid–June to early July, and have brighter pink to magenta flowers. Other differences discussed by Goldman (1995) include unbranched vs. 2‑branched corms, the more acuminate buds of C. oklahomensis, and the lowermost sepal tending to be strongly curled backward in that species, rather than straight to somewhat arching in most flowers of C. tuberosus. Goldman (1995) also discussed several other characters to separate the two taxa that are more difficult to observe.