Cal-tube obconic, very thin-walled, loosely enclosing the cor; cal- lobes green, loosely spreading, lance-triangular, the 2 lateral exceeding the 2 lower, the median upper one much reduced or even wanting; cor strongly 2-lipped, the tube much dilated distally, the large upper lip subgaleately rounded, entire, the lower longer, 3-lobed; stamens 4, ascending under the upper lip, the lower pair slightly the longer; filaments hairy, incurved at the summit, bringing the anthers into contact; nutlets smooth, biconvex; perennial with solitary fls in the axils of bracteal lvs, forming a terminal spike. Monospecific.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
