1. Gentianella quinquefolia (L.) Small ssp. occidentalis (A. Gray) J.M. Gillett (stiff gentian, ague weed)

Gentiana quinquefolia L. var. occidentalis A. Gray

Pl. 419 f; Map 1874

Plants annual or less commonly biennial herbs. Stems 20–80 cm long, often branched above, ridged or narrowly winged, square in cross-section, the ridges and wings minutely toothed. Leaves opposite, broadly ovate, 10–60 mm long, with clasping bases and minutely denticulate margins. Inflorescences terminal and axillary, clusters or small panicles, the lower ones sometimes reduced to a solitary flower. Flowers with parts in whorls of (4)5. Calyces 6–15 mm long, tubular, the elliptic-lanceolate to oblanceolate lobes slightly longer than the tube. Corollas 15–25 mm long, blue to whitish, commonly lavender blue, narrowly funnelform, the lobes erect or somewhat spreading, ovate to triangular and strongly tapered, about half as long as the tube; inconspicuous nectar glands present at base of corolla; stamens free, included; ovary elongate, short-stalked; style short or absent; stigmas 2, persistent; capsule fusiform, protected by the persistent calyx and dried corolla. 2n=36. August–November.

Widely scattered in the eastern half of the state (Minnesota, Kansas, and Arkansas east to Ohio and Virginia; Canada). Ledges of bluffs, banks of streams, and bottomland forest; often on calcareous substrates.