PLANTS: Glabrous, annual, biennial or perennial herbs. LEAVES: opposite, entire, membranous or fleshy, sessile or petioled, 3-5-veined. INFLORESCENCE: axillary or terminal, loose or dense cymes. FLOWERS: calyx 4-parted, the lobes linear, lanceolate, ovate or spatulate, usually papillate, often with small scales at the base of each lobe; corolla 4-parted, campanulate, white, yellow, green or purple, the tube of varying lengths, the lobes elliptic to ovate, obtuse to acute or apiculate, entire or erose, commonly spurred and papillate; stamens 4; pistil sessile, the stigmas 2, sessile. SEEDS: globose or slightly flattened, granular or reticulate. NOTES: ca. 75 spp. N., C. and S. Amer. and Asia. (Named for J. P. Halen[ius] a collaborator with Linnaeus and author of early flora of Kamchatka). Allen, C. K. 1933. Ann. Missouri Bot. Gard. 20: 119-223. REFERENCES: Mason, Charles T. 1998 Gentianaceae. J. Ariz. - Nev. Acad. Sci. 30(2): 84.
Fls 4-merous; cal-tube short, campanulate, with foliaceous lobes; cor (in ours) nearly tubular to somewhat narrowed distally, lobed to below the middle, prolonged at base (at least in some fls) into short, divergently retrorse spurs; stamens at the summit of the cor- tube, shorter than the lobes; ovary conic, gradually tapering to the short style; stigma 2-lobed; fr lanceolate, acute; herbs with opposite or basal lvs and small fls in cymose clusters terminating the stem and branches or forming a somewhat thyrsoid infl. 100, mainly New World.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.