Cor salverform or broadly funnelform, the tube often shorter than the cal, the throat obstructed by the fornices; stamens and style included; fruiting pedicels short, recurved or reflexed; nutlets attached by a lanceolate to ovate area occupying the middle third only, the dorsal surface lance-ovate, bordered by a row of glochidiate prickles, and in some spp. with similar prickles on the surface; mostly taprooted perennials, or a few spp. biennial or even annual, with numerous, usually paired false racemes terminating axillary branches, these racemes naked above, leafy-bracteate at base; fls blue or white, small. 45, N. and S. Amer. and Eurasia.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.