Coarse, erect, often freely branched winter-annual or biennial, mostly 0.5-2 m; lvs thin, lanceolate to ovate-oblong, 7-15 cm including the margined petiole, acuminate, serrate; spike(s) 1-4+ dm, the lower bracts lf-like, the upper reduced; fls blue, solitary or in small clusters, the rotate cor 2.5 cm wide; sep linear, spreading, 5-10 mm; pollen pantoporate (unique among our spp.); style down-curved, with upcurved tip; fr 7-12 mm, opening by round pores near the top; 2n=58. Moist borders and open woods; Ont. to Minn., s. to Fla. and Okla. July-Sept. (Campanulastrum a.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.