Linum usitatissimum L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Annual; stems 1–several, erect, to 1 m; lvs lance-linear, 3-nerved, 1.5–3.5 cm; sep 7–9 at maturity, the inner minutely ciliate on the scarious margin; pet blue, 10–15 mm; staminodes minute, tooth-like; stigmas linear-clavate; fr 6–10 mm, subglobose and abruptly short-beaked, tending to be only tardily and incompletely dehiscent, the mericarps acuminate; false septa very incomplete, long-ciliate; 2n=30. European cultigen, often escaped or adventive in fields and roadsides in U.S. and s. Can. Summer. (L. humile)