Perennial herb 30 cm - 0.7 m tall Stem: clustered. Leaves: numerous, 1 - 3 cm long, linear, single-veined or somewhat three-veined at base. Flowers: scattered in leafy terminal inflorescences, with five blue petals 1 - 2.3 cm long. The five sepals are 5 - 7 mm long, egg-shaped with a blunt or short abrupt tip (mucronate), and toothless. Fruit: a capsule, 5 - 9 mm across, egg-shaped to nearly spherical, slightly beaked, soon splitting into ten segments with pointed tips.
Similar species: Linum perrenne and Linum usitatissimum both have blue petals and wider fruit (5 - 10 mm) than the other Linum species in our region. Linum usitatissumum is distinguished by its annual life cycle, single stem, sepals with long pointed tips, toothed inner sepals with fringed hairs along the margin, and leaves with three veins.
Habitat and ecology: Introduced from Europe, this species is found in sandy soil along roadsides.
Occurence in the Chicago region: non-native
Etymology: Linum is the Latin name for flax. Perenne means perennial.
Perennial, 3-7 dm, the stems mostly clustered; lvs erect, very numerous, linear, 1-3 cm, 1-nerved, or obscurely 3-nerved at base; fls heterostylic; sep ovate, 5-7 mm, obtuse and minutely mucronate, entire; pet blue, 12-23 mm; staminodes subulate or tooth-like, 1 mm; stigmas ellipsoid-capitate; fr 5-9 mm, ovoid-globose, scarcely beaked, the 10 segments acute or shortly acuminate; false septa incomplete, long-ciliate; 2n=18. Native of Europe, occasionally intr. in disturbed habitats in our range, as in Wis. and Mich., where it has been mistaken for the closely allied homostylic cordilleran sp. L. lewisii Pursh. May-July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.