Flora of North America species comparison

Varieties 3 (3 in the flora).

Linum lewisii grows in many habitats in western North America from northern Mexico to Alaska east to the Great Plains in the United States and to the west side of Hudson and James bays in Canada; it appears to be less common in the Great Basin. A component of wildflower seed mixes, the species may be expanding its range. Some authors have considered it conspecific with L. perenne, and many collections in herbaria are identified as L. perenne without an indication of variety; they are most likely L. lewisii var. lewisii (D. J. Ockendon 1971; C. M. Rogers 1984). Because of the prevalence of L. bienne, L. perenne, and L. usitatissimum in bird seed and wildflower mixes, it may be that these three non-natives are becoming more common than in the past. Capitate stigmas distinguish L. lewisii from L. bienne and L. usitatissimum, which have linear or clavate stigmas. Distinguishing L. lewisii from L. perenne is more difficult: the size of flower parts in the homostyled L. lewisii varies along elevational and latitudinal gradients, with smaller flowers and flower parts in higher elevations and higher latitudes; except in var. lepagei, the styles are always longer than the stamens. In the heterostyled L. perenne, populations usually include plants in which flowers have stamens much longer than the very short styles (short-styled form) and plants in which flowers have stamens much shorter than the very long styles, up to twice as long as the stamens (long-styled form).

C. A. Kearns and D. W. Inouye (1994) reported that Linum lewisii is facultatively autogamous but tends not to set seed in the absence of pollinators; small bees and flies are the most common pollinators. A. Cronquist et al. (1997b) reported unusual populations of L. lewisii on sandy soil in Nye County, Nevada, in the 40-Mile-Canyon drainage, that had persistent, ascending, pale blue petals with darker veins.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Linum usitatissimum has been cultivated since antiquity, and it is this cultivated form that has naturalized in the wild. Flax fibers twisted to make rope or dyed for fabric dated 32,000–26,000 years before present were found in a cave in Dzudzuana, Georgia (E. Kvavadze et al. 2009). Stem fibers of L. usitatissimum are used to make linen; the seeds are pressed to produce linseed oil; the rest of the seeds are compacted into cakes and used as fodder. Linum usitatissimum is the only species in the flora area except L. bienne that has linear stigmas and minutely ciliate inner sepals. It can be distinguished from L. bienne by its larger, apically rounded capsules.

(Discussion copyrighted by Flora of North America; reprinted with permission.)