L. usitatissimum: annual; stems 1-2 feet high, erect, glabrous, usually branched only at the top; leaves alternate, erect, narrow-lanceolate, pointed, entire; flowers rich blue, in a loose terminal corymb; sepals pointed; petals obovate; capsule globular or slightly depressed. - Linseed. - A weed of cultivation. Fl. July.
L. perenne: stem 1-2 feet long, erect or decumbent; very variable, sometimes resembling the last, but the stems usually more slender, the leaves smaller and narrower, and the sepals obtuse. - Dry limestone pastures. Fl. June, July.
L. angustifolium: stem 1-2 feet high, branching irregularly, decumbent; leaves narrow, linear-lanceolate; flowers smaller than the preceding, pale blue, the sepals pointed. - Limestone pastures and wastes. Fl. July.
** Leaves opposite; flowers white.
L. eatharticum: annual; stems 3-8 inches high, slender, erect, or slightly decumbent, glabrous; leaves small, opposite, obovate or oblong; flowers very small, pure white, on long slender pedicels. - Meadows and pastures. Fl. June to August.
(Go) Radiola. Allseed.
R. Millegrana: annual; minute, erect, with numerous repeatedly-forked branches, forming dense corymbose tufts, 1-2 inches high; leaves small, opposite; flowers minute, globular, white; calyx-teeth 8-12; petals about the length of the calyx. - Sandy heaths and waste places. Fl. July, August.