7. Linum virginianum L. (Virginia yellow flax)

Pl. 446 j– l; Map 2024

Plants perennial. Stems 25–80 cm long, solitary or more commonly several, glabrous, with fine longitudinal lines but not ridged (circular in cross-section), occasionally with small wings of tissue descending from an extension of some leaf midveins. Leaves opposite toward the stem base, alternate toward the tip. Stipules absent. Leaf blades 2–3 cm long, 4.5–7.0 mm wide, elliptic or occasionally elliptic-obovate, narrowed to a sharply pointed tip, the margins entire. Sepals 1.5–3.5 mm long, lanceolate to narrowly ovate, those of the outer whorl with entire margins, those of the inner whorl with only a few minute sometimes glandular teeth toward the tip. Petals 3.5–5.5 mm long, yellow. Styles distinct, 1.0–1.6 mm long. Fruits readily shattering, falling from the plant soon after maturity, 1.3–1.8 mm long, 2.0–2.5 mm in diameter, depressed-globose, breaking into 10 mericarps, each 1-seeded, the mericarps flattened across the dorsal surface, the septa sparsely hairy along the ventral margins. Seeds 1.0–1.5 mm long, reddish brown. 2n=36. May–September.

Uncommon to scattered in the Ozark and Ozark Border Divisions (eastern U.S. west to Iowa and Alabama; Canada). Glades, upland prairies, loess hill prairies, tops of bluffs, savannas, banks of streams and rivers, and rarely fens; also roadsides.

Steyermark (1963) overlooked the presence of L. virginianum in Missouri and misdetermined specimens as either L. medium or L. striatum. At about the same time, C. M. Rogers (1963) confirmed its presence in the state. The species is conspicuously uncommon in Illinois and the Missouri populations are somewhat disjunct from the eastern portion of the distributional range of the species.