5. Malva sylvestris L. (high mallow)

M. sylvestris var. mauritiana (L.) Boiss.

Pl. 453 e, f; Map 2060

Plants biennial (perennial in warmer climates). Stems 40–150 cm long, erect or ascending, glabrous or sparsely pubescent with stellate hairs. Stipules 3–8 mm long, linear to ovate-triangular. Leaf blades 2–8 cm long, flat or somewhat crisped or curled toward the margins, circular to broadly kidney-shaped in outline, unlobed to 3–7-angled or broadly and shallowly lobed (much less than 1/2 way to the base), the margins finely scalloped or toothed, the surfaces glabrous or sparsely pubescent with mostly simple or fasciculate hairs, also usually with stellate hairs at the base. Flowers in axillary clusters, long-stalked, the bractlets subtending the calyx oblong-ovate to narrowly obovate, glabrous or sparsely hairy, except along the margins. Calyces 5–6 mm long at flowering, expanding to 9 mm long at fruiting, initially cup-shaped, but becoming slightly enlarged and somewhat flattened horizontally at fruiting, with a distinct network of veins toward the base, the outer surface pubescent with mostly stellate hairs, the marginal hairs stellate and fasciculate, all less than 0.5 mm long. Petals 1.5–2.5 cm long, reddish purple. Fruits 2.0–2.5 mm long, flat on the dorsal surface, glabrous or somewhat hairy, moderately to strongly wrinkled or with a reticulate pattern of thickenings, angled at the junction between the dorsal and lateral surfaces, the sides thin and papery, with a radiating network of thickened veins. Seeds 1.5–2.2 mm long. 2n=42. May–July.

Introduced, widely scattered in Missouri (native of Europe, Asia; escaped sporadically in North America). Roadsides, railroads, and open disturbed areas.

Malva sylvestris is cultivated as an ornamental in gardens and occasionally escapes from cultivation.