3. Malva parviflora L. (small-flowered mallow)

Pl. 454 g–i; Map 2058

Plants annual. Stems 40–100 cm long, erect or ascending, less commonly spreading, glabrous or sparsely to moderately pubescent with mostly stellate hairs. Stipules 4–5 mm long, linear to narrowly triangular. Leaf blades 2–7 cm long, flat or slightly crisped along the margins, circular to broadly kidney-shaped in outline, unlobed, or broadly and shallowly 5- or 7-lobed (much less than 1/2 way to the base), the margins finely scalloped or toothed, the surfaces glabrous or sparsely to moderately pubescent with simple and/or stellate hairs, especially at the base and along the veins. Flowers in axillary clusters, short-stalked at flowering, the stalks elongating somewhat as the fruits mature, the bractlets subtending the calyx linear to narrowly lanceolate, glabrous or with mostly simple hairs along the margins. Calyces 3.0–4.5 mm long at flowering, expanding to 8 mm long at fruiting, initially cup-shaped, but becoming papery, enlarged, and flattened horizontally at fruiting, with a distinct network of veins, the outer surface pubescent with mostly stellate hairs, the marginal hairs all less than 0.5 mm long. Petals 0.3–0.6 cm long, mostly slightly longer than the calyx at flowering, white, light pink, or pale lavender. Fruits 2.0–2.5 mm long, the dorsal surface flat, glabrous or finely stellate-hairy, strongly transversely wrinkled, and with a reticulate pattern of thickenings, the junction between the dorsal and lateral surfaces with a narrow toothed or undulate wing (the ring of fruits thus appearing finely ribbed between the carpels at maturity), the sides thin and papery, with a radiating network of thickened veins. Seeds 1.5–2.0 mm long. 2n=42. May–October.

Introduced, known thus far only from a historical collection from Jackson County (native of Europe, Asia, Africa, widely naturalized in the central and western U.S. south to South America, sporadic in the eastern U.S.). Roadsides and moist open disturbed areas.

The Jackson County specimen is somewhat atypical in having the calyx less enlarged at fruiting than is typical of the species farther west in its naturalized North American range.