1. Lavatera trimestris L.

Map 2055

Plants annual. Stems 30–120 cm tall, erect or ascending, branched or unbranched, pubescent with downward-pointing simple or fasciculate hairs, these usually with somewhat pustular bases. Leaves long-petiolate. Stipules 3–5 mm long, narrowly elliptic-lanceolate, shed early, hairy. Leaf blades 2–6 cm long, ovate to nearly circular in outline, at least the upper ones 3-angled or shallowly 3-lobed, the base broadly rounded or truncate to shallowly cordate, narrowed to a pointed tip, the margins finely scalloped or toothed, the surfaces glabrous or pubescent with appressed, simple or less commonly fasciculate hairs, usually with stellate hairs at the base. Flowers solitary in the leaf axils, the bractlets subtending the calyx fused into a cup with 3(6) broadly triangular lobes, shorter than the calyx, becoming enlarged and flattened horizontally at fruiting. Calyces 9–14 mm long at flowering, expanding to 25 mm long at fruiting, lobed 2/3–3/4 of their length, initially cup-shaped, but becoming enlarged and flattened horizontally at fruiting, the lobes lanceolate to broadly triangular, the outer surface pubescent with stellate hairs and simple or fasciculate hairs along the margins. Petals 2.5–4.5 cm long, reddish pink or less commonly pinkish purple, red, or white, the broadly rounded to truncate or less commonly shallowly notched tips with a more or less entire margin. Stamens numerous, the staminal column circular in cross-section, without a low crown of teeth at the tip, glabrous or hairy toward the base, the anthers white, red, or purple. Pistils with 5–12 locules, the carpels arranged in a flattened ring about an expanded central column, this becoming enlarged and expanded at fruiting into a broad concave disc covering and hiding the fruits. Styles fused most of their length, each branch with a single linear stigmatic area along the inner side toward the tip. Fruits schizocarps breaking into 5–12 mericarps. Mericarps 3.0–3.5 mm long, indehiscent or tardily dehiscent longitudinally, more or less wedge-shaped, oblong to kidney-shaped in profile, beakless, the dorsal and rounded lateral surfaces thin and papery, with a fine but noticeable reticulate pattern of thickenings, 1-seeded. Seeds 2.5–3.0 mm long, kidney-shaped to nearly circular in outline, black or less commonly dark brown. 2n=14. August–September.

Introduced, known from a single specimen from Iron County (native of Europe, Asia; escaped sporadically in the southern U.S.). Open disturbed areas.

The single Missouri specimen of this species, which was originally determined as the superficially similar Malva sylvestris, was collected from a picnic ground in 1993. The species is sometimes cultivated as an annual bedding plant and is also a component of some wildflower seed mixes, but rarely becomes established outside cultivation in the United States.