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.