1. Atocion armeria (L.) Raf. (sweet William catchfly)

Silene armeria L.

Map 1449, Pl. 345 f

Plants annual or biennial. Stems (10–)20–40 cm long, erect or ascending, usually unbranched below the inflorescence, glabrous or rarely sparsely to moderately stipitate-glandular toward the tip. Leaves opposite, fused basally into a sheath, sessile and sometimes clasping the stem, lacking axillary clusters of leaves. Stipules absent. Leaf blades 1–6 cm long, oblong-lanceolate to elliptic or ovate, not fleshy, tapered (lower leaves) or truncate to cordate at the base, angled to a bluntly or more commonly sharply pointed tip. Flowers in terminal clusters, these grouped into small panicles, the stalks 0.1–0.5 cm long, erect or spreading, the bracts scalelike or leaflike. Epicalyx absent. Sepals 5, 13–17 mm long, fused into a narrow tube, the tube 10-nerved, purplish, and slightly thinner between the lobes, the lobes ovate to triangular, shorter than the tube, angled to a bluntly pointed tip, not appearing hooded or awned, the margins thin and white or purplish-tinged. Petals 5, 10–15 mm long, oblanceolate to spatulate, tapered to a stalklike base, the blade 0.5–0.7 cm long, entire or sometimes slightly notched at the tip, pink or purple, with two small, scalelike appendages on the upper surface at the base of the expanded portion. Stamens 10, the filaments distinct. Staminodes absent. Pistil with 3 locules, the ovary with a stalk 6–7 mm long. Styles 3, each with a stigmatic area along the inner surface. Fruits capsules, 7–10 mm long, dehiscing apically by 6 ascending to somewhat recurved teeth. Seeds 20–30(–45), 0.5–0.7 mm wide, kidney-shaped, the surface with minute papillae, dark brown, lacking wings or appendages. 2n=24. May–October.

Introduced, uncommon, known thus far only from St. Louis County and City (native to Europe and Asia; probably introduced in the eastern U.S. west to Minnesota, Missouri, and Kentucky, and in the western U.S. from Washington to California and Utah). Railroads and disturbed areas.