4. Stellaria neglecta Weihe (greater chickweed)

S. media (L.) Vill. ssp. neglecta (Weihe) Murb.

Map 1499

Plants annual, green or dark green or rarely yellowish green. Stems 35–60(–80) cm long, erect or ascending to less commonly sprawling or spreading, branched, with a longitudinal line of short, stalked glands. Leaves petiolate (basal and lower stem leaves) or sessile (median and upper stem leaves). Leaf blades 0.8–5.0 cm long, broadly ovate to elliptic, rounded to nearly truncate at the base, angled or slightly tapered to a sharply pointed tip, the margins glabrous or inconspicuously hairy. Flowers not cleistogamous, in terminal clusters or sometimes solitary, the stalks 1.0–4.5 cm long, ascending at flowering, often angled downward from the base at fruiting, the bracts herbaceous and resembling small leaves. Sepals 5, 5–6 mm long, oblong-lanceolate, lacking a reddish band at the base, mostly sharply pointed at the tip, the margins thin and white, sparsely and finely hairy. Petals 5 or occasionally absent, 3–5 mm long, shorter than to about as long as the sepals. Stamens (5–)8–10. Fruits 5–6 mm long, the valves ascending with usually recurved tips at dehiscence. Seeds 1.1–1.7 mm wide, the surface tuberculate, the tubercles along the marginal portion taller than broad, conical, sharply pointed at the tip, brown to dark brown (sometimes yellowish brown before full maturity). 2n=22. April–June.

Introduced, uncommon, known thus far only from Scott and Ste. Genevieve Counties (native of Europe; introduced sporadically in the southeastern U.S. west to Oklahoma and Louisiana, also in California). Banks of streams and bases of bluffs; also lawns and disturbed areas.

First collected in Missouri from Ste. Genevieve County by George Yatskievych in 1993, S. neglecta rarely has been reported in North America. Morton (2005b) suggested that the increase in North American populations has occurred since about 1990. The present treatment follows that of Morton in including plants with the petals shorter than the sepals in this species, although most European treatments (for example, Nilsson, 2001) restrict the name S. neglecta to plants in which the petals are equal to or often longer than the sepals. North American plants do produce seeds with conical tubercles that are consistent with descriptions and illustrations from the European literature (for example, Berggren, 1981).