20. Stellaria L. (stitchwort, chickweed)

Plants annual or perennial. Stems erect or ascending to reclining or spreading, unbranched or more commonly branched, often above the midpoint, glabrous, sparsely papillate, or with hairs in 2 longitudinal lines. Leaves opposite, fused basally into a small sheath, short-petiolate (some basal leaves) or sessile, lacking axillary clusters of leaves. Stipules absent. Leaf blades linear, lanceolate, oblong, ovate, triangular-ovate, or elliptic, not fleshy, tapered to rounded or nearly truncate at the base, angled or tapered to a sharply pointed tip. Flowers in terminal or axillary open panicles or clusters or sometimes solitary, the stalks ascending or arched to curved, at fruiting sometimes angled downward from the base, the bracts paired and resembling small leaves and green or much reduced, scalelike, and translucent to white with at most a green midrib. Epicalyx absent. Sepals (4)5, distinct or fused at the base, lanceolate or triangular to ovate-elliptic, green, the margins green or thin and white to translucent, bluntly or sharply pointed at the tip, not hooded or awned. Petals 5 (often appearing as 10) or absent, when present variously shaped, angled or tapered but not to a stalklike base, deeply lobed at the tip to 2/3–4/5 of the way to the base, white, lacking appendages. Stamens 1–10 (most commonly 5 or 10), the filaments distinct, attached along a small nectar disc. Staminodes usually absent. Pistil with 1 locule, the ovary sessile. Styles 3 (2, 4, or 5 elsewhere), distinct, each with a subterminal or terminal stigmatic area. Fruits capsules, dehiscing apically by 6 ascending to recurved valves or teeth. Seeds 10–20 or more, kidney-shaped to circular in outline, the surface smooth, tuberculate, or coarsely wrinkled, yellowish brown to brown or nearly black, lacking wings or appendages. About 190 species, nearly worldwide, most diverse in temperate regions; introduced nearly worldwide.

In addition to the species treated below, one other species should be mentioned. Stellaria pubera Michx. (great chickweed, star chickweed) is a plant of rich woodlands in many areas to the east and southeast of Missouri. Steyermark (1963) included this species with some reservations, based on a single historical collection from Franklin County. However, Yatskievych and Turner (1990) excluded it from the states flora because John Kelloggs collection in 1927 almost certainly originated from plants cultivated at what was then the Missouri Botanical Gardens recently acquired property in Gray Summit (now Shaw Nature Reserve). Stellaria pubera would key imperfectly to either S. media or S. neglecta in the key to species below. It differs from both of these species most noticeably in its showier flowers with the petals 4–8 mm long and distinctly longer than the sepals. Although no populations have been discovered in the state in spite of Steyermarks treatment of the species, perhaps it will be found somewhere in eastern Missouri in the future.