Solanum nigrum L.
CC = *
CW = 3
MOC = 3
Family - Solanaceae
Habit - Taprooted annual forb, sometimes short-lived perennial.
Stems - Loosely ascending to erect, to 60 cm, widely branching, mostly glabrous but with some strigose hairs on the newest growth, terete or angled, minutely winged from decurrent petiole tissue.
Leaves - Alternate, petiolate. Petioles to +/-4cm long, winged by decurrent blade tissue or not. Blades typically ovate, acute, with wavy margins or a few coarse teeth (the teeth with rounded apices), to +/-10cm long, +/-7cm broad, sparse strigose above and below, deep dull green above, light green below.
Inflorescence - Loose pedunculate umbels or corymbs from the sides of the stem in the internodes. Peduncles to 3cm long, strigose, erect. Pedicels to 1cm long, strigose, spreading to erect in flower, nodding in fruit.
Flowers - Corolla white, 5-lobed, 1cm broad, glabrous. Lobes lanceolate-triangular, 4-5mm long, +/-2mm broad. Corolla tube green, -2mm long, glabrous. Stamens 5, adnate at the apex of the corolla tube, erect, exserted. Filaments green, 1-1.3mm long, with some cilia on margins. Anthers yellow, 2mm long, converging around the style. Ovary superior, green, glabrous, ovoid, 1.2mm long in flower. Style green, glabrous in the apical half, hispidulous in the basal half, 3mm long. Stigma globose-capitate. Calyx tube green, 1mm long, antrorse strigose externally, glabrous internally, 5-lobed. Lobes 2-3mm long, somewhat unequal, 1-1.3mm broad, subacute at the apex, subulate to linear-oblong. Fruit a globose berry to +/-7mm in diameter, blackish when mature, shiny or not. Seeds many.
Flowering - May - November.
Habitat - Waste ground, disturbed sites, open woods, pastures, roadsides, railroads.
Origin - Native to the U.S.
Lookalikes - S. ptychanthum, S. americanum, S. sarrachoides.
Other info - This species is probably uncommon in Missouri, thus far documented from very few counties. However, its differentiation from the far more common S. ptychanthum is subtle, based in part upon the inflorescences being short racemes rather than strict umbels. This feature is shown in the infructescence photo above, in which a short internodal axis is clearly visible. In contrast, an umbel would have all fruit stalks arising from a single node. The difference is slight enough that the species may often go unrecognized in the field. Further compounding the problem, the entire complex (S. ptychanthum, S. nigrum, and S. americanum) is somewhat cryptic and / or controversial. These three species can be very difficult to distinguish.
Photographs taken off Hwy 60, Carter County, MO., 7-19-03.