Branching annual, 1.5-6 dm, glabrous, or somewhat strigose or incurved-puberulent especially above; lvs petiolate; ovate to deltoid, irregularly blunt-toothed or subentire, 2-8 נ1-5.5 cm; peduncles numerous, ascending, to 3 cm, the pedicels closely clustered (forming an umbelliform infl), mostly deflexed at least in fr; mature cal 2-3 mm, the lobes often unequal, sometimes reflexed; cor white or faintly bluish, 5-10 mm wide; frs globose, black, 8 mm, poisonous at least when young, many-seeded and often with 1-10 subglobose concretions to half as long as the seeds; polyploid series based on x=12. A cosmopolitan weed of disturbed habitats, highly diversified, but not yet satisfactorily resolved into discrete taxa, in spite of many attempts. The native N. Amer. plants, as here described, are all diploid, so far as known; the oldest name for these at the specific level may be S. ptychanthum Dunal (S. americanum Mill., probably misapplied). At the varietal level the name would be S. nigrum var. virginicum L. Typical European S. nigrum is only casual with us, mainly about our large Atlantic ports. It is hexaploid and more pubescent (the hairs short, ±spreading and somewhat viscid), with a more nearly racemiform (but still compact) infl.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.