Plants annuals or short-lived periennial herbs or subshrubs 0.15-0.6 m tall, with simple hairs only; stems with mostly short, retrorse of appressed hairs. Leaves petiolate; blades narrowly ovate or elliptic, up to 11-55 mm long, 4-25 mm wide, bases cuneate, margings entire to narrowly serrulate, tips acute. Inflorescences with more or less well-spaced flower clusters; bracts peristent or deciduous. Fruiting calyces 4-5 mm long, open, throats hairy, uppeer lobes suborbicular, about 3mm long and wide, bases rounded, lateral lobes deltoid, cuspidate, lower lobes not connate, lanceolae, acuminate; corollas 4-6 mm long, white or pale mauve; anterior stamens 1-3 mm longer than the lower corollas lips. Nutlets about 1.6 mm long, 0.8 mm wide, almost smooth, black, producing mucilage when wet.
Ocimum americanum is a weedy species i, growing along roadsides, in abandoned fields, on disturbed groun, in Acacia bushalnd, and sometimes cultivated at 15-1500 m. It has been found in N1, N3, C1, and S1-S3 of the Flora of Somalia, widespread in the tropics.