Ocimum americanum
Semi-woody herb up to 50 cm tall, aromatic. Solitary stem, very branched, hairy. Leaves up to 2.5 cm long, ovate to elliptic, sparse pubescent, glandular spiny base, attenuate base, with serrated edges distally. Flowers white or pinkish purple, shiny, with persistent underlying bracts, up to 5 mm, slightly puberulous; corolla 4 to 6 mm, tube 4 to 5 mm. Fruit with 4 nutlets 1.5 to 2 mm long, dark brown.
Distribution: native to the tropics of the Old World, frequently found in tropical America.
Calotropis procera
Shrub, 2 to 5 m high, evergreen. Straight, sometimes tortuous, whitish stems; Corky bark with deep fissures in old branches. Glaucous leaves, sessile, oblong-obovate to almost orbicular, 10 to 30 cm, usually cuspidate, armored at the base, with velvety white tomentum when young, glabrous with age. Branched inflorescences, in extra-axillary umbelliform clusters, pedunculate, with many flowers, petals white with purple tips. Fruits of 3 to 10 cm, swollen follicles, large, obliquely ovoid.
Distribution: Pantropical.