Otacanthus
(from ous, otos, an ear, and acanthos, a thorn; in allusion to the prickly leaves). ORD. Acanthaceae. A small genus (two species) of handsome, erect, branched, pubescent, stove herbs or sub-shrubs, natives of South America. Flowers white or bluish, showy, solitary in the axils, sub-sessile; corolla with a long tube and a bilabiate limb. Leaves entire or toothed. For culture, see Ruellia.
O. caeruleus (sky-blue). fl. bluish purple, flattish, disposed around the shoot, axillary in the few uppermost leaves. l. opposite, ovate-acuminate, strongly serrated. Brazil, 1862. (F. d. S. 1526.)