Description: Annual or perennial herbs, spreading or prostrate.
Leaves opposite. Racemes terminal, open. Calyx cup-shaped, unequally 5-lobed, split on the lower side to the base. Corolla tubular, 2 lipped, unequally 5-lobed.
Fertile stamens 4. Capsule not spinose, horns as long or longer than the body.
Distribution and occurrence: World: 9 species, tropical & subtropical America. Australia: 2 species (naturalized), Qld, N.S.W., Vic., S.A., W.A.
The record of P. fragrans (Lindley) Decne. for this State has not been substantiated.
Text by A. K. Brooks