Branchlets glabrous. Leaves: Inflorescence a lax axillary cyme, 4-11 cm long, minutely puberulent on upper parts; Sepals ovate, 2.1-4 by 1.2-2.9 mm, 1.2-1.9 times as long as wide, apex obtuse to acuminate, sparsely shortly puberulent outside. Stamens inserted at 2.7 mm from corolla base which is 0.5 of tube length; Ovary 1-1.7 mm long; Fruit fusiform, with long irregular spine-like outgrowths of the fruit wall; Seeds:
This species is closest to P. flavescens from which it differs in the rounder head of the corolla bud and the spines on the fruit. It has been reported as being used as a treatment for diarrhoea.