A genus of about half a dozen species of deciduous or partially evergreen, soft-wooded shrubs with trifoliolate leaves and entire, stalkless leaflets. Flowers always yellow, borne in erect terminal racemes. Provided they have a suitable climate – and they are not completely hardy – they are easily grown if put in a sunny spot and given a reasonably good loamy soil.
The genus is revised by B. L. Turner in Brittonia, Vol. 32, pp. 281–5 (1980). He recognises only two species – P. nepalensis and P. tomentosus.