Article from Bean's Trees and Shrubs Hardy in the British Isles
Recommended citation
'Psoralea' from the website Trees and Shrubs Online (treesandshrubsonline.
A genus of over 100 species, mostly shrubs and subshrubs, natives mainly of the tropics and subtropics of both hemispheres, but a few temperate. Of the shrubby species, the one described here is almost hardy. The type of the genus – P. pinnata L., from S. Africa – is tender, but could probably be grown outside in the mildest parts.