They are woody hemi-parasitic shrubs with branches long, which grow on other trees. The foliage is dichotomously branching, with opposite pairs of leaves; these are fairly large, long, green and photosynthetic in some species (e.g. "P. leucarpum"), but minimal in some others (e.g. "P. californicum"). Although they are able to photosynthesize the plant relies on its host for some nutrients. The plant draws its mineral and water needs, and some of its energy needs, from the host tree using a haustorium which grows into the stems of the host.