Control of germination and early development in parasitic angiosperms

By definition, parasitic plants are a highly specialized group of organisms that derive all, or part, of their nutrition from other plants. There are both foliar and root parasite species. Combined, these plants represent at least eight different families and include mistletoe (Arceuthobium and related genera), dodder (Cuscuta), gerardia (Agalinis), sandalwoods (Buckleya and Thesium), broomrape (Orobanche) and witchweed (Striga) species. Most parasitic plants are hemiparasites that like Agalinis purpurea, photosynthesize, flower and mature to seed-set without a host. In contrast, species such as beechdrops (Epifagus virginiana) and squawroot (Conopholis americana) are holoparasites. These plants lack chlorophyll and are host-dependent for completion of seed-set. Yet other holoparasites, such as Striga asiatica, are photosynthetic, but remain dependent upon their host for other reasons.