clustered broomrape

Aphyllon fasciculatum, the clustered broomrape, is an obligate root parasite in the family Orobanchaceae native to western North America, ranging from British Columbia south through the western United States to Baja California, particularly in arid and semi-arid grasslands, sagebrush steppe, and chaparral. Like all broomrapes, it lacks chlorophyll and derives all water and nutrients from the roots of host plants, primarily composites (Asteraceae) such as sagebrush (Artemisia) and rabbitbrush (Ericameria). The plant produces a clustered arrangement of yellowish-purple to brownish tubular flowers emerging directly from the soil surface, giving the appearance of a dense cluster of floral spikes without any apparent above-ground vegetative structure. Germination is triggered by chemical signals from host roots. The species is considered an important component of native arid land ecosystems, though broomrapes are sometimes viewed as agricultural weeds where they parasitize crops. A. fasciculatum has not been formally evaluated for IUCN conservation status. The genus Aphyllon was recently split from the broader Orobanche to accommodate some New World species based on molecular evidence.