Arctostaphylos hookeri var. ravenii
|Presidio manzanita, Raven's manzanita|
The following Participating Institutions are custodians for this species in the CPC National Collection:
University of California Botanical Garden
The conservation of Arctostaphylos hookeri var. ravenii is partially sponsored.
Holly Forbes contributed to this Plant Profile.
Raven's manzanita is a low-growing evergreen shrub with urn-shaped white to pink flowers. It was rediscovered by Peter Raven when he was a young boy in San Francisco in 1952 (it was described as subspecies ravenii in 1968). There is one naturally occurring plant left in its native habitat, located on a slope facing the Pacific Ocean in the San Francisco Presidio. This area is now managed by the Presidio Trust, a government corporation.
Distribution & Occurrence
This species grows best on slightly acidic, serpentine soils that occur in isolated outcrops.
|One known wild plant is maintained in an area on the Presidio Army Base in San Francisco, CA. Additional identical clones have been planted nearby and are also in cultivation at the University of California Botanical Garden at Berkeley and in other gardens (USFWS 2001).|
Conservation, Ecology & Research
The flowers are apparently self-compatible, producing seeds of less than 20% viability, although further study is needed.
Habitat loss due to urban development
Competition with other species (shading)
Fungal pathogen(s) (including twig blight)
Genetic analysis of open-pollinated seed generated plants at the UC Botanical Garden is needed to determine their status as pure strains or hybrids.
Adams, J.E. 1935. A Systematic Study of the Genus Arctostaphylos. Berkeley: Berkeley Press.