Ceanothus impressus var. nipomensis
in M. van Rensselaer and H. McMinn, Ceanothus, 219, figs. 12, 13. 1942.
Shrubs, open, not intricately branched, 1.5–3 m. Leaf blades ± flat to cupped, widely elliptic to suborbiculate, 11–20(–25) × 7–17(–20) mm, margins thick to weakly revolute, teeth evident adaxially; veins moderately furrowed.
Phenology: Flowering Feb–May.
Habitat: Sandy or gravelly, open sites, chaparral, oak woodlands.
Elevation: 50–200 m.
Discussion
Variety nipomensis occurs primarily on Nipomo Mesa and the eastern San Luis Range of southern San Luis Obispo County. R. F. Hoover (1970) regarded it as derived from hybridization between var. impressus and Ceanothus oliganthus. However, there is little evidence to indicate that populations of these two taxa overlap in geographic and ecological range. We treat var. nipomensis as part of C. impressus, based on its furrowed veins and fruit morphology. Urbanization has reduced the number of known populations to a relatively few, scattered localities.
Variety nipomensis is in the Center for Plant Conservation’s National Collection of Endangered Plants.
Selected References
None.