Is Ribes malvaceum, chaparral flowering currant, Marin’s rarest common shrub?

by Doreen Smith

Though mentioned as occurring in two local sites by Howell’s Marin Flora, it took me many years to locate even one plant of Ribes malvaceum. Maybe you have discovered others in Marin County? The site where we found it was not one of the given-by-Howell locations, but in the coastal chaparral of the Marin Headlands. The plant was (hope it still survives) on the upper end of the Bobcat trail/fire road, next to the only willow thicket.

It may be an even earlier-flowering species than the more common flowering currant, Ribes sanguineum var. glutinosum. Ribes malvaceum prefers the dry chaparral, whereas Ribes sanguineum prefers moist coastal habitats. The appearance of the leaves also differs: the upper surface is fissured and rough-hairy (malvaceum) or not so (sanguineum). Another distinction is an obscure feature of the flowers: the style is hairy in Ribes malvaceum, whereas it is glabrous in Ribes sanguineum.

Marin’s Ribes malvaceum flowers look morphologically like those of the Mt. San Bruno shrubs, but differ in appearance from those of the Mt. Diablo population. However, the Jepson Manual says they are the same subspecies, Ribes malvaceum var. malvaceum.

Photos by Vernon Smith

Ribes malvaceum chaparral currant

Ribes sanguineum var glutinosum