(1911)  Page(s) 206.  
 
R. spithamaea Wats. var. sonomensis Jepson. Sonoma Rose. Branches several from the base, erect, mostly simple, 9 to 12 in. high, densely armed with stout straight or slightly recurved prickles.; leaflets 5, broadly ovate, 4 to 8 lines long, serrate, with teeth minutely glandular-denticulate; flowers small, several in a corymb; hips globose, 3 to 5 lines broad; calyx-lobes ovate-lanceolate, glandular hispid, rather closely erect in fruit. Rare montane species, on high dry slopes: Sonoma Co., Greene; Mt. Tamalpais, Jepson; Saratoga, Santa Clara Co., Davy.