Quercus palmeri Palmer oak

Quercus palmeri with acorn cup golden and flared at the rim, Hualapai Mountain Park, Arizona. Acorn nuts have not been seen on Stanford’s specimens. Sairus Patel, 5 Sep 2022

Quercus palmeri at Jasper Ridge Biological Preserve. Sairus Patel, 11 Oct 2023

A small group of this shrubby evergreen oak quietly grows southeast of Searsville Lake at Jasper Ridge Biological Preserve, in a spot known as Buckeye Alley (map pin). Remarkably rare in the region, its nearest reported occurrence is the Sunol Regional Wilderness in the East Bay. Far to the south, in the Jurupa Mountains, a clonal colony of the species – estimated to be at least 13,000 years old – drew national attention in 2024, when debate centered on how near a mixed-use development might be allowed. The approved buffer was 550 feet.

Closely allied to Q. chrysolepis, indeed once considered a subspecies of it, Palmer oak may be distinguished by its fewer secondary leaf veins (10–14, compared to 24 or more in canyon live oak) and by its rigid, rather than flexible, small twigs. The leaf margins are viciously spined, and the pale undersides are lightly dusted with golden hairs. Only developed but empty acorn cups have so far been found on our specimens, their rims wavily flared as often seen in the species; the nuts themselves are absent.

Illustrations: Jasper Ridge photos (as Q. chrysolepis, but now considered Q. palmeri).