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, remarkably rare in the region, quietly grows southeast of Searsville Lake at Jasper Ridge, in a spot known as Buckeye Alley. It is guarded by the flaming swords of poison oak and chamise that rise in dense mounds, choking the pathways leading to it.

Palmer oak is closely allied to Q. chrysolepis — indeed, it was once considered a subspecies of it — and 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 group was in fact initially identified as Q. chrysolepis in 1973; closer examination around 2022, applying these distinctions, revealed it to be Q. palmeri instead.

The leaf margins are viciously spined, while the pale undersides are lightly dusted with golden hairs. The rims of the golden acorn cups are flared and wavy, as often seen in the species. No fertile acorns have yet been noted on our roughly 10 specimens, which range from 6 to 20 feet tall; the nuts seem to abort before reaching maturity.

The nearest reported Palmer oaks are in the Sunol Wilderness Regional Preserve 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 close a mixed-use development might be allowed; the approved buffer was ultimately set at 550 feet.

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