Quercus coccifera
kermes oak
This bristly evergreen Mediterranean oak was formerly prized, even named, as the bearer of coccum (meaning grain or seed): pea-sized balls that were carefully harvested, dried, and used to produce a crimson dye. Remarkably, these rounded objects, grain-like when dried and shriveled and once thought to be growths or galls, are in fact the swollen bodies of pregnant female kermes, sap-sucking scale insects attached to the twigs. The dye itself is also called kermes, deriving via Arabic qirmiz and giving rise to crimson. Cochineal, obtained in the New World from a different scale insect, eventually displaced kermes and remains the dominant natural crimson dye today. Also see the molluscan origin of Tyrian purple in the Phoenix dactylifera entry.
After such a colorful introduction, the large shrubby specimens at Stanford may seem modest, until one notices the sizeable acorns, often an inch and a half long and an inch wide. Their bristly cups enclose about half the nut. The leaves are tough with toothed margins, like those of coast live oak, but smaller and flat, with pairs of veins neatly extending from the midrib towards the edge.
See two immense, prickly mounds of kermes oak intertwined with coast live oak along the path just northeast of the vernal pool in the Arboretum. Another grows at the base of the Mt. Tabor oak farther along the path toward Palm Drive. Two more, pruned into small trees, are near the south corner of Serra Street and El Camino Real. The species also features in Canopy’s 2007–2008 East Palo Alto Tree Initiative plantings along the Highway 101 soundwall, for example on either side of the pair of primrose trees at West Bayshore Road at Dumbarton Avenue. All were grown from acorns gathered from trees in the Shields Grove at UC Davis, labeled Q. calliprinos, the more arborescent eastern Mediterranean form, now often subsumed within Q. coccifera.
About this Entry: Authored Sep 2017 by Sairus Patel as Q. calliprinos. Updated Jul 2026 (SP).
