Schinus polygama Chilean pepper tree

Old Schinus polygama on Campus Drive. Sairus Patel, 6 Jan 2023

Schinus polygama fruiting on Lane B. Sairus Patel, 21 Aug 2022

This tangled shrub or small tree was planted as an ornamental in California and even occasionally used as a street tree, though it has long since vanished from planting lists. Remnants still survive at Stanford, usually along property edges and on the slopes of The Dish.

Its leaves are simple, not pinnately compound as in the other two pepper trees on campus, and release no peppery scent when crushed. When Linnaeus first described the genus in 1753, five of the six species he named were compound-leaved; however, most Schinus species in fact have simple leaves. The broader-at-the-tip leaf shape, together with the stiff spines at the ends of shoots, often lead to confusion with pyracantha. But the leaf undersides are green, rather than whitish, and the blades tend to lie flat rather than folding slightly along the midrib. It has also been confused with S. longifolia, a species virtually unknown in this country and one that lacks the downy leaf stalks one sees in S. polygama. A recent study proposes that the spiny, interlaced structure – described as a cage-like growth form – likely evolved as a deterrent to browsing mammals in its native Chilean haunts.

Small yellowish flowers emerge in the spring and summer, maturing into attractive tiny purple fruit.

An old, picturesque tree is on Campus Drive near the Anderson Collection. Others persist along property margins: a tangled thicket of trunks and branches, possibly campus’s largest, is on the right at 625 Mayfield Avenue. Another is clipped into a hedge at Lane B near Coronado Avenue. Younger ones, likely volunteers, appear near the periphery of Frenchman’s Park along Gerona Road south of Mirada Avenue. A thick-trunked specimen also survives on the northwest edge of Palo Alto’s Mayfield Park.

As with S. terebinthifolius, its name was changed from S. polygamus to S. polygama when a 2015 paper in Phytotaxa revealed the true gender of Schinus.

Schinus polygama leaves are simple, alternate and sometimes also fascicled and whorled. John Rawlings, ca. 2005

Name derivation: Schinus – Greek name for mastic tree (Pistacia lentiscus), which it resembles; polygama – having both imperfect (pistillate and/or staminate) flowers and perfect flowers on the same plants.