Fraxinus ornus flowering ash

Unusual among ashes for its showy, fragrant white flowers, flowering ash has four narrow, strap-like petals per flower, giving an effect reminiscent of Chionanthus. The leaves have 5–9 clearly stalked leaflets that can be quite broad. The species is rare locally. One rises through the tangle of trees around the drainage ditch near the southeast corner of Roth Way and Palm Drive. Its leaves turn a peach-tinged yellow in autumn, somewhat like those of Autumn Purple ash, but much later in the season. Another tree, behind Building 50 in the Outer Quad, was removed around 2011. In Palo Alto, one grows on Harriet Street, just around the corner from 1102 Channing Avenue. More examples of this Mediterranean native should be tried on campus.

In Sicily, F. ornus as well as F. angustifolia have long been cultivated for manna, a sweet substance obtained by making incisions in the bark and allowing the exuding phloem sap to harden in the air. Rich in mannitol, a sugar alcohol, manna has long been used as a mild laxative. A 2019 study reported that rising manna prices were making the traditional cultivation of these ashes economically viable again. Ornus is a classical Latin name for a wild ash, often identified with the manna ash.