Lyonothamnus floribundus subsp. aspleniifolius
Santa Cruz Island ironwood

Rosaceae (rose family)
California Channel Islands
Lyonothamnus floribundus subsp. aspleniifolius blooming in early summer on Bodoin Street. Sairus Patel, 7 Jun 2018
Lyonothamnus floribundus subsp. aspleniifolius leaf. From Trees of Stanford and Environs, Ronald Bracewell

Native to the islands off the Southern California coast, Santa Cruz Island ironwood is a dramatic small tree with fernlike foliage and curiously peeling bark in strips of contrasting browns and grays, interesting to feel. The compound leaves have about five narrow leaflets, each deeply sculpted into triangular lobes. Large clusters of small white flowers are noticeable in summer and remain hung up in an untidy manner for months. The fruit is a ¼-inch woody capsule containing two pairs of seeds. The dense red wood is suitable for small projects.

Uncrowded specimens can be seen in the Stanford Avenue greenbelt between Santa Fe Avenue and Sonoma Terrace bike paths, and there are about a dozen on the south side of Bowdoin Street between Pine Hill Road and Stanford Avenue. A group is east of Encina Hall, at the northwest corner of the Eating Clubs; a single tree is at Encina’s northeast corner.

It is often misleadingly called Santa Catalina Island ironwood, or some variant thereof. That epithet should be reserved for the rare L. floribundus subsp. floribundus, which has simple, undivided leaves and occurs only on Santa Catalina Island. Subspecies aspleniifolius is restricted to Santa Cruz, San Clemente and Santa Rosa Islands. The fossil record does indicate that Lyonothamnus grew in many parts of the western United States in the Tertiary period.

Illustrations: leaf.

Name derivation: Lyonothamnus – After W. S. Lyon, who discovered it in 1884 and Greek thamnos (a shrub); floribundus – profusely flowering; aspleniifolius – with leaves like Asplenium.

About this Entry: The main text of this entry is from the book Trees of Stanford and Environs, by Ronald Bracewell, published 2005. Sairus Patel added the note on common names, ssp. floribundus, and provenance details Jul 2018 (Jepson 2, Griffin & Critchfield).