Encyclopedia of Stanford Trees, Shrubs, and Vines

Casuarina cunninghamiana. RIVER SHE-OAK. Victoria, New South Wales, Queensland
CASUARINACEAE (Casuarina family)

Superficially resembling pines because of their needles, the casuarinas also bear small cones and form beds of dry needles resembling the mat under a pine tree. Their dark-red tough wood is responsible for the occasional name beefwood, while the wide medullary rays suggested the name oak. Though the timber was shipped to Britain, it was not equal to oak imported from Britain; hence the prefix 'she-' (sorry ladies, but we are talking about 1800). The wood was used in the past for making boomerangs and clubs. Small red flowers on female trees make it clear that something unusual is going on and examination of the needles with a lens reveals tiny leaves in the form of teeth surrounding the needles at junctions that are clearly visible to the naked eye. River she-oak has nine leaf teeth, plus or minus two, the needles are 1/50 inch in diameter with 1/4-inch segments, the cones are about 1/4 inch in diameter but may be larger, and the outside surface of the valves is smooth. To count the teeth it helps to pull the needle apart at a joint. Evidently the tree's photosynthesis function has been taken over by the chlorophyll in the stems. The cones are barrel shaped and formed of rings of bivalves, the number in each ring being about the same as the number of leaf teeth. The arrangement does not follow the spiral plan of the conifers. Each bivalve opens meridionally to release one winged seed.

In its natural habitat it grows in river beds and on their banks. In New South Wales, its principal native habitat, where it grows to 100 feet high and 4 feet in diameter, river she-oak is a protected species on account of growing on and stabilizing river banks. Nine specimens of casuarina can be seen growing in harsh conditions on the south side of Roth Way; even so, two have reached 60 feet in height. Another group of nine, males and females, is on Lasuen Street midway between Campus Drive East and Arboretum Road and there are a dozen nearby on the closed road that bisects the intersection of Lasuen Street and Campus Drive. There are also a dozen on the south side of Campus Drive West between Lomita Drive and Old Anatomy, seemingly the remnant of a double row. The casuarina is a battler, it has survival value in neglected areas, and it is easy on the eye.

The name Casuarina was given by Linnaeus in 1759 because of resemblance to the plumage of the cassowary, a 5-foot high, shy flightless bird native to New Guinea, northeast Australia, and some adjacent islands. The species name refers to Alan Cunningham, a colorful botanical explorer of the early 1800s, who is memorialized by an obelisk in the Royal Botanical Gardens, Sydney.

Field Guide to Identify the Common Casuarina (Australian Pine) Species in Florida by William S. Castle offers excellent field identification advice.

Illustrations (links open new windows): Silhouettes from Trees of Stanford & its Environs

Additions/Revisions:

Name derivation, genus | species

Related material: Canopy Trees for Palo Alto Tree Library; Stanford Grounds Plant Information Sheet. List No.5, p.5

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