Acacia dealbata · silver wattle · Tasmania, Victoria, New South Wales, Queensland
Acacia decurrens · green wattle · New South Wales, Queensland

Fabaceae (pea family)
Acacia dealbata (trunk on left), Lomita Drive. Sairus Patel, 16 Feb 2018
Leaf of Acacia dealbata, west side of Lake Lagunita. John Rawlings

The brilliant yellow displays in February and March, which distinctly precede the coming of spring and add color to winter’s end, are mainly from these species.

The feathery leaves are bipinnately compound: they are divided into a dozen or so pinnae each with three dozen or so pinnules about ⅙ inch long. Both species have raised glands on the upper surface of the leaf’s main axis at the junction of each pair of pinnae, as shown in the illustration.

At the point of attachment to the branch, the leaf stalks of green wattle run on as definite ridges on the branch. Green wattle also has a rough, dark or black trunk. The twigs of silver wattle are finely hairy, and more or less angular without wings. Many of the campus trees do not exhibit the silvery-gray foliage of silver wattle, but neither do they possess the prominently ridged stems and dark trunk of green wattle.

There is one on Campus Drive at the southeast corner with Lomita Drive. Substantial numbers can be found in the area of Frenchman’s and Gerona Roads.

A large leaning specimen ws on Governor’s Avenue where it makes a corner at Lake Lagunita; it was no longer present in February, 2018.

Silver wattle is an invasive weed in Bear and San Francisquito creeks in Jasper Ridge Biological Preserve and along other campus waterways.

Acacia dealbata compound leaf and fruit. John Rawlings

Illustrations: Jasper Ridge plant photo archive.

Name derivation: Acacia – Greek akis, a sharp point; dealbata – whitened (young shoots and leaves).

About this Entry: The main text of this entry is from the book Trees of Stanford and Environs, by Ronald Bracewell, published 2005. The sentence “I have concluded that I cannot tell one from the other and look forward to being instructed” was replaced by some notes on the glands and twigs by John Rawlings (ca. 2010). Edits and note on Governor’s Ave specimen removal Feb 2018 (SP).