Silver beach bur is one of the most common plants
found growing along the coastal sand dunes of Southern California. It
is a matted, many-stemmed perennial herb with brown to gray-canescent
procumbent branches up to 5' long covered with ± silky hairs.
The leaves are variable, simple, long-petioled, and in outline ovate,
rhombic to oblanceolate or widely triangular, and toothed to 3-pinnately
lobed. This is a mono-
ecious species with staminate and pistillate flowers
in separate heads on the same plant, the staminate flowers in dense
terminal spikes and the pistillate flowers crowded below. The staminate
heads are 25-50-flowered and each pistillate head contains a single
flower. The fruit is an ovoid, ± reddish-brown bur with 10-20+
awl-shaped spines with wide bases. Silver beach bur blooms from July
to November on coastal strand beaches and dunes to about 75' from Baja
north to British Columbia, and on San Clemente, Santa Catalina, San
Miguel and Santa Cruz Islands. These pictures were taken at Bolsa Chica.
Click here for Latin name derivations: 1) Ambrosia 2)
Pronunciation: am-BRO-zee-a sham-i-SEW-nis.
Click here for Botanical