chamise
Adenostoma fasciculata

Family: Rosaceae.

Type: Evergreen shrub.

Branching: Leaves are clustered, but branches are alternate.

Leaves: Very small and needle-like, in little bundles (which is the meaning of fasciculate). In spring, the leaves are often sticky and coated with resin. As with other chaparral plants with resinous leaves (such as yerba santa), the resin reduces water loss.

Twig: See below; not commented upon.

Fruit & Flower: The reddish tips of branches are dried fruits and the remnants of flowers. In fall chamise gives the driest areas of the chaparral a reddish tinge. Flowers are white in the spring (see this photo from the U.S. Bureau of Reclamation of chamise in bloom).

Miscellaneous: Chamise dominates the driest, hottest slopes of chaparral. Several traits make it the ultimate xeric chaparral plant. Many chaparral plants are obligate seeders: they reproduce only by seed, and are dependent upon fire (either its heat or the release of chemicals) for germination. Many other chaparral plants are sprouters: they will sprout from the base when fire comes through. Chamise is somewhat unique in being both a seeder and a sprouter; when fire occurs, it reproduces in two different fire-dependent ways simultaneously.

The resin in chamise's leaves washes off and collects in the soil, often forming a fairly impermeable layer that increases runoff by creating a barrier to water percolation through the soil. Chamise's resin is also particularly flammable, and promotes fire in the chaparral; chamise will basically explode when it burns, even producing a crater in the ground. The burning of chamise resins releases chemicals that are a cue for the seeds of some other chaparral species to germinate.

The last two photos are from Jasper Ridge, and show, to my eye, a somewhat different morphology of sparser growth and longer leaves.