Heteromeles arbutifolia
Small, dark green trees with clusters of white flowers are scattered here and there across the hillsides. This is toyon (Heteromeles arbutifolia). It will truly come into its own in a few months, when clusters of brilliant red berries begin to ripen. Toyon is also called “christmas berry” for these cheerful December fruit, which once were sold as a local substitute for similarly colored holly sprigs.
Don’t get any ideas about collecting your own–it’s now illegal to harvest wild toyon. This species is often a part of the scrubby chaparral community, but you can also see it in oak woodlands and other forests and shrublands across the state. The berries are described as having a “sweet and spicy” flavor, and a tea made from the leaves was used for irregular menses, aches, pains, stomachaches, and to wash wounds. Californians once ate the fruit regularly–roasted, toasted and fresh. Spanish settlers made a drink from the bark, and Channel Island fishermen used it to tan their fishing lines. 
Flowers Of Marin 