Stinkweed, Dittrichia graveolens, Family: Asteraceae.

Other names: Stinkwort, Camphor Inula, Cape Khakiweed.

An aggressive invader, not native to North America; origin uncertain. Widespread inn S. Europe, Asia and Africa.
In California, its range is currently limited to the Bay Area and central region;
in eastern North America it is found only in NY, NJ, and CN.

A very similar plant -- possibly this one -- is commonly seen along freeway shoulders in the South Bay.

Specimen found at Patterson Ranch, Santa Clara County. Thanks to Doreen Smith for ID.