Achillea millefolium
(Asteraceae)
The utilitarian yarrow should not be considered a weed. In Sweden, it is used as a substitute for hops in brewing beer. In dry areas (like California), it can be a lawn substitute. It does not require irrigation and tolerates mowing. When left unmowed the 1-2 foot feathery-leaved stems produce a flat cluster of flowers, consisting of both ray and disk flowers.
DISTRIBUTION: Many habitats throughout Calif. except the deserts; < 3500 m.