Matricaria occidentalis

Valley mayweed

Family: Asteraceae · Type: annual · Native

Valley mayweed is a California native annual herb found in northern coastal and inner coastal ranges, Central Valley, San Francisco Bay Area, southern coastal California, Channel Islands, and western Mojave Desert in alkali flats, vernal pools, and salt marsh edges at elevations below 2,400 meters. Flowering from March to August, this plant produces white disk flowers in compact, nearly spherical heads up to 1.5 centimeters in diameter. Growing 15 to 45 centimeters tall with often branched stems toward the top, it forms a delicate, open structure. Its leaves are sessile, glabrous, and can reach up to 7 centimeters long, with a fine, feathery appearance. The fruit is distinctive, with angled surfaces and wide brown glands extending halfway down its length, topped with a two-lobed tip.

Habitat: Common. Undisturbed alkali flats, vernal pools, edges of salt marshes

Bloom period: Mar-Aug

Elevation: < 2400 m

Bioregions: NCoRO, CaRH, SNH, GV, n CCo, SnFrB, SCoRO, SCo, ChI, w DMoj

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.