Pineapple Weed, Rayless Chamomile: Matricaria discoidea (Synonyms: Chamomilla suaveolens; Santolina suaveolens) - Introduced annual of disturbed places.
Western Chamomile, Valley Mayweed, Western Pineappleweed: Matricaria occidentalis (Synonym: Chamomilla occidentalis) - Native annual of undisturbed moist places.