Hiking across a remote meadow, I suddenly find myself in a knee-high field of daisies. This is the invasive oxeye daisy (Leucanthemum vulgare), a striking flower with stark white petals around a yellow center.
This bloom was introduced from Europe and is now widespread throughout Marin and much of California. It has a cousin, Shasta daisy, which is less common and has (very slightly) larger flowers and leaves. Oxeye daisy is a moderately problematic invasive, growing so densely in places that it excludes other native vegetation. It also is known for giving cows’ milk an unpleasant taste if they eat it.