I"ve been an amateur botanist since circa 1997 with a special interest in California native plants. A corollary passion of mine is birding and, like many fellow birders, I keep a Life List of all the bird species that I've observed in my lifetime. So I thought, why not also create a life list for plants I've seen in the field? In addition to California natives, I've also included a smaller list of plants that I've observed and photographed in their native habitats outside of the U.S.
From Wildflowers of Britain & Northern Europe by Andrew Cleave & Paul Sterry:
Description: Downy perennial herb with trefoil leaves, each narrow leaflet usually bearing a white crescent pattern. Small, pinkish-red flowers are borne in unstalked, globular heads, sometimes in pairs, with a pair of short-stalked leaves below the head.
Flowering period: May-October
Habitat: Wide range of grassland habitats, also in waste places along roadsides. Very widespread and often abundant.