Etymology: Trifolium: from tres for three; folium for leaves
Plants: erect, annual, 4"-16" tall forb with many branches; stems fuzzy
Leaves: pinnately 3-parted, leaf and end leaflet stalked
Flowers: yellow, 5-parted, 1/8"-1/4" long, keel (top petal) grooved, calyx 2-lipped; inflorescence a dense, round to cylindrical head of 20-30 flowers; blooms May-Sept.
Habitat: disturbed sites
Conservation Status: Introduced - naturalized
USDA Plants Database: Federal Distribution and detailed information including photos USDA Agricultural Research Service (ARS): Images of seeds, fruits, embryos, etc. Dan Tenaglia's The Missouri Flora: Fabulous photographs; detailed descriptions; color and leave arrangement key. David G. Smith's "Delaware Wilflowers": Beautiful photographs; descriptions Illinois Wildflowers: Wonderful photographs; detailed descriptions; color and leaf arrangement key