T. pratense: stem erect, slightly branched, 1-2 feet high; radical and lower leaves linear, keeled, dilated at the base, glabrous, slightly glaucous; peduncles long, thickened at the summit, each with a single head of yellow flowers; involucral bracts narrow-lanceolate; florets sometimes not half as long; achenes long, striate, the slender beak as long as the achene itself, the hairs of the pappus long and very feathery. - Yellow Goat's-beard. - Meadows and rich pastures. Fl. June.
T. porrifolium resembles the last, but is generally of more luxuriant growth, the peduncles more thickened at the top, the involucres longer in proportion to the florets, and the beak of the achenes and pappus longer. It also has deep violet or purple flowers.