T. subterraneum: annual; stem short, decumbent; leaflets obovate; heads lateral, stalked, few-flowered, the peduncles becoming lengthened after flowering, and the heads buried in the earth; flowers long and slender, almost white. - Dry pastures and heaths. Fl. May.
T. sufifocatum: annual; stems short, decumbent; leaflets obovate; heads dense, lateral, sessile; flowers minute, closely sessile, inconspicuous. - Sandy sea-coasts. Fl. May to July.