Trifolium aureum is an annual or biennial herb, to 45 cm tall, taprooted, roots with nitrogen-fixing nodules formed by a symbiosis with Rhizobium bacteria typical of legumes (Raven et al. 1986). Stems much branched, appressed-hairy, young stems often dark red. First year plants sometimes spreading out in mats of many plants on lawns (personal obs.).
Leaves alternate, 3-parted, leaflets nearly stalkless (sessile), stipules triangular, tan-membranous, hairy, about as long as petioles.
Flowers yellow, bilaterally symmetrical, 0.5-0.7 cm long, pea-flower-shaped, persistent, turning brownish with age, calyx 2-lipped; flower heads dense, to 2 cm long, cylindrical; blooms June-Sept.
Fruit small dry pods enclosed in old calyx, with style attached and about as long as the pod which contins 1-2 seeds.
Wetland status: NL.
Frequency in NYC: Infrequent.
Habitat: Along roadsides, lawns, open areas.
Notes: Foliage eaten by rabbits and woodchucks, seeds eaten by numerous birds and small mammals (Martin et al. 1951).