Trifolium dubium is an annual herb, much like T. campestre, to 40 cm tall.
Leaves alternate, 3-parted, terminal leaflet stalk barely 0.1 cm long.
Flowers yellow, pea-flower shaped, to 0.3 cm long; flower heads rounded, to 1 cm wide with 5-15 flowers; blooms April-Oct.
Fruit a very small dry pod.
Wetland status: NL.
Frequency in NYC: Very infrequent.
Habitat: Dry, open soil.
Notes: Often a lawn weed (personal observation).