Ranunculus acris is a perennial herb to 1 m tall, from short root stock, spreading, most parts hairy.
Leaves alternate, stalks of basal leaves elongate, blade rounded in outline, deeply palmately 3-lobed, lobes divided, lobes narrowed at base, leaves reduced upwards.
Flowers yellow, showy, 2 cm wide, petals 5, 0.7-1.5 cm long, 0.6-1.4 cm wide, widest across top, sepals 5, narrow, 0.4-0.7 cm long, pistils and stamens numerous, pistils in a tight, round cluster, styles very short, slightly hooked, May-Sept, mostly pollinated by bees, also visited by butterflies, beetles, and flies, somewhat self-fertile (slight agamospermy) (Mulligan and Kevan 1973; Wyatt 1983).
Fruit dry achenes in a rounded head, smooth, flattened, style curved over forming a beak.
Wetland status: FACW.
Frequency in NYC. Infrequent. A widespread herb, probably more abundant than indicated here (USDA, NRCS 2009).
Habitat: Wet to upland meadows, roadsides, open areas.
Note: Contains the toxic oil protoanemonin (Kingsbury 1964).