Lotus corniculatus is a short-lived perennial form a taproot up to 1 m long, colonial from sprouting buds on numerous lateral roots that form a fibrous mat. Can resprout from detached root segments. Stems multiple, often prostrate to reclining, to 60 cm, becoming woody, forming adventitious roots when in contact with soil, younger stems 4-sided (Turkington and Franko 1980).
Leaves compound, 5 leaflets, 0.5-2 cm long cm long, 0.2-0.9 cm wide, elliptic to egg-shaped, the two basal, subsessile (stalkless), stipule-like, separated from crowded upper 3 leaflets.
Flowers bright, clear yellow, becoming orange marked with red, 1-1.6 cm long, bilaterally symmetrical, pea-flower-shaped; inflorescence of umbrella-shaped clusters of 4-8 flowers on stalks to 10 cm long in upper axils; blooms June-Aug.; pollinated by large bumblebees, needs cross pollination (Turkington and Franko 1980).
Fruit becoming dry, a pod to 3 cm long, 0.3 cm wide, cylindrical, becoming dull black, in palmately arranged clusters at right angles to stalk, dispersed by explosive dehiscence as pods twist spirally and also by passing through digestive system of cattle and birds; seeds, about 20 per pod, round, ca 1 cm wide. Seed viability decreases with age to about 10% after 9 years (Turkington and Franko 1980).
Wetland status: FACU-.
Frequency in NYC: Occasional.
Origin: Europe and Asia.
Habitat: Open, disturbed areas, fill, roadsides, lawns.
Notes: An agricultural plant used for cattle feed. High nitrogen production; like other legumes, roots form nodules associated with nitrogen fixing bacteria, Rhizobium japonicum (Turkington and Franko 1980; USDA, NRCS 2006). Plants produce a cyanogenic glucoside that may deter grazing by snails (Kingsbury 1964). Prefers moist soil pH 6.5, tolerates soil pH 4.5-7.9. Tolerates partial shade, drought, saturated soils, salt. A long-day (short night) plant, requires 16 hours daylight for maximum blooming. Attacked by the Hemiteran (leaf bug) Lygus lineolaris. Also attacked by a witch’s broom virus, several fungi, including Sclerotina trifolium and Fusarium solani and a number of nematodes (Turkington and Franko 1980).