Much like no. 1 [Lotus corniculatus L.], and not always sharply distinct exomorphically, but less robust and typically in drier, more difficult habitats; lfls mostly linear or lance-linear and 2.5-5+ times as long as wide; fls mostly (1)2-5 together; cal-tube 1.8-2.8 mm; cor 7-10(-12) mm, yellow, drying orange; 2n=12. Native of Europe, widely intr. in U.S., but more common in arid regions. June- Aug. (L. corniculatus var. tenuifolius)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.