Trifolium repens L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Perennial; stems creeping, sending up long-petioled lvs and long- peduncled heads; stipules connate beyond the level of adnation to the petiole to form a pale, tubular- amplexicaul sheath, but the tips separate; lfls broadly elliptic to obovate, rounded to retuse at the summit, 1–2 cm; fls 7–11 mm, distinctly pedicellate; cal glabrous, the tube 1.8–3 mm, the nerves leading to the acute sinuses sharply defined and ending in a purple spot; cal-lobes narrowly triangular, acuminate, unequal, the longest about equaling the tube; cor white or tinged with pink, the standard elliptic-obovate, rounded at the tip, exceeding the obtuse wings; 2n=32 (64). Native of Eurasia, commonly planted and escaped in lawns and roadsides throughout most of temperate N. Amer. All summer.