This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Trifolium repens L. Sp. Pl. 767. 1753.
Perennial, glabrous, or with a few scattered hairs, branching at the base, the branches creeping, often rooting at the nodes, 4'-12' long. Leaves long-petioled; stipules ovate-lanceolate membranous, acute, 2"-5" long; leaflets all from the same point, short-stalked, obovate, emarginate or obcordate, broadly cuneate at the base, denticulate, 4"-9" long; heads globose, long-peduncled; flowers white, 3"-5" long; pedicels 1"-2" long, finally reflexed; corolla 2-3-times as long as the calyx; calyx-teeth acuminate, somewhat shorter than the tube; pod about 4-seeded.
In fields, waste ground and open places, very common throughout our area and in the southern States. Also in the Northwest. Naturalized from Europe, or perhaps native in the extreme north. Naturalized in the mountains of Jamaica and in Bermuda. Native also of Siberia. Widely distributed in all temperate regions: Leaflets sometimes 4-9. Heads occasionally proliferous. Flowers sometimes pinkish. English names, sheep's gowan, honeystalks, lamb-sucklings, and sometimes shamrock. May-Dec.