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..
T. medium L. Amoen. Acad. 4: 105. 1759.
Closely resembling the preceding species. Stem sometimes conspicuously zigzag, but often straight, finely pubescent or glabrate. Stipules lanceolate; leaflets lanceolate or oblong, not spotted, frequently entire except for the projecting tips of the veins; heads always more or less peduncled; flowers very nearly sessile; corolla 6"-7" long, bright purple; calyx-tube nearly glabrous, the teeth slightly pubescent.
In fields and waste places, Nova Scotia, Ontario and Massachusetts. Erroneously recorded from Missouri and elsewhere. Adventive or naturalized from Europe. Native also of Siberia. Cow- or giant-clover. Pea-vine clover. Summer.
Trifolium Beckwithii Brewer; S. Wats. Proc. Am. Acad. 11: 128. 1876.
Perennial, glabrous throughout; stems rather stout, erect or nearly so, straight, 6'-18' high. Basal leaves on long petioles; stipules narrow, acute, 1' long or less; leaflets oblong, or somewhat oblanceolate, obtuse, denticulate, 9"-2' long; heads long-peduncled, globose, 1'-1 1/2' thick; flowers purple or purplish, 6"-9" long, very short-pedicelled, the lower at length re-flexed; calyx-teeth glabrous, linear-subulate, the longer nearly equalling the tube; pod 2-6-seeded.
Eastern South Dakota, probably introduced from farther west. Native from Montana to California. May-June.
Perennial from a long large root, diffusely branched at the base, the branches prostrate, pubescent. Leaflets linear, narrowly lanceolate or oblanceolate, 5"-20" long, obtuse or cuspidate, serrate-dentate, glabrous above, more or less silky beneath, conspicuously veined; flowers in globose heads about 1' in diameter, whitish, crowded, the slender pedicels 1"-2" long; standard emarginate-mucronate, striate; calyx silky, the teeth long, subulate.
Slopes of Cate's Mountain, Greenbrier Co., W. Va. June.
Trifolium reflexum L. Sp. Pl. 766. 1753.
Annual or biennual, pubescent, ascending, branching, 10'-20' high. Leaves long-petioled; stipules ovate-lanceolate, acuminate, foliaceous, few-toothed or entire, 8"-12" long; leaflets all from the same point, short-stalked, oval or obovate, cuneate at the base, obtuse or emarginate at the apex, denticulate, 5"-12" long; heads peduncled, dense, globose, 1' in diameter or more; flowers 5"-6" long, all on slender pedicels, at length 3"-4" long and reflexed; standard red, wings and keel nearly white; calyx-teeth linear-subulate, shorter than the corolla, finely pubescent; pods 3-6-seeded.