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..
Erect or ascending, 2°-4° high, glabrous or nearly so. Stipules subulate, deciduous; petioles 1'-2' long; leaflets ovate, blunt or acutish, somewhat glaucous beneath, the terminal one larger than the lateral and more or less rhomboid; racemes terminal, compound, slightly pubescent; bracts deciduous; calyx scabrous, the upper lobe entire or minutely 2-toothed, the 3 lower attenuate; flowers pink, s"-6" long; loment 3-4-jointed, the joints triangular, angled on the back, uncinate-pubescent; stipe 2"-3" long.
Hedysarum rhombifolium Ell. Bot. S. C. & Ga. 2: 216.
1824. Desmodium rhombifolium DC. Prodr. 2: 330. 1825. Desmodium floridanum Chapm. Fl. 102. 1860. Meibomia floridana Kuntze, Rev. Gen. Pl. 198. 1891. M. rhombifolia Vail, Bull. Torr. Club 19: 113. 1892.
Erect or ascending, 2°-3° high or more, uncinate-pubescent, simple or branched. Stipules subulate, taper-pointed; leaves ovate, often mucronulate, coriaceous, scabrous above, villous and reticulated beneath, 2'-3 1/2' long, the terminal rhomboid, the lateral ones often wanting; racemes terminal, simple or panicled, elongated, usually leafless; bracts minute, deciduous; calyx-lobes acute, the upper one 2-toothed; loment 2-5-jointed, the joints obliquely semi-rhomboid, rounded on the back, uncinate-pubescent; stipe often as long as the lowest joint.
In sandy soil and pine lands, Virginia to Florida, west to Alabama and Louisiana. May-Sept.
Hedysarum viridiflorum L. Sp. Pl. 748. 1753. Desmodium viridiflorum Beck, Bot. 84. 1833. Meibomia viridiflora Kuntze, Rev. Gen. Pl. 197. 1891.
Erect, rather stout, downy-pubescent, 2°-4° high. Stipules lanceolate, mainly deciduous; petioles 1/2'-1 1/2' long; leaflets broadly ovate, obtuse, rough above, densely velvety-pubescent beneath, 1'-3 1/2 long, the terminal one somewhat rhomboid; racemes compound, elongated, terminal, uncinate-pubescent; bracts deciduous; upper calyx-lobe minutely 2-toothed, the 3 lower ones attenuate; flowers purple, 3"-4" long; loment 2-4-jointed, the joints semi-rhomboid, uncinate, about 2" long; stipe about equalling the lower lobes of the calyx.
Dry woods, eastern Pennsylvania and southern New York to Florida, Michigan, Missouri, Arkansas and Texas. Aug.-Oct.