This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flowers - Purplish pink or violet, veined, the butterfly-shaped ones having standard petal, wings, and keel, clustered at end of peduncles; the minute flowers lacking a corolla, nearly sessile. Calyx of 5 slender, nearly equal lobes. Stems: Prostrate, trailing, or sometimes ascending, woolly or downy, leafy.
Preferred Habitat - Dry soil; open, sandy places.
Flowering Season - August - September.
Distribution - Massachusetts to the Gulf, and westward to the Mississippi.
Springing upward from a mass of clover-like leaves, these showy little blossoms elevate themselves to arrest, not our attention, but the notice of the passing bee. As the claw of the standard petal and the calyx are short, he need not have a long tongue to drain the nectary pointed out to him by a triangular white mark at the base of the banner. Now, as his weight depresses the incurved keel, wherein the vital organs are protected, the stigma strikes the visitor in advance of the anthers, so that pollen brought on his underside from another flower must come off on this one before he receives fresh pollen to transfer to a third blossom. At first the keel returns to its original position when de-presssed; later it loses its elasticity. But besides these showy flowers intended to be cross-fertilized by insects, the bush clovers bear, among the others, insignificant-looking, tightly closed, budlike ones that produce abundant self-fertilized seed. The petal-iferous flowers are simply to counteract the inevitable evils resulting from close inbreeding. One usually finds caterpillars of the "dusky wings" butterfly feeding on the foliage and the similar tick trefoils which are its staple. At night the bush clover leaves turn upward, completely changing the aspect of these plants as we know them by day. Michaux named the group of flowers for his patron, Lespedez, a governor of Florida under the Spanish regime.
Perhaps the commonest of the tribe is the Violet Bush Clover (L. violacea), a variable, branching, erect, or spreading plant, sometimes only a foot high, or again three times as tall. Its thin leaves are more elliptic than the decidedly clover-like ones of the preceding species; its rose-purple flowers are more loosely clustered, and the stems are only sparingly hairy, never woolly.
On the top of the erect, usually unbranched, but very leafy stem of the Wand-like Bush Clover (L. frutescens), the two kinds of flowers grow in a crowded cluster, and more sparingly from the axils below. The clover-like leaflets, dark green and smooth above, are paler and hairy below. Like the rest of its kin, this bush clover delights in dry soil, particularly in open, sandy places near woods of pine and oak. One readily distinguishes the Slender Bush Clover (L. Virginica) by the very narrowly oblong leaves along its wand, which bears two kinds of bright rose flowers, clustered at the top chiefly, and in the axils.
Yellowish-white flowers, about a quarter of an inch long, and with a purplish-rose spot on the standard petal to serve as a pathfinder to the nectary, are crowded in oblong spikes an inch and a half long or less on the Hairy Bush Clover (L. hirta). The stem, which may attain four feet, or half that height, is usually branched; and the entire plant is often downy to the point of silkiness.
Dense clusters of the yellowish-white flowers of the Round-headed Bush Clover (L. capitata) are seated in the upper axils of the silvery-hairy, wand-like stem. Pink streaks at the base of the standard petal serve as pathfinders, and its infolded edges guide the bee's tongue straight to the opening in the stamen tube through which he sucks.