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 rose, rarely white, showy, over 1/2 in. long, from 1 to 4 on short, slender peduncles from among upper leaves. Calyx of 5 unequal sepals, of which 2 are wing-like and highly colored like petals. Corolla irregular, its crest finely fringed; 6 stamens; 1 pistil. Also pale, pouch-like, cleistogamous flowers underground. Stem: Prostrate, 6 to 15 in. long, slender, from creeping rootstock, sending up flowering shoots 4 to 7 in. high. Leaves: Clustered at summit, oblong, or pointed egg-shaped, 1 1/2 in. long or less; those on lower part of shoots scale-like.
Preferred Habitat - Moist, rich woods, pine lands, light soil.
Flowering Season - May - July.
Distribution - Northern Canada, southward and westward to Georgia and Illinois.
Gay companies of these charming, bright little blossoms hidden away in the woods suggest a swarm of tiny mauve butterflies that have settled among the wintergreen leaves. Unlike the common milkwort and many of its kin that grow in cloverlike heads, each one of the gay wings has beauty enough to stand alone. Its oddity of structure, its lovely color and enticing fringe, lead one to suspect it of extraordinary desire to woo some insect that will carry its pollen from blossom to blossom and so enable the plant to produce cross-fertilized seed to counteract the evil tendencies resulting from the more prolific self-fertilized cleistogamous flowers buried in the ground below. It has been said that the fringed polygala keeps "one flower for beauty and one for use"; "one playful flower for the world, another for serious use and posterity"; but surely the showy flowers, the "giddy sisters," borne by all cleistogamous species to save them from degenerating through close inbreeding, are no idle, irresponsible beauties. Let us watch a bumblebee as she alights on the convenient fringe which edges the lower petal of this milkwort. Now the weight of her body so depresses the keel, or tubular petals, wherein the stamens and pistil lie protected from the rain and useless insects, that as soon as it is pressed downward a spoon-tipped pistil pushes out the pollen through the slit on the top on the bee's abdomen. The stigmatic surface of the pistil is on the opposite side of the spoon, nearest the base of the flower, to guard against self-pollination. After the pollen has been removed, a bumblebee, already dusted from other blossoms, must leave some on the stigma as she sucks the nectar. Indeed, every feature possessed by this pretty flower has been developed for the most serious purpose of life - the salvation of the species.
Only locally common throughout a wide area, embracing the eastern half of the United States and Canada, is the Racemed Milkwort (P. polygama), whose small, purple-pink, but showy flowers, clustered along the upper part of numerous leafy stems, are found in dry soil during June and July. Like the fringed milkwort, this one bears many cleistogamous, or blind flowers, on underground branches, flowers that always set an abundance of fertile self-planted seed in case of failure to form any on the part of their showy sisters, which are utterly dependent upon the bee's ministrations. During prolonged stormy weather few insects are abroad.