Distribution - New Brunswick westward to Nebraska, south to Gulf of Mexico.
Amphicarpaea ("seed at both ends"), the Greek name by which this graceful vine was formerly known, emphasizes its most interesting feature, that, nevertheless, seems to many a foolish duplication of energy on Nature's part.Why should the same plant bear two kinds of blossoms and seeds? Among the foliage of low shrubbery and plants in shady lanes and woodside thickets, we see the delicate, drooping clusters of lilac blossoms hanging where bees can readily discover them and, in pilfering their sweets, transfer their pollen from flower to flower.But in case of failure to intercross these blossoms that are dependent upon insect help to set fertile seed, what then? Must the plant run the risk of extinction? Self-fertilization may be an evil, but failure to produce seed at all is surely the greatest one.To guard against such a calamity, insignificant looking flowers that have no petals to open for the enticing of insects, but which fertilize themselves with their own pollen, produce abundant seed close to the ground or under it.Then what need of the showy blossoms hanging in the thicket above? Close inbreeding in the vegetable world, as in the animal, ultimately produces degenerate offspring; and although the showy lilac blossoms of the wild peanut yield comparatively few cross-fertilized seeds, these are quite sufficient to enable the vine to maintain those desired features which are the inheritance from ancestors that struggled in their day and generation after perfection.No plant dares depend upon its cleistogamous or blind flowers alone for offspring; and in the sixty or more genera containing these curious growths, that usually look like buds arrested in development, every plant that bears them bears also showy flowers dependent upon cross-pollination by insect aid.
The boy who "Drives home the cows from the pasture Up through the long shady lane"knows how reluctantly they leave the feast afforded by the wild peanut.Hogs, rooting about in the moist soil where it grows, unearth the hairy pods that should produce next year's vines;hence the poor excuse for branding a charming plant with a repellent folk-name, VIOLETS(Viola) Violet family Lacking perfume only to be a perfectly satisfying flower, the COMMON, PURPLE, MEADOW, or HOODED BLUE VIOLET (V.obliqua; V.
cucullata of Gray) has nevertheless established itself in the hearts of the people from the Arctic to the Gulf as no sweet-scented, showy, hothouse exotic has ever done.Royal in color as in lavish profusion, it blossoms everywhere - in woods, waysides, meadows, and marshes, but always in finer form in cool, shady dells; with longer flowering scapes in meadow bogs; and with longer leaves than wide in swampy woodlands.The heart-shaped, saw-edged leaves, folded toward the center when newly put forth, and the five-petalled, bluish-purple, golden-hearted blossom are too familiar for more detailed description.From the three-cornered stars of the elastic capsules, the seeds are scattered abroad.
Beards on the spurred lower petal and the two side petals give the bees a foothold when they turn head downward, as some must, to suck nectar.This attitude enables them to receive the pollen dusted on their abdomens, when they jar the flower, at a point nearest their pollen-collecting hairs.It is also an economical advantage to the flower which can sift the pollen downward on the bee instead of exposing it to the pollen-eating interlopers.
Among the latter may be classed the bumblebees and butterflies whose long lips and tongues pilfer ad libitum."For the proper visitors of the bearded violets," says Professor Robertson, "we must look to the small bees, among which the Osmias are the most important."When science was younger and hair splitting an uncommon indulgence of botanists, the EARLY BLUE VIOLET (Viola palmata)was thought to be simply a variety of the common purple violet, whose heart-shaped leaves frequently show a tendency to divide into lobes.But the early blue violet, however roundish or heart-shaped its early leaves may be, has the later ones variously divided into from three to thirteen lobes, often almost as much cut on the sides as the leaves of the bird's-foot violet.
In dry soil, chiefly in the woods, this violet may be found from Southern Canada westward to Minnesota, and south to northern boundaries of the Gulf States.Only its side petals are bearded to form footrests for the insects that search for the deeply secreted nectar.Many butterflies visit this flower.On entering it a bee must first touch the stigma before any fresh golden pollen is released from the anther cone, and cross-fertilization naturally results.
In shale and sandy soil, even in the gravel of hillsides, one finds the narrowly divided, finely cut leaves and the bicolored beardless blossom of the BIRD'S-FOOT VIOLET (V.pedata), pale bluish purple on the lower petals, dark purple on one or two upper ones, and with a heart of gold.The large, velvety, pansy-like blossom and the unusual foliage which rises in rather dense tufts are sufficient to distinguish the plant from its numerous kin.This species produces no cleistogamous or blind flowers.Frequently the bird's-foot violet blooms a second time, in autumn, a delightful eccentricity of this family.The spur of its lower petal is long and very slender, and, as might be expected, the longest-tongued bees and butterflies are its most frequent visitors.These receive the pollen on the base of the proboscis.
The WOOLLY BLUE VIOLET (V.sororia), whose stems and younger leaves, at least, are covered with hairs, and whose purplish-blue flowers are more or less bearded within, prefers a shady but dry situation; whereas its next of kin, the ARROW-LEAVED VIOLET (V.