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.
Flower - An inflated, curved, yellowish-green, veiny tube (calyx), pipe-shaped, except that it abruptly broadens beyond the contracted throat into 3 flat, spreading, dark purplish or reddish-brown lobes; pipe 1 to 1 1/2 in. long, borne on a long, drooping peduncle, either solitary or 2 or 3 together, from the bracted leaf-axils; 6 anthers, without filaments, in united pairs under the 3 lobes of the short, thick stigma. Stem: A very long, twining vine, the branches smooth and green. Leaves: Thin, reniform to heart-shaped, slender petioled, downy underneath when young; 6 to 15 in. broad when mature.
Fruit - An oblong, cylindric capsule, containing quantities of seeds within its six sections.
Preferred Habitat - Rich, moist woods.
Flowering Season - May - June.
Distribution - Pennsylvania, westward to Minnesota, south to Georgia and Kansas. Escaped from cultivation further north.
After learning why the pitcher plant, Jack-in-the-pulpit, and skunk cabbage are colored and shaped as they are, no one will be surprised on opening this curious flower to find numbers of little flies within the pipe. Certain relatives of this vine produce flowers that are not only colored like livid, putrid meat around the entrance, but also emit a foetid odor to attract carrion flies especially. (See purple trillium, p. 7.)
In May, when the pipe-vine blooms, gauzy-winged small flies and gnats gladly seek food and shelter from the wind within so attractive an asylum as the curving tube offers. They enter easily enough through the harrow throat, around which fine hairs point downward - an entrance resembling an eel trap's. Any pollen they may bring in on their bodies now rubs off on the sticky stigma lobes, already matured at the bottom of a newly opened flower, in which they buzz, crawl, slide, and slip, seeking an avenue of escape. None presents itself: they are imprisoned! The hairs at the entrance, approached from within, form an impenetrable stockade. Must the poor little creatures perish? Is the flower heartless enough to murder its benefactors, on which the continuance of its species depends? By no means is it so shortsighted! A few tiny drops of nectar exuding from the centre table prevent the visitors from starving. Presently the fertilized stigmas wither, and when they have safely escaped the danger of self-fertilization, the pollen hidden under their lobes ripens and dusts afresh the little flies so impatiently awaiting the feast. Now, and not till now, it is to the advantage of the species that the prisoners be released, that they may carry the vitalizing dust to stigmas waiting for it in younger flowers. Accordingly, the slippery pipe begins to shrivel, thus offering a foothold; the once stiff hairs that guarded its exit grow limp, and the happy gnats, after a generous entertainment and snug protection, escape uninjured, and by no means unwilling to repeat the experience. Evidently the wild ginger, belonging to a genus next of kin, is striving to perfect a similar prison. In the language of the street, the ginger flower does not yet "work" its visitors "for all they are worth."
Later, when we see the exquisite dark, velvety, blue-green, pipe-vine swallow-tail butterfly (Papilio philenor) hovering about verandas or woodland bowers that are shaded with the pipe-vine's large leaves, we may know she is there only to lay eggs that her caterpillar descendants may find themselves on their favorite food store.
The Virginia Snakeroot, or Serpentary (A. Serpentaria), found in dry woods, chiefly in the Middle States and South, although its range extends northward to Connecticut, New York, and Michigan, is the species whose aromatic root is used in medicine. It is a low-growing herb, not a vine; its heart-shaped leaves, which are narrow and tapering to a point, are green on both sides, and the curious, greenish, S-shaped flower, which grows alone at the tip of a scaly footstalk from the root, appears in June or July. Sometimes the flowers are cleistogamous (see p. 108).