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 - Bright blue or violet blue, bell-shaped, 1/2 in. long or over, drooping from hair-like stalks. Calyx of 5-pointed, narrow, spreading lobes; 5 slender stamens alternate with lobes of corolla, and borne on summit of calyx tube, which is adherent to ovary; 1 pistil with 3 stigmas in maturity only. Stem: Very slender, 6 in. to 3 ft. high, often several from same root; simple or branching. Leaves: Lower ones nearly round, usually withered and gone by flowering season; stem leaves narrow, pointed, seated on stem. Fruit: An egg-shaped, pendent, 3-celled capsule with short openings near base; seeds very numerous, tiny.
Preferred Habitat - Moist rocks, uplands.
Flowering Season - June - September.
Distribution - Arctic regions of Europe, Asia, and America; southward on this continent, through Canada to New Jersey and Pennsylvania; westward to Nebraska, to Arizona in the Rockies, and to California in the Sierra Nevadas.
The inaccessible crevice of a precipice, moist rocks sprayed with the dashing waters of a lake or some tumbling mountain stream, wind-swept upland meadows, and shady places by the roadside may hold bright bunches of these hardy bells, swaying with exquisite grace on tremulous, hair-like stems that are fitted to withstand the fiercest mountain blasts, however frail they appear.
Harebell (Campanula rotundifolia)
How dainty, slender, tempting these little flowers are! One gladly risks a watery grave or broken bones to bring down a bunch from its aerial cranny.
It was a long stride forward in the evolutionary scale when the harebell welded its five once separate petals together; first at the base, then farther and farther up the sides, until a solid bell-shaped structure resulted. This arrangement which makes insect fertilization a more certain process because none of the pollen is lost through apertures, and because the visitor must enter the flower only at the vital point where the stigmas come in contact with his pollen-laden body, has given to all the flowers that have attained to it, marked ascendency.
Like most inverted blossoms, the harebell hangs its head to protect its nectar and pollen, not only from rain, but from the intrusion of undesirable crawling insects which would simply brush off its pollen in the grass before reaching the pistil of another flower, and so defeat cross-fertilization, the end and aim of so many blossoms. Advertising for winged insects by its bright color, the harebell attracts bees, butterflies, and many others. These visitors cannot well walk on the upright petals, and sooner or later must clasp the pistil if they would secure the nectar secreted at the base. In doing so, they will dust themselves and the immature pistil with the pollen from the surrounding anthers; but a newly opened flower is incapable of fertilization. The pollen, although partially discharged in the unopened bud, is prevented from falling out by a coat of hairs on the upper part of the style. By the time all the pollen has been removed by visitors, however, and the stamens which matured early have withered, the pistil has grown longer, until it looks like the clapper in a bell; the stigma at its top has separated into three horizontal lobes which, being sticky on the under side, a pollen-laden insect on entering the bell must certainly brush against them and render them fertile. But humblebees, its chief benefactors, and others may not have done their duty by the flower; what then? Why, the stigmas in that case finally bend backward to reach the left-over pollen, and fertilize themselves, obviously the next best thing for them to do. How one's reverence increases when one begins to understand, be it ever so little of, the divine plan!
"Probably the most striking blue and purple wild flowers we have," says John Burroughs, "are of European origin. These colors, except with the fall asters and gentians, seem rather unstable in our flora." This theory is certainly borne out in the case of the Rampion, European, or Creeping Bellflower (C. rapun-culoides), now detected in the act of escaping from gardens from New Brunswick to Ontario, Southern New York, Pennsylvania, and Ohio, and making itself very much at home in our fields and along the waysides. Compared with the delicate little harebell, it is a plant of rank, rigid habit. Its erect, rather stout stem, set with elongated oval, hairy, alternate leaves, and crowned with a onesided raceme of widely expanded, purple-blue bells rising about two feet above the ground, has little of the exquisite grace of its cousin. It blooms from July to September. This is the species whose roots are eaten by the omnivorous European peasant.
One of the few native campanulas, the Tall Bellflower (C Americana), waves long, slender wands studded with blue or sometimes whitish flowers high above the ground of moist thickets and woods throughout the eastern half of this country, but rarely near the sea. Doubtless the salt air, which intensifies the color of so many flowers, would brighten its rather slatey blue. The corolla, which is flat, round, about an inch across, and deeply cleft into five pointed petals, has the effect of a miniature pinwheel in motion. Mature flowers have the style elongated, bent downward, then curved upward, that the stigmas may certainly be in the way of the visiting insect pollen-laden from an earlier bloomer, and be cross-fertilized. The larger bees, its benefactors, which visit it for nectar, touch only the upper side of the style, on which they must alight; but the anthers waste pollen by shedding it on all sides. No insect can take shelter from rain or pass the night in this flower, as he frequently does in its more hospitable relative, the harebell. English gardeners, more appreciative than our own of our native flora, frequently utilize this charming plant in their rockwork, increasing their stock by a division of the dense, leafy rosettes.