Wild Flowers Worth Knowing Part 16

_Distribution_--Nova Scotia and Manitoba, southward to North Carolina.

Also a native of Europe.

Clumps of these delicate little pinkish blossoms and abundant leaves, cuddled close to the cold earth of northern forests, usually conceal near the dry leaves or moss from which they spring blind flowers that never open--cleistogamous the botanists call them--flowers that lack petals, as if they were immature buds; that lack odor, nectar, and entrance; yet they are perfectly mature, self-fertilized, and abundantly fruitful. Fifty-five genera of plants contain one or more species on which these peculiar products are found, the pea family having more than any other, although violets offer perhaps the most familiar instance to most of us. Many of these species bury their offspring below ground; but the wood-sorrel bears its blind flowers nodding from the top of a curved scape at the base of the plant, where we can readily find them.

By having no petals, and other features a.s.sumed by an ordinary flower to attract insects, and chiefly in saving pollen, they produce seed with literally the closest economy. It is estimated that the average blind flower of the wood-sorrel does its work with four hundred pollen grains, while the prodigal peony scatters with the help of wind and insect visitors more than three and a half millions!

As self-fertilization is impossible, the showy blossoms of the wood-sorrel are a necessity not a luxury; for the insects must not be allowed to overlook them.

Every child knows how the wood-sorrel "goes to sleep" by drooping its three leaflets until they touch back to back at evening, regaining the horizontal at sunrise--a performance most scientists now agree protects the peculiarly sensitive leaf from cold by radiation. During the day as well, seedling, scape, and leaves go through some interesting movements, closely followed by Darwin in his "Power of Movement in Plants," which should be read by all interested.

_Oxalis_, the Greek for sour, applies to all sorrels because of their acid juice; but _acetosella_ = vinegar salt, the specific name of this plant, indicates that from it druggists obtain salt of lemons. Twenty pounds of leaves yield between two and three ounces of oxalic acid by crystallization. Names locally given the plant in the Old World are wood sour or sower, cuckoo's meat, sour trefoil, and shamrock--for this is St. Patrick's own flower, the true shamrock of the ancient Irish, some claim. Alleluia, another folk-name, refers to the joyousness of the Easter season, when the plant comes into bloom in England.

Violet Wood-sorrel

_Oxalis violacea_

_Flowers_--Pinkish purple, lavender, or pale magenta; less than 1 in.

long; borne on slender stems in umbels or forking cl.u.s.ters, each containing from 3 to 12 flowers. Calyx of 5 obtuse sepals; 5 petals; 10 (5 longer, 5 shorter) stamens; 5 styles persistent above 5-celled ovary.

_Stem:_ From brownish, scaly bulb 4 to 9 in. high. _Leaves:_ About 1 in.

wide, compounded of 3 rounded, clover-like leaflets with prominent midrib borne at end of slender petioles, springing from root.

_Preferred Habitat_--Rocky and sandy woods.

_Flowering Season_--May-June.

_Distribution_--Northern United States to Rocky Mountains, south to Florida and New Mexico; more abundant southward.

Beauty of leaf and blossom is not the only attraction possessed by this charming little plant. As a family the wood-sorrels have great interest for botanists since Darwin devoted such exhaustive study to their power of movement, and many other scientists have described the several forms a.s.sumed by perfect flowers of the same species to secure cross-fertilization. Some members of the clan also bear blind flowers, which have been described in the account of the white wood-sorrel. Even the rudimentary leaves of the seedlings "go to sleep" at evening, and during the day are in constant movement up and down. The stems, too, are restless; and as for the mature leaves, every child knows how they droop their three leaflets back to back against the stem at evening, elevating them to the perfect horizontal again by day. Extreme sensitiveness to light has been thought to be the true explanation of so much activity, and yet this is not a satisfactory theory in many cases.

It is certain that drooping leaves suffer far less from frost than those whose upper surfaces are flatly exposed to the zenith. This view that the sleep of leaves saves them from being chilled at night by radiation is Darwin's own, supported by innumerable experiments; and probably it would have been advanced by Linnaeus, too, since so many of his observations in "Somnus Plantarum" verify the theory, had the principle of radiation been discovered in his day.

GERANIUM FAMILY _(Geraniaceae)_

Wild or Spotted Geranium or Crane's-Bill; Alum-root

_Geranium maculatum_

_Flowers_--Pale magenta, purplish pink, or lavender, regular, 1 to 1-1/2 in. broad, solitary or a pair, borne on elongated peduncles, generally with pair of leaves at their base. Calyx of 5 lapping, pointed sepals; 5 petals, woolly at base; 10 stamens; 1 pistil with 5 styles. _Fruit:_ A slender capsule pointed like a crane's bill. In maturity it ejects seeds elastically far from the parent plant. _Stem:_ 1 to 2 ft. high, hairy, slender, simple or branching above. _Leaves:_ Older ones sometimes spotted with white; basal ones 3 to 6 in. wide, 3 to 5 parted, variously cleft and toothed; 2 stem leaves opposite.

_Preferred Habitat_--Open woods, thickets, and shady roadsides.

_Flowering Season_--April-July.

_Distribution_--Newfoundland to Georgia, and westward a thousand miles.

Sprengel, who was the first to exalt flowers above the level of mere botanical specimens, had his attention led to the intimate relations.h.i.+p existing between plants and insects by studying out the meaning of the hairy corolla of the common Wild Geranium of Germany _(G. sylvatic.u.m)_, being convinced, as he wrote in 1787, that "the wise Author of Nature has not made even a single hair without a definite design." A hundred years before, Nehemias Grew had said that it was necessary for pollen to reach the stigma of a flower in order that it might set fertile seed; and Linnaeus had to come to his aid with conclusive evidence to convince a doubting world that this was true. Sprengel made the next step forward, but his writings lay neglected over seventy years because he advanced the then incredible and only partially true statement that a flower is fertilized by insects which carry its pollen from its anthers to its stigma. In spite of his discoveries that the hairs inside the geranium's corolla protect its nectar from rain for the insect's benefit, just as eyebrows keep perspiration from falling into the eye; that most flowers which secrete nectar have what he termed "honey guides"--spots of bright color, heavy veining, or some such pathfinder on the petals--in spite of the most patient and scientific research that shed great light on natural selection a half-century before Darwin advanced the theory, he left it for the author of "The Origin of Species" to show that cross-fertilization--the transfer of pollen from one blossom to another, not from anthers to stigma of the same flower--is the great end to which so much marvellous mechanism is chiefly adapted. Cross-fertilized blossoms defeat self-fertilized flowers in the struggle for existence.

No wonder Sprengel's theory was disproved by his scornful contemporaries in the very case of his Wild Geranium, which sheds its pollen before it has developed a stigma to receive any; therefore no insect that had not brought pollen from an earlier bloom could possibly fertilize this flower. How amazing that he did not see this! Our common wild crane's-bill, which also has lost the power to fertilize itself, not only ripens first the outer, then the inner, row of anthers, but actually drops them off after their pollen has been removed, to overcome the barest chance of self-fertilization as the stigmas become receptive.

This is the geranium's and many other flowers' method to compel cross-fertilization by insects. In cold, stormy, cloudy weather a geranium blossom may remain in the male stage several days before becoming female; while on a warm, sunny day, when plenty of insects are flying, the change sometimes takes place in a few hours. Among others, the common sulphur or puddle b.u.t.terfly, that sits in swarms on muddy roads and makes the clover fields gay with its bright little wings, pilfers nectar from the geranium without bringing its long tongue in contact with the pollen. Neither do the smaller bees and flies which alight on the petals necessarily come in contact with the anthers and stigmas. Doubtless the larger bees are the flowers' true benefactors.

The so-called geraniums in cultivation are pelargoniums, strictly speaking.

Herb Robert; Red Robin; Red Shanks; Dragon's Blood

_Geranium Robertianum_

_Flowers_--Purplish rose, about 1/2 in. across, borne chiefly in pairs on slender peduncles. Five sepals and petals; stamens 10; pistil with 5 styles. _Stem_: Weak, slender, much branched, forked, and spreading, slightly hairy, 6 to 18 in. high. _Leaves_: Strongly scented, opposite, thin, of 3 divisions, much subdivided and cleft. _Fruit_: Capsular, elastic, the beak 1 in. long, awn-pointed.

_Preferred Habitat_--Rocky, moist woods and shady roadsides.

_Flowering Season_--May-October.

_Distribution_--Nova Scotia to Pennsylvania, and westward to Missouri.

Who was the Robert for whom this his "holy herb" was named? Many suppose that he was St. Robert, a Benedictine monk, to whom the twenty-ninth of April--the day the plant comes into flower in Europe--is dedicated.

Others a.s.sert that Robert Duke of Normandy, for whom the "Ortus Sanitatis," a standard medical guide for some hundred of years, was written, is the man honored; and since there is now no way of deciding the mooted question, we may take our choice.

Only when the stems are young are they green; later the plant well earns the name of Red Shanks, and when its leaves show crimson stains, of Dragon's Blood.

At any time the herb gives forth a disagreeable odor, but especially when its leaves and stem have been crushed until they emit a resinous secretion once an alleged cure for the plague.

MILKWORT FAMILY _(Polygalaceae)_

Fringed Milkwort or Polygala; Flowering Wintergreen; Gay Wings

_Polygala paucifolia_

_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_: Cl.u.s.tered 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 b.u.t.terflies that have settled among the wintergreen leaves. Unlike the common milkwort and many of its kin that grow in clover-like 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.

Common, Field, or Purple Milkwort; Purple Polygala

_Polygala sanguinea (P. viridescens)_