THE

AMERICAN NATURALIST.

Vol. IV. - DECEMBER, 1870.- No. 10.

со

THE FLORA OF THE PRAIRIES.

BY J. A. ALLEN.

PROBABLY the vegetation of no two adjoining regions, both of which are situated between the same parallels of latitude and at nearly the same height above the sea, presents greater differences than exist between the vegetation of the fertile prairies of the Mississippi Valley and the forest region that extends from their eastern border to the Atlantic coast. To one who has always lived amid the diversified scenery of the Eastern or Middle States, where distant mountains almost everywhere bound the view, and forestcrowned hills and cultivated valleys so agreeably alternate as to dispel the possibility of monotony, a first view of the primitive prairies,

"The unshorn fields, boundless and beautiful,"

as Bryant has so felicitously described them, which

"stretch

In airy undulations far away

As if the ocean, in his gentlest swell,

Stood still, with all his rounded billows fixed

And motionless forever,"

is extremely novel and full of interest. But the prairies, "unshorn" of their primitive wildness will soon be things of the past, so great are the attractions they hold forth to the emigrant, and so rapid the transformation that follows their

Entered according to Act of Congress, in the year 1870, by the PEABODY ACADEMY OF SCIENCR, in the Clerk's Office of the District Court of the District of Massachusetts.

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settlement. Already there are few localities east of the Missouri where their primal simplicity and beauty have not already been more or less modified.

Great changes in the vegetation of a new country necessarily result from its settlement by an agricultural people, but the rapidity and ultimate completeness of the transformation greatly depend upon the relative susceptibility of the country to cultivation. Since vast areas of the prairies offer no obstructions to the revolutionizing plow, the astonishing rapidity of the change in the flora that follows its march can scarcely be conceived by those who have not witnessed its actual progress. No sooner is the sod inverted than scores of species of the original and most characteristic plants almost wholly disappear; in a few years the luxuriant wild grasses, overtopped with showy flowers, varying the hue of the landscape with the advancing season, have become supplanted by the cultivated grasses and the cereals, and that constant scourge of the agriculturist, the ever intrusive weeds. The timber no longer remains confined to narrow belts skirting the streams, for besides the newly-set orchards, rapidly growing kinds of trees, planted to afford shelter from the fierceness of the summer's sun and the fury of the bleak winter winds, everywhere diversify the landscape, while comfortable log cabins, or neatly painted, commodious houses give an air of civilization to districts that at no distant period were the undisturbed home of the buffalo and the elk.

Far more slow has been the change at the eastward, where the forests have slowly yielded to the axe of the woodman, and where much of the land is too uneven for cultivation. Here the forests, though in the longest settled districts perhaps once or twice removed, still cover no inconsiderable part of the country, and consist, for the most part, of the indigenous trees in nearly their original proportions, while the lesser shrubs and the herbaceous plants they primitively sheltered are still persistent, and to a great de

gree occupy the neglected pastures, the roadsides and the waste nooks of the farms. In short the transformations of the flora of the prairies are often far more complete after a period of settlement covering but two decades, than are to be seen in those portions of New England which have been occupied by Europeans for as many centuries.

In the present article it is proposed to sketch briefly some of the peculiarities of the primitive flora of the Upper Mississippi prairies,* which not improperly, either in respect to their fertility under cultivation, or the luxuriance and beauty of their native vegetation, have been styled the "Garden of the West." The wild plants of the prairies present at every season features peculiarly attractive. In spring anemones and violets, as elsewhere, are among the early flowers, the latter of which are particularly numerous and characteristic, peering brightly out among the young fresh blades of grass. To these soon succeed several species of beautiful phloxes, the painted cup, and the prairie rose. Later still appear the purple and the white turban flowers (Petalostemon violaceus Michx., and P. candidus Michx.), the ceanothus, the hoary-leaved, purple-flowered lead plant (Amorpha canescens Nutt.), the purple cone flower (Echinacea angustifolia DC.), and, from its abundance perhaps the most conspicuous of all, the beautiful Coreopsis palmata, which here and there gives its own bright color to large patches of the undulating landscape. Blazing stars of several species (Liatris squarrosa Willd., L. pycnostachyà Michx., L. scariosa Willd.), with their long nodding spikes of rose-purple flowers soon follow, ranking among the most showy of the many showy plants. To these are soon added sunflowers of various species, most common of which are the Helianthus rigidus Desf., the H. giganteus Linn., the H. grosse-serratus Mart., the Actinomeris helianthoides Nutt., and the Lepachys pinnata T. & G.; the tall compass plant (Silphium lacini

The region more especially under consideration is Northern Illinois, and Central and Western Iowa.

atum Linn.); the Indian plantain (Cacalia tuberosa Nutt.), the tall verbena (V. hastata Linn.), and the yucca-leaved rattlesnake master (Eryngium yuccafolium Michx.); all generally remarkable either for their large showy flowers, or the peculiar character of their foliage or habits. Finally the season closes with the later sunflowers and coreopses, some of which are of gigantic size, towering far above one's head; the purple-flowered gaurias and the golden epilobiums. From the first springing up of the early flowers till the frosts of autumn end the floral season, the prairies are arrayed in bright and showy hues by a succession of species of larger and taller growth, each later set not only overtopping their predecessors, but the rapidly growing prairie grasses. Ever varied too are the prevailing colors. Here blue prevails, there white or purple, and again large tracks are golden, as everywhere a few prevailing forms give character to the vegetation. Generally they are coarse, large plants, often resinous, with thick, harsh leaves and large flowers, and nearly all are species never or rarely met with in the Atlantic States, and never as characteristic species of the eastern flora. The Composite and the Leguminosa are preeminently the prevailing families, far more so indeed than at the eastward.

Many of the species are in various ways remarkable, but none more so perhaps than the plant popularly known as the compass plant (Silphium laciniatum), whose large, thick, rigid, upright root-leaves, one to two and a half feet long, are reputed to uniformly present their edges north and south, whence its name. Though they do not thus invariably arrange themselves, they generally stand in this direction, so uniformly in fact that they well serve as a convenient guide to the traveller in determining the points of the compass. Another species of the same genus, called the cup

*

*Since the above was written an interesting paper on the Compass Plant was read by Dr. Thomas Hill at the Troy meeting of the American Association for the Advance ment of Science, an abstract of which has just appeared in the NATURALIST (Vol. iv, p. 495, October, 1870). Dr. Hill refers this polarity to the sunlight, the two sides of the leaf being equally sensitive, and struggling for equal shares.

plant (S. perfoliatum), from the large opposite leaves of the stem being connate at their bases, forming a considerable cup-like cavity, capable of containing water, is common in the moist ravines. Other remarkable forms are the Indian plantain (Cacalia tuberosa), conspicuous for its thick, smooth, plantain-like leaves, deep-green on both sides and strongly ribbed; and the yucca-leaved rattlesnake master, or button snakeroot (Eryngium yuccafolium), with its linear grass-like, bristly fringed leaves, and its bracted flowers, closely sessile in dense heads,-an umbelliferous plant, but wholly unlike the generality of the species of the Umbellifera, both in its foliage and in the form of its inflorescence. The prairie clovers, or turban flowers (Pentalostemon), are among the most interesting of the leguminose species, and among the most characteristic. Their oblong or cylindrical heads of white or purple flowers are evidently suggestive of the latter name. Each head continues in flower for many days. At first the flowers form a band at the base of the head, which, gradually moving upward, later occupies the middle of the head, and finally its summit, recalling the Oriental head-dress, in allusion to which these plants have received one of their common names.

The habits of some of the sunflowers, but especially those of the Helianthus rigidus, present one feature of interest. The H. rigidus is one of the earliest flowering species and one of the most abundant ones, it being in some localities one of the most conspicuous and characteristic plants. By the middle of August it has attained nearly its full height, which commonly ranges from two and a half to four feet; the terminal heads of the earlier specimens have already begun to unfold their yellow rays, and those of the rest are nodding on their flexible stalks. It is a popular belief that the sunflower always turns its flowers towards the sun, but in reality so numerous are the exceptions to this rule in our garden sunflowers and in our common wild species of the East, that few observing people regard it doubtless as other