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THE LOCAL DISTRIBUTION OF PLANTS.
677

have sought to solve the problem how this remarkable adaptation has been brought about, instead of pausing to question the alleged law of adaptation itself. And yet there have never been wanting numerous and obvious facts, especially in the vegetable kingdom, which, if interpreted at all, must be conceded to be incompatible with such a law, at least unless materially modified and greatly enlarged.

Mr. Thomas Meehan has remarked the fact that "almost all of our swamp-trees grow much better when they are transferred to drier places, provided the land is of fair quality. He referred, among others, to sweet-bay, red maple, weeping-willow, etc., as within his own repeated observations growing better out of swamps than in them." He further observes that "plants as a general rule, even those known as water-plants, prefer to grow out of water, except those that grow almost entirely beneath the surface."[1]

A great many facts are at hand to prove that those plants which are found habitually growing in wet ground may be easily made to grow in dry ground. The Iris versicolor (blue flag), which, in a state of Nature, grows universally in marshes, and keeps perpetual company with Nuphar (pond-lily) and Sagittaria (arrow-head), is a common occupant of the driest gardens. The Lobelia cardinalis (cardinal flower), which I have found below tide-water mark, is also a common garden-flower, and not difficult to cultivate. Almost as much may be said for Lobelia syphilitica (great lobelia). The calla, the caladiums, and the anthuriums, belong to this class, and the list might be indefinitely extended.

But differences of moisture in the soil are not the only ones which are often overcome by natural or artificial changes in the conditions of growth. Most of our prettiest wild-flowers which are found growing in deep, shaded glens in pure leaf-mould, have been captured by florists, and made to thrive as well, and often better, under a cultivation which, with their most faithful efforts to imitate it, must be a complete alteration of their native condition of life. Of such might be mentioned at random the Trillium (wake-robin), the Cypripedium (lady's-slipper), the Dicentra (Dutchman's breeches), the Uvularia (bell wort), the Erythronium (dog's-tooth violet), etc.

So, too, plants growing under other conditions, as on hillsides, and in open woods or meadows, as the violets, hepaticas, anemones, and others, offer no difficulty to the florist.

These are cases in which the transfer is from apparently more favorable conditions to those less favorable. But similar results follow from a reversal of this order. Plants may be successfully transferred to ordinary garden-soil from localities which we would naturally suppose to be less favorable to growth, but to which these seem to be specially adapted. The columbine (Aguilegia), which grows on rocks, often with scarcely any soil in which to root, or emerges from narrow

  1. See Popular Science Monthly for May, 1874, p. 126.