in his "Synopsis of North American Birds," and in his report on the rapacious birds in Professor Baird's great work on the "Birds of North America." If not a valid species, of which there seems to be but slight evidence, it must be either an immature White-headed Eagle or an immature Northern Sea Eagle (Haliaëtus albicilla), since these are its only known near allies, though neither of these are known to ever quite equal it in size. The White-headed Eagle ranges in alar extent from a little less than seven feet to a little more than eight; and the Northern Sea Eagle is of about the same size. That it is not the latter is evident from the fact that Audubon describes his bird as breeding in Kentucky, a locality far south of the known range of the truly arctic Sea Eagle. It would be one of the strangest facts in natural history that a bird like Audubon's Washington Eagle should remain undiscovered for more than fifty years, when its alleged habitat is within the settled parts of the United States. On the whole it seems to me tolerably evident that this supposed species should be considered as based on a large example of H. leucocephalus, and that a "few grains of allowance" may be safely made for slight inaccuracies on the part of its enthusiastic discoverer. The bird referred to above by Mr. Jarvis I regard as unquestionably referable to the H. leucocephalus.† * Ibid. † Farther remarks concerning the "Washington Eagle" may be found in the writer's "Catalogue of the Winter Birds of Florida," etc., in the "Bulletin of the Museum of Comparative Zoology," now in press, as well as concerning Bartram's mythical "Sacred Vulture," based on a singular combination of certain characters of the Caracara Eagle (Polyborus tharus Cassin), the White-headed Eagle (Haliaëtus leucocephalus), and the John Crow (Sarcorhamphus papa) of the West Indies. Reasons are there given also for referring the Haliaëtus pelagicus to the H. albicilla. ACCLIMATIZATION OF FOREIGN TREES AND PLANTS.* BY ALFRED W. BENNETT. THE introduction of new forms of vegetable life into our gardens and greenhouses has made considerable progress during recent years. The Acclimatization Societies of Paris. and London have, it is true, paid more attention to the domestication of foreign animals than of plants; something, however, has been attempted in this direction, and with considerable success. This branch of acclimatization would, indeed, seem likely to be the most fertile in results beneficial to mankind. For one fresh animal introduced that will be of real utility, there will probably be a dozen plants that yield important economical products. The early races of mankind appear to have exhausted our powers over the lower animals-the horse, the ass, the dog, the camel, the ox, the sheep, were all brought under subjection to man at the earliest period of his history; and within historic times no important addition has been made to the number of our domestic animals. Not so with plants. A large number of the vegetable substances used as food at the present day, and of the vegetable articles of manufacture, were unknown to the ancients; and the field for farther extension of our utilization of the vegetable kingdom seems indefinitely large. The power of cultivation in modifying plants is also much greater than any corresponding power of domestication in modifying animals. The oldest extant drawings of the horse, the ox, or the camel, scarcely point out any distinctive features from their descendants now living; the potato and the apple, on the other hand, may almost be considered as man *This article is introduced since it contains many hints of use to florists and gardeners in the middle states especially, where many subtropical plants can with care be made to grow. - EDITORS. ufactured products; while many gardeners' flowers, such as the Pelargonium and the Tulip, differ so widely from their ancestors as, in some cases, to obscure their parentage. The term acclimatization has been objected to by some scientific men, on the ground that the descendants of any animal or plant which has been transported from one climate to another have no more power than their ancestor of adapting themselves to that climate, unless the principle of Natural Selection has come into play to eliminate the individuals least able to adapt themselves to the new climate, those only surviving which, from some cause or other, are most suited to the fresh conditions. Be this as it may, there is no question about the fact that the farmer and the gardener have it in their power to naturalize plants foreign to our climate and our soil. But the conditions of this naturalization are by no means so simple as might at first sight appear. It might naturally be supposed that all we have to do is to introduce those plants which grow spontaneously in a climate and a soil similar to our own, and that they will necessarily flourish, and will scarcely be aware of the change. Or, if they come from a warmer country that all that is needed is to protect. them by glass and artificial warmth from the inclemency of our winters. But in practice this is not found to be the case. A plant will frequently obstinately refuse to become naturalized in a country, the climatal and geological conditions of which are similar to those that occur in the region where it is indigenous. Our common daisy, a native of almost every country of Europe, is said to have resisted all attempts to introduce it even into the gardens of the United States. Some plants seem to have an unconquerable aversion to the fostering hand of man, even in their own country. A wellconstructed and carefully kept fernery will contain specimens, more or less luxuriant, of nearly all our native ferns; the polypody and hartstongue from shady banks and treestumps; the so-called male and female ferns from the woods; the spleenwort from dry walls; even the royal "floweringfern" from bogs; and some of the semi-alpine species will flourish with the exercise of a little care. One kind, however, is almost invariably absent, and that the most widely distributed of all our ferns, the common break, a native of every county and almost of every parish in the country, but which can seldom be induced to remain a denizen of soil that has once been brought under man's dominion. On the other hand some of the greatest favorites of our gardens, which display no coyness whatever in overrunning our flower-beds, are natives of countries where the climate presents very different features to our own, or of very limited tracts of our own country, to which they seem strictly confined by impassable barriers of soil or meteorological conditions. To take instances of the latter phenomenon :-There is no garden flower more cosmopolitan in its tastes, more certain to thrive under any conditions of light or heavy soil, sun or shade, care or neglect, even in the heart of a town, as its very name seems to indicate, than the London Pride. Yet the Saxifraga umbrosa is one of the most restricted in distribution of our native plants. Abundant enough where it does grow, it is yet entirely confined to the moist equable climate of the hilly country in the south-west of Ireland and a few other similar localities, beyond which it is never found in the wild state. Botanists will think themselves amply repaid for a toilsome day's march by gathering the beautiful Polemonium cæruleum in its native habitat among the calcareous hills of the west of Yorkshire; yet the Jacob's Ladder is an ornament of every garden on the very stiffest part of the London clay. Probably every piece of cultivated ground, which contains a laburnum tree, produces each spring a plentiful crop of self-sown young trees, which come up without the least care or protection until destroyed in the process of weeding; yet the laburnum shows no disposition to take a place among the naturalized trees of our woods and hedges, although the seeds must often be carried there by birds. It is remarkable that many of our common vegetables, the cabbage, the asparagus, the sea-kale, the celery, are natives of our own shores, never growing spontaneously out of reach of the salt spray; and yet requiring, when transplanted into our gardens, no peculiarity of soil or treatment to enable them to support a vigorous existence. These are instances of plants to which our climate appears entirely congenial, and yet which seem as if they could not propagate themselves with us or spread, except under man's protection. Others, again, appear to require only to get a footing in a foreign soil to become established in it with extraordinary rapidity, even to the overmastering or expulsion of some of the indigenous inhabitants. When Australia and New Zealand were first colonized by Europeans, their flora presented an aspect of perfect strangeness, very few of the native trees or flowers belonging even to genera common to Europe. The seeds of some of our English weeds were, however, introduced, intentionally or accidentally, by the early settlers; and now the thistle covers the waste lands of Australia as it does in England, and the clover and the groundsel every where remind the Englishman of his faraway home, and have become as completely at home as the mustangs or wild-horses on the pampas of South America. In our own country a very remarkable instance of this rapid naturalization has occurred in the case of the Elodea Canadensis or Canadian water-weed; which, introduced not many years since into our canals from Canada, has now become such a pest in many places as seriously to impede the navigation. Other instances might be mentioned of foreign plants introduced with seed having in a very short time become common weeds in all cultivated land. Indeed, many of the species included in our handbooks of British plants are so entirely confined to arable land or to spots in the immediate vicinity of human dwellings, that it is impossible to say how many of them may be really indigenous to the soil, and how many naturalized aliens. |