existing species. These, and their fellows, or such as survive, must have been pushed on to lower latitudes as the cold advanced, just as they now would be if the temperature were to be again lowered; and between them and the ice there was doubtless a band of subarctic and arctic vegetation—portions of which, retreating up the mountains as the climate ameliorated and the ice receded, still scantily survive upon our highest Alleghanies, and more abundantly upon the colder summits of the mountains of New York and New England-demonstrating the existence of the present arctic alpine vegetation during the glacial era; and that the change of climate at its close was so gradual that it was not destructive to vegetable species. As the temperature rose, and the ice gradually retreated, the surviving temperate flora must have returned northward pari passu, and—which is an important point-must have advanced much farther northward, and especially northwestward, than it now does; so far, indeed, that the temperate floras of North America and of Eastern Asia, after having been for long ages most widely separated, must have become a second time conterminous. Whatever doubts may be entertained respecting the existence of our present vegetation generally before the glacial era, its existence immediately after that period will hardly be questioned. Here, therefore, may be adduced the direct evidence recently brought to light by Mr Lesquereux, who has identified our live oak (Quercus virens), Pecan (Carya olivaformis), Chinquapin (Castana pumila), Planer-tree (Planera Gmelina), Honey-Locust (Gleditschia triacanthos), Prinos coriaceus, and Acorus Calamus,-besides an elm and a Ceanothus doubtfully referable to existing species-on the Mississippi, near Columbus, Kentucky, in beds which Mr Lesquereux regards as anterior to the drift. Professor D. D. Owen has indicated their position "as about 120 feet lower than the ferruginous sand in which the bones of the Megalonyx Jeffersonii were found." So that they belong to the period immediately succeeding the drift, if not to that immediately preceding it. All the vegetable remains of this deposit, which have been obtained in a determinable condition, have been referred, either positively or probably, to existing species of the United States flora, most of them now inhabiting the region a few degrees farther south. If, then, our present temperate flora existed at the close of the glacial epoch, the evidence that it soon attained a high northern range is ready to our hand. For then followed the second epoch of the post-tertiary, called the fluvial by Dana, when the region of St Lawrence and Lake Champlain was submerged, and the sea there stood five hundred feet above its present level; when the higher temperate latitudes of North America, and probably the arctic generally, were less elevated than now, and the rivers vastly larger, as shown by the immense upper alluvial plains, from fifty to three hundred feet above their present beds; and when the diminished breadth and lessened height of northern land must have given a much milder climate than the present.-Silliman's American Journal, September 1859. By Remarks on the Botany of Japan, in its Relations to that of North America, and of other parts of the Northern Temperate Zone. Professor ASA GRAY.-It is interesting to notice that, notwithstanding the comparative proximity of Japan to Western North America, fewer of its species are represented there than in far distant Europe. Alsoshowing that this difference is not owing to the separation by an ocean -that far more Japanese plants are represented in Eastern North America than in either. It is, indeed, possible that my much better knowledge of American botany than of European may have somewhat exaggerated this result in favour of Atlantic North America as against Europe, but it could not as against Western North America. If we regard the identical species only, in the several floras, the preponderance is equally against Western as compared with Eastern North America, but is more in favour of Europe. For the number of species in the Japanese column which likewise occur in Western North America is about 120; in Eastern North America, 134; in Europe, 157. Of the 580 Japanese entries, there are which have corresponding European representatives, a little above 8.48 per cent. of identical species, 0.27 Western N. American representatives, about 0.37 Eastern 39 0.61 0.20 0.23 So geographical continuity favours the extension of identical species; but still Eastern North America has more in common with Japan than Western North America has. The relations of this kind between the floras of Japan and of Europe are obvious enough; and the identical species are mostly such as extend continuously as they readily may-throughout Russian Asia, some few only to the eastern confines of Europe, but most of them to its western borders. To exhibit more distinctly the features of identity between the floras of Japan and of North America, and also the manner in which these are distributed between the eastern and the western portions of our continent-after excluding those species which range around the world in the northern hemisphere, or the greater part of it, or (which is nearly the same thing in the present view) which are unknown in Europe -I will enumerate the remaining peculiar species which Japan possesses in common with America : In Japan. Vaccinium macrocarpon Trillium erectum, var. Juncus xiphioides Adiantum pedatum A. pedatum A. pedatum The names enclosed in parentheses are of species which I have not seen from Japan; some of them inhabit the adjacent mainland ; some are imperfectly identified. Those marked * are high northern species in America. Of those 56 extra-European species, 35 inhabit Western, and 41 Eastern North America. And 15 are Western, and not Eastern; 21 Eastern and not Western; and 20 common to both sides of the continent. Eight or ten of these 56 species extend eastward into the interior of Asia. On the other hand, the only species which I can mention as truly indigenous both to Japan and to Europe, but not recorded as ranging through Asia, are Euonymus latifolius, Fagus sylvatica, NEW SERIES.-VOL. XI. NO. I.—JAN. 1860. Blechnum Spicant, T Valeriana dioica, Streptopus amplexifolius, Athyrium fontanum, Two of these species extend across the northern part of the American continent, and on to the Asiatic; another occurs on the north-west coast of America; and another, the Fagus, is represented in Eastern America by a too closely related species. It is noteworthy, that not one of these seven plants is of a peculiarly European genus, or even a Europao-Siberian genus; while of the fifty-six species of the Americo-Japanese region wanting in Europe, twenty are of extra-European genera; seventeen are of genera restricted to the North American, East Asian, and Himalayan regions (except that Brasenia has wandered to Australia); fourteen of the genera (most of them monotypic) are peculiar to America and Japan, or the districts immediately adjacent; one is peculiar to our north-west coast and Japan; and eight are monotypic genera wholly peculiar (Brasenia excepted) to the Atlantic United States and Japan. Add to these the similar cases of other American species (nearly all of them peculiarly Atlantic-American) which have been detected in the Himalayas or in Northern Asia,—such as Menispermum Canadense (Dauricum, DC.), Amphicarpaa monoica? Clitoria Mariana, Osmorrhiza brevistylis, Monotropa uniflora, Phryma leptostachya, Tipularia discolor? &c.—and it will be almost impossible to avoid the conclusion, that there has been a peculiar intermingling of the Eastern American and Eastern Asian floras, which demands explanation. The case might be made yet stronger by reckoning some subgeneric types as equivalent to generic in the present view, and by distinguishing those species or genera which barely enter the eastern borders of Europe; e.g., Cimicifuga fætida, Mahringia lateriflora, Geum strctum, Spiræia salicifolia, &c. It will be yet more strengthened, and the obvious conclusion will become irresistible, when we take the nearly allied, as well as the identical, species into account. And also when we consider that, after excluding the identical species, only 15 per cent. of the entries in the European column of the detailed tabular view are in italic type (i.e., are closely representative of Japanese species); while there are 22 per cent. of this character in the American column. For the latter, I need only advert to some instances of such close representation, as of Trollius patulus by T. Americanus, Aquilegia Burgeriana Rhus verniciflua and many others of the same sort,-several of which, when better known, may yet prove to be conspecific; while an equally large number could be indicated of species which, although more positively different, are yet no less striking counterparts. To demonstrate the former proposition, I have only to contrast the extra-American genera common to Europe and Japan with the extraEuropean genera common to North America and Japan. The principal European genera of this category are-Adonis, Epimedium, Chelidonium, Malachium, Lotus, Anthriscus, Hedera, Asperula, Rubia, Carpesium, Ligularia, Lapsana, Picris, Pæderota, Ajuga, Thymus, Nepeta, Lamium, Ligustrum, Kochia? Daphne, Thesium, Buxus, Mercurialis, Cephalanthera, Paris, Asparagus-to which may as well be added Paonia and Bupleurum, the former having a representative on the mountains, and the latter in the arctic regions, of Western America, but both absent from the rest of our continent. Excepting Pæderota and Buxus (the latter a rather doubtful native of Eastern Asia), none of these genera are peculiar to Europe, but all extend throughout Asia and elsewhere over large parts of the world.-American Journal, September 1859. Vegetable Hybrids.—In August 1858 M. Naudin fecundated the flowers of Datura lævis with the pollen of Datura Stramonium. He collected the seeds in October 1858, and sowed them in April 1859. The habit and general aspect of the plants which grew from these seeds resembled those of D. Stramonium. The flowers appeared later than those of the parents. The capsules for the most part were similar to those of D. Stramonium. In some, however, on the contrary, the characters of D. lavis were so decided that it was difficult to distinguish the capsules from those of that species. Again, in some of the fruits intermediate characters were seen, the fourth, third, half, or threequarters of the same fruit belonging exclusively to one or other of the parent species. Thus some of the capsules presented on one side a deep green surface, covered with sharp points, like those of D. Stramonium, whilst the other side exhibited the grayish tint and the smooth surface of the capsules of D. lavis. The influence, however, of D. Stramonium seemed to prevail most.-L'Institut, 9th Nov. 1859. Vegetation of the Sea of Aral.-In 1857, the Imperial Academy of Sciences of St Petersburgh projected a zoological and botanical expedition to explore the steppes around the Sea of Aral, and placed it under the charge of two young naturalists, MM. Sévertzoff and Bortscheff. The first gentleman was killed in an encounter with the native tribes; but the expedition was continued by M. Bortscheff, and one of its more important results was the discovery, upon the north-east shore of the Sea of Aral, of a marine vegetation, exhibiting numerous species and entire families of plants (alga), belonging exclusively to that which abounds in a deep sea, and which has never been met with in the salt or fresh water lakes situate in the interior. This discovery presents to botanists points of great geographical and historical interest, confirming the fact, in a manner not to be disputed, that the Sea of Aral is not a lake, but the bed of an ancient sea. It was previously known that its mollusca, if not identical, presented at least a great resemblance to those of the open seas; but botanists were until now ignorant of the existence of a marine |