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Torrey and Gray are silent as to its presence on the Pacific, although from Hooker's work we might conclude that it existed there. The E. asperum, a closely allied species, flourishes in the plains eastward and westward of the mountain ranges, attaining the latitude of 65° on the McKenzie. Strictly speaking, the interior of the continent is its peculiar ground, as it does not in any quarter appear to approach the sea-coast within a considerable number of degrees. Nuttall has five others of this genus, none of which have yet been noted as on British territory. One is from Arkansas and Texas, two are from the elevated plains of the Rocky Mountains, one from the banks of the Willamet, and the fifth from the neighbourhood of Monterey, Upper California.

The second great division of Crucifera is like that of the SILIQUOS.E, very extensively distributed over all the temperate climes of the northern hemisphere, and British America has its portion of them. In the genus Vesicaria, the V. arctica extends from the island of Anticosti to the Arctic Regions, where it prevails most. The borders of the eastern prairies are probably the limit of its range westward, in the lat. of 52°. The V. didymocarpa is a very singular species, conspicuous by its strong corymb of flowers, and when in fruit remarkable for its evidently bilobed didymous silicle, which is orbicular or inflated. On the Rocky Mountains, " from lat. 52° to 57°, and in all probability southwards to the sources of the Platte, it seeks the deep sand-banks and sand-beds, wherever its long fusiform roots may find easy lodgment.

Of all the genera of the Cruciferous order, Draba has in North America the greatest number of species. Thirty belong to this continent, and of those the greater part are Arctic and subArctic plants. Confined to high northern latitudes, and scattered over the islands and shores of the Arctic Seas, we have the D. algida, alpina, pauciflora, micropetala, oblongata, corymbosa, lapponica, and stellata. In the extreme north is also found the D. glacialis; but this has likewise an Alpine resi dence southwardly, on the summits of the Rocky Mountains, to which the others apparently do not stray. The Draba lævigata has been seen as yet only at the extremity of North West America. Common to the sub-Arctic as well as Arctic regions are other Drabas more likely to be fallen in with by the Canadian botanist. The D. muricella exists in the north, and in Labrador. The D. incana, stretching along the coast of the Frozen Sea from Unalaschka to Labrador, can be

gathered plentifully on the north shores of the St. Lawrence. The D. hirta, is common on the rocky islands of Lake Superior; and the D. glabella, lutea, and nemoralis, approach the confines of Canada West. Hooker gives the island of Montreal as a habitat of the Draba muralis of Linnæus. The Draba oligosperma, a native of the banks of McKenzie's River, appears to have been collected by Nuttall on the summit of lofty hills near the sources of the Platte. The Rocky Mountains afford: near their heights some Drabas peculiar to the range; the D. densifolia at the sources of Lewis's River, the D. rupestris levipes, crassifolia and aurea, on the same ridges, as far north as lat. 570. The strictly southern species are fewer in num

D. arabisans is found near Lake Champlain, and in the States of New York and Michigan, crossing to the north shore of Lake Superior. Five or six others are dispersed only over the Central and Western States; but the D. verna, with bipartite petals, which may be reckoned among these, sometimes may be seen decking the hill-sides and fields of our province.

The fifth tribe of Crucifera, the Alyssinea, commencing with Vesicaria, continued in Draba, will end with Cochlearia, a genus pre-eminently Polar, as encircling to a great extent the Great Polar Basin, representing the great flowering classes almost at the very limits of vegetation, and bearing the standard of Flora nearly to the axle of our sphere. Three Cochlearia belong to Russian America, and four to our Arctic coast. These latter are the C. Anglica, fenestralis, officinalis, and Danica. C. trydactylites is said to occur in Labrador, and C. Greenlandica pertains to Greenland. Diffused laterally like a belt or girdle, this genus, assisted by other plants of a similar constitution, and the Mosses and Lichens, helps to produce an identity of vegetable growth and covering to the earth in the highest northern latitudes, on the European, Asiatic, and American shores.

The genus Camelina, from which the sixth tribe of Cruciferæ, the Camelineæ, takes name, has but one species native of North America, the C. barbareafolia, which has been found only on the Russian territory on the north-west coast. The C. sativa must be an introduced plant, and is probably working its way westwards and northwards with the progress of civilization.

Braya, with the four following genera, has been placed by Torrey, with some degree of doubt, in the tribe Camelinea The Braya alpina is obtained on the Rocky Mountains, from

latitude 52° to 570; and the B. glabella and pilosa are the d'scoveries of Sir John Richardson, on the shores of the Arctic Sea, the latter having been met with only at the outlet of McKenzie River.

Platypetalum purpurascens has a habitat extending from McKenzie River to Spitzbergen, and the P. dubium is a species of Melville Island.

Two Eutrema, the E. Edwardsii, upon which R. Brown founded the genus, and the E. arenicola, are both Arctic plants. The former was discovered first on Parry's voyage to Melville Island, and was afterwards collected, along with the second, on the Arctic coast, on each side of the McKenzie, by the travellers Franklin and Richardson.

A single species of the genus Platyspermum, the P. scapigerum was the discovery of David Douglas, at the great Falls of the Oregon or Columbia River.

The Subularia aquatica of Linnæus has been procured from the borders of ponds in Maine by Nuttall.

Two tribes having the silicle compressed, contrary to the narrow septum, will now complete what has to be said regarding the SILUCULOSE and their distribution. These are the Thlaspidineæ and Lepedineæ.

The Thlaspi arvense of Linnæus, as well as the Thlaspi alpestre, are commonly met with in old waste grounds in Canada. Both I believe to have been introduced, for neither of them occur to my knowledge in the newly-settled or the uncultivated and wilder parts of the country. The Thlaspi alliaceum is rare. The indigenous species T. montanum is found from Canada to the Arctic zone; and the T. cochleariforma, closely resembling it, occupies a western position, about the head waters of the Oregon. The T. tuberosum, remarkable for its tuberiferous. roots, does not appear to have been met with in Canada or the North. It was discovered by Nuttall in Western Pennsylvania.

Hutchinsia, another genus of this tribe Thlaspidinia, has a species, the H. calycina, from the Rocky Mountains, in lat. 520 to 57° a variety of it is noted as native in Kotzebue's Sound.

The Lepidium ruderale occurs frequently throughout the British Possessions from Hudson's Bay to the Pacific Ocean, preferring waste places like the Thlaspi. The L. campestre, common about fields and gardens, is a weed introduced from England. Species are met with passing the Rocky Mountains into the

Oregon Territory, such as the L. integrifolium and L. montanum. The Lepidium Menziesii, first known on the north-west coast, was also gathered by Drummond in the Rocky Mountains, afterwards by Nuttall on the same ranges farther south. We can merely name the Californian species, the L. oxycarpum and L. latipes, discovered by Douglas; the L. Californicum, lasiocarpum, and nitidum, by Nuttall..

The Capsella bursa-pastoris, or Shepherd's Purse of the old countryman, is well diffused over the whole country to the roots of the Rocky Mountains westward, and to Great Bear's Lake northwards. About this, our well-known old friend, there is never any mistake. The declared plague of the pasture, and detested by the industrious gardener, the bursa-pastoris nevertheless gladdens our eye with its homely and home-like look, reminding us of early days and all their associations, the country road, the cotter's kale-yard, and other long-forgotten scenes.

The third division of our order, the Nucamentosa, containing the ninth tribe, the Isatidea of Decandolle, furnishes us with but one genus on this continent, the I. thysanocarpus of Hooker, of which all the species lie west of the Rocky Mountains. The I. curvipes, upon which the genus was founded, was discovered by Douglas at the Great Falls of the Columbia; and the I. oblongefolius was first discovered by Nuttall as being native of the same country, but much lower down the river, at the junction of the Willamet. Four others are Californian, the I. elegans and pulchellus of Fischer and Meyer, and the I. crenatus and laciniatus of Nuttall.

In the fourth division Lomentacea is the tenth tribe, Cakiinea, in which we have the genus Cakile. The single species, C. Americana, is a strange-looking plant, known in English as the Sea Rocket. The pods are constricted, and have transverse separations, forming one celled, one seeded joints. It is not apparently a common plant, but occurs near the sea, and on the shores of the great lakes of Canada. I have seen it on sand along the north bank of the great St. Lawrence River, from the Gulf up as far as the Saguenay. Its fleshy leaves no doubt enable the Cakile, although on a smaller scale than the purely succulent orders, such as the Cacti, &c., to assimilate much of its sustenance from the air; nature thus, by wise modifications of structure, compensating liberally in one way, for what may be wanting or stinted in another. I have been sometimes surprised at the fresh

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ness of the Cakile in a dry sand, where most other plants of the same order would have withered and perished.

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In taking leave of this most useful and interesting order, I may with propriety quote from Sir John Richardson's very able observations at the end of his "Journal of a Boat Voyage," published in 1851. Regarding Polar plants, he says:-" Of the Polar "plants, amounting to 91 species, which inhabit Melville Island, "the shore of Barrow's Straits to Lancaster's Sound, and the "north coast of Greenland, between the 73rd and 75th parallels "of latitude, about 7ths range to Greenland, Lapland, or Northern "Asia. Of the remainder some have been gathered on the shores "of the Arctic Sea from Baffin's Bay to Behring's Straits, and it "is probable if these high latitudes were fully explored, the Flora "of the entire zone would be found to be uniform. Some of the "more local plants will perhaps be ascertained, on farther acquaintance, to be mere varieties altered by peculiarities of "climate. That the Flora as well as the Fauna of the high "northern latitudes is nearly alike in the several meridians of Europe, Asia and America, has long been known; and even "when to some distance south of the Arctic circle, we find that "this law is superior to the intrusion of high mountain chains, "and is but partially infringed upon." Further on he observes: "The families of Polar plants which are most rich in species are "the Cruciferæ, Gramineæ, Saxifrageæ, Caryophyllex and Com"positæ. Of these, the Saxifrage are most characteristic of "extreme northern vegetation. All of them that inhabit the 74th "parallel in America are found also in Spitzbergen, Lapland or "Siberia; and even the Polar species are twice as numerous as "those which exist in the wide district which 'Gray's Flora of "the Northern States' comprehends; and we may add, that the "plant which Humboldt traced highest in the Andes, was a "Saxifrage. The Caryophylle and Cruciferæ, which vie with "the Saxifrageæ in number on the 74th parallel, include many of "the doubtful species above alluded to."

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There is no doubt every reason to believe that Sir John's words as to the unlucky multiplication of species through the separation. of varieties will some time or other prove true, not only in the plants of the Arctic zone, but also in those further south. More extended acquaintance with both will correct our knowledge in that particular. Able monographs amongst American and European botanists will do this work, so much required.

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