E U U P E G91 of genera and species represented iu the European floras. Several districts have only been partially explored by the botanist ; he not unfrequently finds it difficult to decide whether a given plant has a right to be admitted into his lists ; and he is naturally more interested in estimating the comparative richness of his scientific regions than of such conventional areas as the continents. Hinds, reckoning all known species of plants at 134,000, allows 11,200 to Europe : while Frieclrich Nyman, in his Kylloge Florce Europcece, 1854-1855, gives 1115 genera and 9738 species according to Fries s classification, and assigns 883 genera and 8104 species to the dicotyledons, 206 genera and 1544 species to the monocotyledons, and 26 genera and 90 species to the acotyledons. In all probability the numbers, especially of the species, are below the truth. The total number of so-called useful plants cultivated in European gardens is stated by Professor Gb ppert at from 2400 to 2500 ; but a large proportion of these are mere exotics. The extent, indeed, to which this is the case, even with many species of wide distribution, is one of the most strik ing facts in botanical geography. The vine, the olive, the fig tree, and the mulberry were not improbably brought from Syria or Asia Minor by the Greeks ; the Arabians in troduced the cotton plant ; the walnut and the peach are originally from Persia, the apricot from Armenia, and the sugar-cane and the orange from China. The leek and the onion, the mustard plant and the cumin, the laurel and the myrtle, are all Asiatic. For the pomegranate we are probably indebted to the Phoenicians, and the quince still bears the name which it received from the town of Cydonia in Crete. The cypress is a native of the neighbourhood of Herat, the plane tree of the Taurus, the chestnut possibly of Armenia. Lucullus, the conqueror of Mithradates, brought the first cherry-tree to Europe ; and some less famous Roman of the first century after Christ was the in troducer of the pistachio. Maize, tobacco, and the potato are well known to be of American origin, and the same is the case with the agave and the opuntia, two of the most char acteristic plants of the Mediterranean region. The scarlet oak was brought from North America to England in 1691; the cedar of Lebanon was first planted in British soil in 10 S3; and among recent additions are the Douglas pine from the Rocky Mountains, the deodara from the Hima layas, the Wdlinytonia gigantea from California, and the Eucalyptus Glolidus from Australia. The last is being planted in thousands in southern Europe, and has produced a greater sensation than perhaps any other botanical stranger. It would be easy to continue the list to an indefinite ex tent, and it would require to be supplemented by a list of floral additions that have taken place within historic time without the intentional intervention of man. This second cl rss is also a numerous and continually increasing one. 1 Iu the neighbourhood of Port Juvenal, near Montpellier, 487 exotics from America, Asia, Australia, and New Zea land were collected by Godron, and of these 52 species were new to science. The Anacharis Alsinastrum or Elodea cttnadeiisis, 1 * from Canada, now luxuriates in the rivers of England and Prussia, where it was quite unknown about 1850; and the Eriocaidon septdngulare has found a new homo in the streams of Ireland. In the former instance the rapid diffusion is all the more remarkable as the plant is dioecious, and only one sex has reached Europe. It will be readily understood that if the introduction of new species into the continent is of frequent occurrence, the migration of indigenous species from district to district must be more 1 Set; Zeyss, Versuch einer Geschichte der PJlanzen- Wandcrung ; BIyth, Essay on Immigration of the Norwegian Flora during alternat ing Rainy and Dry Periods, 1876 ; Robert Brown, in Geographical Magazine, 1374. a bee K. Bolle, in Zcilschrift far Erdk. zu Berlin, 1865. frequent still. The plants of the higher regions are often carried down by the rivers, and effect a permanent settle ment in the plains ; and from time to time a foreign army leaves the seeds of a foreign flora on its camping-ground. Thus the Campanula pusilla, for example, has floated down from the Alps to Strasburg, and the Bunias orienlalit has grown in the Bois de Boulogne since the Cossacks were there in 1815. There is a limit of course to such introduc tions and immigrations : of plants as of men it is equally true non omnes omnia possunt. The most important economical position is held by the Culti- cereals. Wheat is most extensively cultivated in Russia, vated Austria, the Danubian principalities, France, England, and I lailtj *. Germany. The parallel of 57 or 58 may be taken as its northern limit, though it is grown as far north as 65 C 3 and is found to ripen in the island of Dyro in 69 5 . Spelt (Triticum Spelia} is mainly cultivated in south-western Germany, Switzerland, and Belgium. Barley is cultivated in West Finmark as far as 70, and is part of the usual crop in all countries of the continent. Oats are more frequent in the central and northern regions; their practical polar limit is 69 28 , though they have been known to ripen at Hammerfest in 70 37 . Rye is an important crop in nearly all the great grain-growing countries, but it is especially in favour in the east and north; its northern limit is between 69 and 70. Maize has been grown in 63 15 , reaches its practical limit in 59 55 , and is exten sively cultivated only in the southern parts of the continent. Sorgho (Sorghum saccharatuni) from China and a few other foreign cereals have been successfully introduced, but are hardly anything more than agricultural curiosities. The next place belongs to the potato, which has spread over an enormous area in central and northern Europe. It has been grown as far north as the island of Magero in 71 7 N. lat., or about four miles S.E. of the North Cape. The greatest producers are Germany, Belgium, Sweden, the Netherlands, Norway, and Switzerland. A considerable variety of legu minous plants are grown in Europe either for their fruit or forage beans, pease, lupines, clover, lucerne, sainfoin, (fee. The common pea (Pisum arvense) and the common bean (Vicia Faba] have their northern limits respectively at G4 41 and 67 17 . A species of lupine (Lupinus linifolius) furnishes a substitute for coffee both in Norway and Tyrol. The vine can be grown without protection in southern Scandinavia, and has been known to ripen its grapes in the open air at Christiansund in G3 7 ; but its cultivation is of no importance north of 47J on the Atlantic coast, 50 on the Rhine, and from 50 to 52 in Russia. The following is the average wine-production of the several countries: France, 42,000,000 hectolitres (or 924,000,000 gallons); Italy, 30,300,000 ; Austria-Hungary 23,000,000; Spain, 20,000,000; Germany, 4,440,500; Switzerland, 1,155,000; Greece, 1,150,000; Roumania, 1,000,000; Russia, 614,000. A special Greek variety of vine is the source of the currants of commerce ; it is culti vated in the Peloponnesus, Cephalonia, Zante, Ithaca, and Santa Maura, and yields an annual average export of 128,000,000 Q). The olive, with its double crop, is cue of the principal objects of cultivation in Italy, Spain, and Greece, and is not without its importance in Portugal, Turkey, and southern Austria. The average total of the oil harvest in these countries amounts to about 140,000,000 gallons; and of this Italy alone produces about 66,000,000. Besides the turnips and other roots which furnish so much of the winter-fodder required by the northern tanner, the beet holds an important economic position in central Europe as a producer of sugar. Tobacco is extensively grown from Sicily to Sweden, but its cultivation is forbid den in England, Spain, and San Marino, and in Austiia it is
a state monopoly. Its northern limit is about 63 26 . It