The intermediate temperate region, which ex tends from the southern fringe of the Arctic region to the northern limit of the Mediter ranean-Caucasian, is characterized first by more varied and numerous perennials, which, as the northern limit recedes, become taller and among which are both shrubs and trees also increasing in size and height; and by annual species which also increase in number and variety south ward. These species, of which many appear to have migrated westward from Asia, and which are very prolific of seed, quickly take possession of abandoned land, and, being of fairly rapid growth, readily adapt themselves to wide dif ferences of climate, withstanding on the one side the rigors of high latitudes and elevations, and on the other, the droughts of arid sections. In the western part, forests are the dominant fea ture; in the eastern, steppes. Throughout the whole forest sections of this region, eone-bearing trees predominate. In the far north they exclude all other species of trees, but as the latitude of central Norway is approached, ash, and alder appear. The forest of southern Norway, the Baltic Provinces of Russia, and especially of Denmark, though still largely coniferous, are liberally sprinkled with oak and beech and the three deciduous species mentioned. Throughout Germany and adjoining Russia, France, and Aus tria, the leading trees are still the conifers (pine. larch. fir), among which the others mentioned are found, mingling with which are elm, maple, aca cia, and poplar.
The steppes. not unlike the' great western prairies of North America, are treeless plains that extend across the continent from the east ern borders of Holland to and beyond the Ural Mountains. In Russia, where only the name is properly used, these steppes blend with the tundras of the Arctic region, and on the south with the more northerly forests of the Black and the Caspian Sea districts. Since their climate— long severe winter, short vernal season, and pro tracted parching summer—largely precludes the growth of perennials except along the river basins, which are often wooded, their flora con sists of annuals—grasses on the arable soils, especially north of the Black Sea forests, salt loving plants in the saline sections north of the Caspian Sea. In the northern part of both forest and steppe districts Arctic species mingle with the hardier temperate plants, in addition to which mustards, parsley's, buttercups, thistles, legumes, erowbur•ie4;, brambles, bilberries, and their allies are met with in increasing frequency southward. In the southern part, these last mentioned blend with gorse, shrubby legumes, heaths, lobelias, dianthus, etc., which are most numerous toward the west, while mints, angelica, currants, rhubarb, and their congeners are more abundant toward the east. This region embraces
the great agricultural sections of Europe—the vast grain, flax, and grazing areas of Russia; the cereal, root, and hay fields of Germany, Nor way, and Sweden; and the general farming sec tions of Germany, Denmark, 'Holland, Belgium, the British isles, and northern France. Except on the remote northern border, grasses and le gumes, the bases of successful husbandry', thrive remarkably and materially influence the pros perity of the residents.
The Mediterranean-Caucasian—the fruit, flow er, and vegetable—region, which extends from the Atlantic Ocean to the Caspian Sea, thus includ ing all countries on the warm southern border of the continent, is noted for the great diversity and wide economic importance of its flora, which, it is estimated, comprises 85 per cent. of all European species. Annuals and biennials ap pear in large numbers, the long season of growth favoring their perfect development. The forests are far more mixed than in the other two regions, and contain in addition to the above mentioned species, which appear at greater or less altitudes, evergreen and cork oak, chestnut, sycamore, mountain-ash, plane, and cypress. Of the plants valued for their flowers may he found numerous relatives of the rose, carnation, hibiscus, lilac, tuberose, crocus, lily, colchicum, iris, and many others. in this region more than in either of the others the flora is augmented by exotic spe cies, especially such as have been introduced by man. With the migration of the human race and tne extension of commerce westward, useful plants have been purposely carried and useless ones undesignedly transported to regions far dis tant from their homes. Of such antiquity are many of the Asiatic and African contributions to this flora that many species have become so settled in their new residences as to be considered indigenous. Of these, perhaps the best known are the fig, peach, apricot, walnut, orange, olive, pomegranate, grape, quince, cherry, mulberry, pistachio. melon, leek, onion. sugar-cane, cumin. and cotton. But southern Europe has been not merely a greedy absorber of introduced species; it is a lavish distributer as well. Its trees, fruits, vegetables, and flowers have been carried to every quarter of the globe that European com merce has reached. Save only the plants of Norway's western coast, few in number, but of great adaptability to foreign climates, the spe cies of no other region compare with those of southern Europe as wanderers. So general has been their distribution that no traveler in any country visited by civilized man can go far with out meeting plant acquaintances; if not among the useful species. then among the weeds of this Mediterranean-Caucasian region. See para graphs on flora of the various countries; also DISTRIBUTION OF PLANTS.