The great continent of Asia, of which Europe, as we have seen, is but a peninsula, can be divided into a series of zones, distinguished alike by climate and by vegetation. To the north we have the cold tundra region, passing to the south into the forest region. The Asiatic forest region is continuous with that of Europe, but while the European forest extends southward till Mediterranean conditions intervene, close to the sea of that name, the Asiatic forest has its southern limit in about the latitude of London. To the south of the Asiatic forest stretches a zone of steppes passing into desert, and even into tundra in the elevated regions of Central Asia. The steppe region, as we have already indicated, enters Europe by way of Russia and pushes a long arm up the Danube into Hungary.

South of the Asiatic steppes and deserts comes an interrupted band of warm temperate or tropical forest, luxuriant to the east where there are summer rains, scanty and scrub-like to the west, where Asia meets the Mediterranean.

The steppes and desert of Asia are populated, scantily enough, with wandering pastoral nomads, who constantly tend to overflow from their own region into those of the surrounding agricultural populations. These agricultural populations are concentrated in three areas, all specially favoured by nature. To the east the summer rains, the luxuriant indigenous flora, and the presence of great river valleys, that is, of naturally fertile regions, led to the early establishment of agricultural populations in China and India. Further to the west, the fertile valleys of the Tigris and Euphrates early saw the founding of a great civilisation. This region, the Mesopotamia of geographers, is very near the third area, the Mediterranean, though far enough removed to have a very scanty rainfall, which made irrigation a necessity for agriculture. Its inter-relations with the Mediterranean must have begun early, and, remembering that part of the Mediterranean itself is in Asia, we need not stop to discuss the vexed question as to whether the Mediterranean civilisation was largely indigenous, or originated in the continent of Asia. It is often difficult to ascertain whether plants which have long been grown in the Mediterranean area, and are well-fitted to it, are really indigenous there, or were brought to it from the Mesopotamian countries. There is much similarity of climatic conditions, and for our purpose it is sufficient to note that the cultivated plants of the Mediterranean basin fall into three main categories. There are, first, the plants specially adapted to its climate; these are either native or were introduced from the countries close at hand. Second, there are many plants, much less perfectly adapted to conditions of drought, and therefore often demanding irrigation in summer, which were introduced from the Far East, after they had been cultivated there for long periods. Thirdly, and much fewer in number, there are the plants introduced, at a relatively late date, from America.

Of the first group the most important are the cereals barley and wheat, and the olive and the vine. These four have been known in the area from the earliest times, and they still form the basis of the diet of Mediterranean peoples. Bread, olive oil to replace the butter used by pastoral peoples, wine as a beverage, with fresh grapes and the dried forms of raisins and currants, these early made life possible in the Mediterranean area.

Barley is older than wheat, and is more productive but less valuable. It is now largely grown in the basin of the Mediterranean as a food for horses, instead of oats which, like rye, is a cereal not well suited to the Mediterranean climate. As a bread plant it was early replaced in the Mediterranean by wheat, but it is still used to make bread in some other parts of Europe, e. g. in Scandinavia, and is also of importance outside the Mediterranean as the origin of fermented beverages.

Wheat is the most valuable bread plant which exists, both on account of its proteid content and on account of its digestibility. It demands a warm dry period for ripening, with much sunshine, and is well adapted to Mediterranean conditions. Here it is sown in the autumn, to enable it to take advantage of the “early and the latter rain,” i. e. the autumn and spring rains, and ripens early before the excessive drought of summer sets in. Like barley it has always been associated with plough culture, the animal used being the ox. According to most authorities plough culture originated in Mesopotamia.

The vine and olive are apparently both indigenous to the Mediterranean, and both are well adapted to withstand drought. In regard to the vine there are several interesting points. To the traveller from the north it is most familiar in France or Germany, where it is grown on sunny slopes, usually terraced to prevent stagnant water from lying. In the Mediterranean, on the other hand, it is planted in hollows, or low-lying ground, which permits of the collection of water, for it will receive no summer rain. The vintage is more secure than further north, and the resistance to the attacks of parasites is greater, yet, curiously enough, the Mediterranean countries do not produce the finest wines. This seems to be partly because the climate does not permit of the long storage necessary for maturing to take place. The cool cellars, so important in the wine industry further north, are here absent.

To the four plants which we have mentioned we must add such forms as the fig, which if not indigenous was of very early introduction; garlic, greatly valued as a flavouring matter; various kinds of pulse; sesame; millet, once widely grown though no longer important, and flax, known from remote antiquity.