Distribution
The exact limits of the distribution of the sycamore are difficult to define, as the tree has been extensively planted for centuries outside of its original home, which in Europe may be roughly described as the great central chain of the Pyrenees, Alps, and Carpathians, with the mountains and hilly districts radiating from them in all directions. It is truly wild in the Pyrenees, and reaches its western limit in the Iberian Peninsula in the Cantabrian Mountains, being absent from the greater part of Spain and all Portugal.’ It occurs in all the mountainous and hilly districts of France except in the north-west; in the Alps generally ; in the mountains of Germany, as far north as the Harz Mountains; in the Carpathians, Apennines, mountains of Sicily, Dalmatia, Bosnia, Servia, and in the mountains of Thessaly and Epirus in Greece.2 In Russia it occurs in the provinces along the Black Sea, extending inland along the banks of the great rivers, and in the mountains of the Crimea. It is widely spread in the mountains of Asia Minor, Armenia, and the Caucasus,? where it grows at all altitudes from sea- level to 4000 feet. Its extreme easterly point is near Astrabad, south-east of the Caspian Sea, about lat. 37°.
The tree is not a native of the British Isles, North-West France, Belgium, Holland, the North German plain, Denmark, Scandinavia, or the greater part of Russia. In these countries the sycamore, however, flourishes, and is extensively cultivated, reaching its northerly limit as a planted tree, according to Schübeler, in Norway and Sweden about lat. 64°.
It is usually met with, in the wild state, as an isolated tree or in small groups, being only known to form pure woods, and those of no great extent, in the Thuringian forests. It does not occur naturally on light soils, on heavy clay soils, or on wet ground; and apparently, in order to compete with other trees, must grow on a soil rich in mineral constituents, such as often occurs in valleys or ravines, or in pockets here and there in forests, where the soil is generally poor. It forms a part of the great beech and silver-fir forests; but reaches higher than either of these species on the mountains, where it dwindles to a sub-alpine shrub near the timber line. In the Bavarian forests it grows in the zone between 1000 and 4400 feet altitude, and a peculiar form occurs, with twisted curved branches, which Dr. Christ* has not observed elsewhere. In Switzerland,‘ it ascends to 5300 feet, and is most plentiful at Sernfthal above Elm. In France it ascends to about 5000 feet, and is most generally met with in the beech forests, its abundance and flourishing condition being considered a sure index of a fertile soil.
The sycamore has not been found in the fossil state in the British Isles. Clement Reid® hazards the suggestion that it was perhaps introduced by the
1 Willkomm, Pfanzenverbreitung auf der Iberischen Halbinsel, 94 (1896).
2 Halácsy, Consp. Fl. Græcæ, i. 285 (1900).
3 Radde, Pflanzenverbreitung in den Kaukasusländern, 175 (1899).
4 Christ, Flore de la Suisse, 278, 279 (1907).
5 Origin British Flora, 16 (1899).
