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440 the rachis shows here and there a very slight wing, like that of P. stenoptera, only never serrate in margin. The fruits have oval wings, shorter and broader than those of P. stenoptera, the nut being more beaked than in that species. The veining of the fruit-wings resembles P. caucasica.

Pterocarya caucasica has been found in the northern provinces (Astrabad and Ghilan) of Persia, and in Russian Armenia, as well as in the Caucasus. According to Radde, it occurs in the marshy delta of the Rion in company with Alnus glutinosa, and along the coast of the Black Sea, mixed with oak, beech, and hornbeam. It grows sometimes as a tree, but oftener as a tall shrub, on the banks of streams. It extends up to about 1200 feet only in Kachetia, and is met with as far eastward as Talysch, on the coast of the Caspian Sea, where in damp places it forms the principal underwood. It is not found wild in the interval between the lower Rion on the west and the lower valley of the Alazan on the south side of the central Caucasus, and is again absent from here to the province of Talysch.

Mr. Younitsky of the Russian Forest Service has kindly sent me the following account of the tree in the Caucasus. He says it is only found in certain stations, rarely over 1200 feet elevation, and always in moist or very wet places, to which it is better adapted than even the alder. In the young stage the tree is very delicate and susceptible to spring frosts, requiring shelter when young; and when older does not bear shade well. Very large trees occur, of 100 feet in height and 10 feet in girth, and logs of it are obtained bare of branches for 50 feet, with a girth of 5 feet at the smaller end. It grows very rapidly in youth, making a height of 30 feet in ten years. The wood is light and soft, resembling much that of the lime-tree, and is chiefly used for making boxes and packing-cases. The bark is used for sandals and roofing. The leaves contain a poisonous matter, and when thrown into water intoxicate the fish, which rise to the surface and are easily caught. The tree is rarely cultivated, but is recommended for planting in the wettest situations, where it will thrive better than almost any other tree.

Pterocarya caucasica was introduced into France by the elder Michaux on his return from Persia in 1782. According to Bosc the first tree was planted at Versailles, others a little time after being planted about the Museum in Paris. According to Mouillefert, there are still growing at the Trianon, Versailles, and at the Museum, Paris, two fine specimens which are probably original trees. The tree flowered and produced fruit in 1826 in the park at Malesherbes, according to a note by Gay in the Kew Herbarium. There is a tree 80 feet high and g feet in girth in the Old Botanic Garden at Geneva, which was seen by Elwes in 1905.