Or to take the small but welldefined group of five-leaved pines, all the species of which may be seen growing side by side at Kew under identical conditions: we have the Weymouth pine (Pinus Strobus) in eastern North America, P. monlicola and the sugar pine (P. Lambertiana) in California, P. Ayacahwite in Mexico, the Arolla pine (P. Cembra) in Switzerland and Siberia, P. Peuce in Greece, the Bhotan pine (P. excelsa) in the Himalayas, and two other species in Japan.
The silver fir (Abies sibirica, Pinus pectinata) and the stone-pine (P. Cembra) are quite common; they reach the higher summits, where the last-named is represented by a recumbent species (Cembra pumila).
Pinus cembra " is only remembered, as also Taxus baccata.
The Ayan spruce (Abies ayanensis), the Sakhalin fir (Abies sachalensis) and the Daurian larch are the chief trees; on the upper parts of the mountains are the Siberian rampant cedar (Cembra pumila) and the Kurilian bamboo (Arundinaria kurilense).
P. Cembra is the stone pine of Siberia and central Europe.
The growth of P. Cembra is slow, but the wood is of remarkably even grain, and is employed by the Swiss wood-carvers in preference to any other.
The Cembra is the " zirbel " or " zirbel-kiefer " of the Germans, and is known locally in Switzerland as the " aroile," " aloies," and " arve."
Tree vegetation, which reaches up as high as 6500 and 8150 ft., the latter limit on the north and west, consists of magnificent forests of birch, poplar, aspen, and Coniferae, such as Pinus cembra, Abies sibirica, Larix sibirica, Picea obovata, and so on, though the fir is not found above 2500 ft., while the meadows are abundantly clothed with brightlycoloured, typical assortments of herbaceous plants.
Less known turpentines are obtained from the mountain pine, P. Pumilio, the stone pine, P. Cembra, the Aleppo pine, P. halepensis, &c. The so-called Canada balsam, from Abies balsamea, is also a true turpentine.
In northern Europe this belt is characterized by such species as Picea excelsa (spruce), which extends south to the mountains of the Mediterranean region; Pinus sylvestris (Scottish fir), reaching from the far north to western Spain, Persia and Asia Minor; Juniperus communis, &c. In north Siberia Pinus Cembra (Cembra or Arolla Pine) has a wide range; also Abies sibirica (Siberian silver fir), Larix sibirica and Juniperus Sabina (savin).