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 white pine (Pinus strobus) is exported from the northern parts of the United States of America and from Canada.
The most important economic species is the well-known white pine, P. Strobus, from its large growth and abundance, as well as the soft even grain of its white wood, one of the most valuable of North American timber trees.
On a deep rich soil P. Strobus attains a height of 150 ft., and trunks without a branch are sometimes found 80 or 90 ft.
P. Ayacahuite, the common white pine of Mexico, spreads southwards on to the mountains of Guatemala, it is a large tree with glaucous foliage like P. Strobus, and yields a valuable resin.
In the North American area Picea alba, P. nigra, Larix americana, Abies balsamea (balsam fir), Thuja canadensis (hemlock spruce), Pinus Strobus (Weymouth pine), Thuja occidentalis (white cedar), Taxus canadensis are characteristic species.