A tree 100 to 200 ft high, with a narrow, pyramidal head, and a trunk sometimes 6 to 8 ft in diameter; bark scaling. On some of the young trees at Kew the young shoots are glabrous, on others downy. Leaves 11⁄4 to 13⁄4 in. long, scarcely distinguishable from those of common larch. Cones oblong to egg-shaped, about 11⁄2 in. long, 3⁄4 in. wide; the scales thin, rounded, slightly reflexed at the margin. The cone is rendered very distinct by the conspicuous tongue-like apex of the bracts protruding horizontally 1⁄4 in. or more beyond the scales. Bot. Mag., t. 8253.
Native of western N. America, from British Columbia southwards. In N. Montana, in the neighbourhood of Flat Head Lake, it is, according to Sargent, sometimes 250 ft high. It is, therefore, the most magnificent of all larches, and produces a fine timber. It was introduced to Kew in 1881 by Prof. Sargent, and trees are now over 60 ft high, with shapely trunks and short branches, in general appearance very like the common larches close by, except for the prominent bracts of the cones alluded to above and the more slender habit. For many years these were the only trees in the country, but a considerable quantity of seed was later imported from which thousands of thriving young trees were raised. It is, however, no longer planted in the British Isles as a timber tree, being of slower growth than the common and Japanese larches.
There is a specimen at Kew from the original introduction of 1881 referred to above which was planted in 1889 and now measures 72 × 41⁄4 ft (1971) and another.pl. 1903, of 75 × 5 ft (1971). Other examples arc: National Pinetum, Bedgebury, pl. 1924, 70 × 73⁄4 ft (1965); Woburn, Beds, pl. 1929, 75 × 33⁄4 ft (1970); Bayfordbury, Herts, 85 × 43⁄4 ft (1968); Edinburgh Botanic Garden, two trees pl. 1909, 62 × 4 ft and 60 × 51⁄2 ft (1967).
Inhabiting the same geographical region as L. occidentalis is:
L. lyallii Parl. – This is a tree 40 to 50, occasionally 80 ft in height. Its cones resemble those of L. occidentalis in having conspicuously protruded bracts, but it is quite distinct in other respects. The young wood is densely woolly, almost felted, the leaves four-sided, cones up to 2 in. long, with the scales distinctly fringed, pink when young. A few small plants have been introduced, but they have a miserable appearance, and the species does not give any promise of succeeding in the British Isles. It occupies a small area in the Cascade and northern Rocky Mountains, at subalpine elevations.