24 Nr. 2. C. H. OSTENFELD and C. SYRACH LARSEN: 
to the great height, and L. occidentalis in its habitat also 
grows slender, regular trunks with short lateral branches, 
and slender, pyramid-shaped crowns. 
In April 1826, Davin DouGLas made a journey up the 
Columbia River, and in the district lying in the fork made 
by the junction of the River Spokon and the Columbia, 
on his way to Fort Colville, he entered the great, fertile 
pine-forests, where L. occidentalis attains its greatest devel- 
opment. He did not differentiate it from L. decidua, which 
is later described, but he admired its imposing dimensions 
and the excellence of its timber, writing in his journal: 
»I measured some thirty feet in circumference; and several 
which had been levelled to the ground by the late storms, 
were one hundred and forty-five feet long, with wood per- 
fectly clean and strong«, and he also states that they were 
the commonest conifers met with in the district (Com- 
panion to the Bot. Mag. II, 1836, p. 109). The tree is a 
splendid one, surpassing all the other species of larch in 
height and girth where it attains its best development, and 
possesses a Shape and timber as valuable as the best of 
the other species. 
Its area of distribution lies like a ring around the 
lowland, formed by the central part of Washington and 
the northern of the Oregon up to the northern side of 
the Blue Mountains. This is the Great Plain of the Colum- 
bia River. It is most extensively distributed towards the 
north-east in the Rocky Mountains; the line then takes a 
north-westerly direction towards the Cascade Mountains, 
which it follows southwards until a little south of the 
Columbia River, where it bends eastwards and continues 
— in somewhat straggling groups, it must be confessed — 
until it again reaches the Rockies. 
