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Postelsia 
highest mountains. Near the sea it often forms 
groves of almost pure growth, the trees standing 
close together, and having very tall slender 
trunks, about a meter in diameter at the base, 
and often unbranched up to a height of thirty 
meters or more. At an altitude of three thou- 
sand feet it is a comparatively small tree often 
clothed with branches to the base. The bark 
of young trees is thin, very smooth and almost 
white, with numerous balsam blisters. In old 
trees it is apt to become thickened, dark and 
somewhat rough. The foliage appears very 
different on the upper and lower branches of 
the tree. Except on fertile and leading shoots 
the leaves are twisted into a somewhat two- 
ranked arrangement. The leaves on the under 
side of the twigs spread laterally, exposing the 
lower side of the stem. On the lower branches 
the leaves along the upper side of the twig are 
small and appressed, so that the spray appears 
flat. On the upper branches, however etite 
leaves along the upper side of the twig are long 
and spreading and the spray is bushy and semi- 
circular in section.. The leaves are very sperm 
