SPRUCE AND BALSAM FIR TREES. 11 
Engelmaim spruce was published in 1863, since which time writers 
on North American trees have generally agreed in maintaining the 
different wild forms of this tree as one species. 
Three or four garden forms of this spruce have been designated 
as varieties. 1 They are distinguished by their crown habit, size, or 
the color and length of the leaves. 
DISTINGUISHING CHAKACTEEISTICS. 
In dense stands Engelmaim spruce has a straight, clean, slightly 
tapering trunk with a close, very short, narrowly pyramidal crown 
of small branches; the upper-crown branches are exceedingly short 
and form a narrow spirelike point. Such trees are from 80 to 100 
feet or more in height, and from 18 to 36 inches in diameter. Larger 
trees occur sometimes, but they are now rather rare. When growing 
singly or in an open stand, Engelmann spruce has a similarly shaped 
but longer crown, with drooping lower branches often extending 
down to the ground. The middle-crown branches are horizontal and 
the top branches strongly upright. Trees of this form are usually 
from 60 to 80 feet high, with very tapering trunks, and if exposed 
to heavy winds the lower branches are often long and stout. From 
all of the main branches hang numerous tassel-like side branchlets 
which give the tree a very compact appearance. At high altitudes, 
Engelmann spruce is often not more than from 2 to 4 feet high, when 
the spikelike stem bears only a few short, densely leaved branchlets, 
while enormously long branches grow from the base of the stunted 
trunk and spread over the ground. The trunk bark becomes scaly 
even on rather young trees. On older and larger trees it is thin, dark 
purplish-brown or russet-red, and outwardly composed of very loosely 
attached small scales. 
The foliage of Engelmann spruce is a deep blue-green, that of 
some trees being decidedly silvery or whitish. This silvery or 
whitish tinge is very marked on young trees, but occasionally large 
and moderately old trees still retain it. The 4- angled leaves (PI. 
IV, c) are rather soft to the touch, usually about an inch in length, 
but often longer, especially on young, vigorous trees. The leaves 
are spreading on young twigs and on those which do not bear cones, 
while on cone-bearing twigs (PI. IV) they are commonly crowded 
and usually shorter; they are also often curved so as to appear to 
grow mainly on the upper side of the branchlet. The point of the 
leaf is, as a rule, characteristically short and flattish, the short types 
of leaves exhibiting this more strongly than the longer ones (PI. 
1 Picea engelmanni griseifolia Sudw. (=" P. e. glauca"), P. e. argyrophylla Sudw. 
(=" P. e. argentea") , P. e. minutifolia Sudw. {=" P. e. microphylla Hesse"), and P. e. 
fendleri Henry are the garden varieties found in cultivation. 
