. The Evergreen .Trees oe Coeorado. 5 
their foliage in a green state over winter or even longer and are 
therefore true evergreens. This is particularly the case in tropical 
countries. But as all the cone-bearing trees of this state are ever¬ 
greens the term as here used is intended to include members of 
the pine and juniper families only. 
The plants of the pine family are chiefly characterized by the 
fact that their seeds, instead of being contained during all stages 
of growth in wholly closed seed cases, as in other seed-bearing 
plants, are at first born naked on the scales of cones. The scales 
of these cones become dry and more or less woody and hard 
according to their thickness and form the familiar dry, scaly cones 
of such trees. 
Another character common to the plants of the pine family in 
this region is found in their needle"shaped leaves. These leaves, on 
account of the relatively small surface which they expose and the 
thickness of the epidermis which covers them, are well adapted to 
endure the drying effects of winter so trying to all kinds of peren¬ 
nial plants. 
Most of the cone-bearing trees are possessed of a resinous 
juice or sap which often exudes from wounds and slowly hardens 
in the form of drops or masses of pitch. This .material, when 
gathered from certain pines in the southeastern states, constitutes 
the crude turpentine from which the spirits of turpentine of com¬ 
merce is obtained, the common resin or rosin being left as a 
residue. Timber from pine trees in which the wood has become 
saturated with the pitch of the sap possesses great durability in 
contact with the soil. 
In most species of cone-bearing trees the two sorts of flowers, 
which are separate, occur on the same trees. The stamen flowers, 
those which produce the pollen, are crowded in small catkins or 
cone-like clusters near the ends of the branches. (Plate II, i.) 
The pollen, in the form of a yellow powder, is abundantly produced 
and is carried by the wind to the young pistillate or seed-bearing 
cones. In the vicinity of extensive spruce and pine forests this pollen 
powder is often so abundant, during the blossoming period, as to 
lend the impression that a shower of sulphur has occurred. Soon 
after the pollen is shed these little cones dry up and fall off, hence 
are not commonly noticed. 
The pistillate or seed-bearing cone consists of an axis upon 
which are fastened the scales. The scales vary much in shape and 
texture in different species and furnish some of the principal char¬ 
acters by which the species are distinguished. At the base of each 
scale of the young cone, and lying attached to its upper surface, 
is a pair of ovules. During the flowering period the young cones 
point upward with the scales spread apart. This allows some of 
