YELLOWSTONE Rules and Regulations 1920

TREES.

In Yellowstone Park, as everywhere in the West, the trees are nearly all "evergreens," or members of the Pine Family. In most parts of the East the forests are composed of broad-leafed deciduous trees.

Lodgepole pine (Pinus contorta).—Sometimes known as jack pine. The most common tree of the Park, abundant at low and middle altitudes and exceeding nearly up to timberline; probably three-fourths of the forest of the Park is composed of this tree. The pines are distinguished from other evergreen trees by having their long slender leaves in bundles of two or more, instead of being attached singly to the branches. In the lodgepole pine there are two leaves in each bundle.

Limber pine (Pinus flexilis).—In the West often known as white pine. Occasional at low and middle altitudes, chiefly on dry, rocky ridges, the trees usually scattered among those of other kinds. Leaves five in each bundle; cones 3 to 6 inches long, green when young, opening when mature; bark blackish, rough.

White-bark pine (Pinus albicaulis).—Found only about timberline. Leaves five in each bundle; cones 2 to 3 inches long, brown-purple when young, remaining closed when mature; bark whitish, smooth. A low, stunted tree.

Firs.—The firs have flat, blunt-tipped leaves 1 to 2 inches long. The cones are borne at the top of the tree and they stand erect on the branches like candles on a Christmas tree; when ripe they fall apart. The bark of the firs is smooth and pale, and scattered over it are numerous blisters filled with liquid resin.

Alpine fir (Abies lasiocarpa).—Common about timberline and also at middle altitudes. Leaves rounded at the tip, not notched, those of the lower branches scattered irregularly on the upper side of the twigs. About timberline usually stunted and often lying flat on the ground; at lower altitudes a fine, large tree.

Grand fir (Abies grandis).—Frequent at low and middle altitudes, especially along streams. Leaves, usually notched at the tip, those of the lower branches arranged in two rows along the twigs. A large tree.

Spruces.—These look much like the firs, but they have sharp-pointed four-sided leaves (about 1 inch long) and rough, blackish bark. The cones are borne near the top of the tree and they droop from the branches; they do not fall apart when ripe.

Engelmann spruce (Picea engelmannii).—The most common spruce, growing with lodgepole pine and Douglas fir, at middle altitudes, twigs smooth, not hairy; cones 1-1/2 to 2 inches long.

Colorado blue spruce (Picea pungens).—Rather common, at about 7,000 feet. Twigs finely hairy; cones 2 to 3-1/2 inches long.

Douglas fir (Pseudotsuga mucronata).—Sometimes known as red fir. Common at middle altitudes. Leaves blunt-tipped, about an inch long, flat; bark dark and rough; cones scattered all over the tree, drooping from the branches, not falling apart when mature, with long, 3-lobed bracts which project beyond the scales of the cone. Easily recognized by the protruding bracts of the cones, a character found in none of our other evergreen trees. A large tree, the most important source of lumber in the West.

Western red cedar (Juniperus scopulorum).—Common at low and middle elevations, on rocky slopes. Closely resembling the common red cedar of the East; leaves very small and scalelike, attached by 2's or 3's and closely appressed to the twigs; fruit blue and berry like; bark brown, easily peeled off in long shreds. The creeping juniper (Juniperus sibiarica), which is common at middle altitudes, is closely related. It is only a low shrub, however, and has needlelike leaves half an inch long or shorter which spread from the twigs.

Aspen (Populus tremuloides).—Sometimes known as quaking aspen or quaking asp. The only common broad-leaf tree; frequent on moist slopes at lower altitudes. A small, slender tree; bark smooth, whitish; leaves rounded, finely toothed. The leaves are on such slender stalks that they are kept in motion by the least breath of wind.

Narrow-leaf cottonwood (Populus angustifolia).—Occasional along streams at low altitudes. A large tree with rough, pale bark; leaves resembling those of a willow, narrow, sharp pointed. The small seed pods contain numerous seeds, each of which bears a tuft of white hairs or "cotton."

Water birch (Betula fontinalis).—Usually a shrub but sometimes a small tree, growing along streams. Bark smooth, brown; twigs sticky; leaves broad, sharp pointed, coarsely toothed; flowers in catkins; fruit a small cone, which falls apart easily. Alders also grow along streams, but they are shrubs, never attaining the dimensions of trees. They look much like birches, but can be distinguished by the fact that their fruit cones are hard and woody, and do not fall apart like those of a birch.

PLANTS OF THE PARK.

The National Park Service has in course of publication a popular account of the plants of Glacier National Park. This contains illustrations of all the conspicuous plants, with brief descriptive notes. Most of the common flowers of Yellowstone Park are found also in Glacier Park, consequently this publication will be found very useful by visitors to the former park who are interested in learning the names of the plants.