Prominent on the sides of the Great Basin mountain ranges of Nevada is an open woodland zone of small conifers in which the dominants are pinyon (Pinus monophylla T. and F.) and juniper (Juniperus osteosperma (Torr.) Little). It is apparent even to the casual observer that this dark green zone is almost entirely restricted to the slopes; the grayish sagebrush valley bottoms are treeless except for willows and cottonwoods along the drainages. Also treeless are most of the ridges and peaks which rise above the two or three thousand vertical feet covered by the woodland. Within the dwarf conifer zone, even small valleys, bowls, and flats are open and sage-brush-covered. Around the edges of most of the valleys and depressions, the bronze-green junipers form a prominent border with relatively few pinyons, but higher on the slopes the gray-green pinyon dominates, often in pure strands.