The Rocky Mountain Plant Guide

"The Rocky Mountains are not one continuous, homogenous range formed at the same time by the same processes. The more than 100 separate ranges can be divided into the Northern and Canadian Rockies, Middle Rockies, and Southern Rockies separated by plateaus and basins. Each region has its own distinct topography, geology, and ecosystems. Within each region, altitude, precipitation, and exposure create broad, well-defined life or bio zones with numerous unique habitats and vegetative associations, or communities, of plants. In this book, wildflowers and shrubs are lumped together, with trees in a separate section. Herbaceous perennial wildflowers freeze down to the roots ever winter and sprout in the spring. Annuals die in the fall and depend on seeds to germinate in the spring. Shrubs have woody stems and branches and reach 3-10 feet tall (1-3 m), sometimes developing into small trees. Trees usually have a single trunk and are greater than 15 feet tall (4.5 m). Herbaceous trees and shrubs lose their leaves in the autumn (aspen, cottonwoods) while evergreen species retain their leaves (pine, spruces, and firs)"--