Devils Postpile National Monument's vegetation is a montane forest dominated by red fir and lodgepole pine. The monument's proximity to both west and east sides of the Sierra Nevada results in the presence of plants from diverse biological communities. Recent plant inventories documented 360 plant species in the relatively small 798-acre area of the monument. Along the San Joaquin River
Mountain penstemon is a common sight among the summer's flowers.
and the few creeks that flow into it, typical montane riparian vegetation can be found, such as quaking aspen, black cottonwood, alder, and willows. Both wet and dry meadows dot the monument and during the spring and early summer when water is available, a colorful bouquet of wildflowers can be found.