This page contains links to websites, books, and phone apps on the flora and vegetation of the northern US Rocky Mountains.
 

Websites

Montana State University Guide to Trees and Shrubs of Montana
Montana Natural Heritage Flora and Vegetation Resources Pages
National Park Service website on vegetation and flora of Yellowstone
National Park Service website on plants of Glacier National Park
National Park Service website on plants of Grand Teton National Park
US Forest Service Trees of Northern Idaho
iNaturalist pages on Yellowstone conifers
iNaturalist pages on plants of Yellowstone National Park
iNaturalist pages on plants of Glacier National Park
iNaturalist pages on common plants of Glacier National Park
iNaturalist pages on fungi, lichens, and mosses of Glacier National Park
 

Books

Plants of the Rocky Mountains
Wildflowers of Glacier National Park and Surrounding Areas
Guide to Plants of Yellowstone and Grand Teton National Parks
Flora of the Yellowstone
Plants of Yellowstone and Grand Teton National Parks
 

Phone Apps

Note that these two excellent phone apps will download all the photos and data that they need when you install them, so you do not need to have phone coverage in the field to use them.

Flora of the Yellowstone Region
Glacier Wildflowers