Arizona Game & Fish Dept plant abstracts, maps and illustrations

Arizona Rare Plant Field Guide

Center for Plant Conservation (National Collection of Imperiled Plants with range of Utah)

CNPS Rare Plant Program (California)

Colorado Natural Heritage Program

Colorado Rare Plant Field Guide

Colorado Rare Plant Field Guide 2002 update (PDF)

Colorado State University Herbarium - Rare plants of Colorado

Great Basin rare plants: "Vulnerability of the rarest plants in the Great Basin of Nevada to climate change" poster  (secondary link)

Idaho Fish and Game Rare Plant Field Guide to the Pocatello and Idaho Falls Fields Offices, BLM

Montana Natural Heritage Program plant field guide

NatureServe

Navajo Natural Heritage Program (includes Navajo Endangered Species List, status, reports, abstracts, photos)

Nevada Rare Plant Atlas

New Mexico Natural Heritage Program - Botany

New Mexico Rare Plants

NRCS Publications Relating to Threatened, Endangered, and Rare Plants

Oregon Natural Heritage Information Center

Southwest Environmental Information Network (search engine that includes all AZ herbaria, and in some adjoining states including UT)

USDA Forest Service Celebrating Wildflowers: Rare Plants

USDA Forest Service Celebrating Wildflowers: Intermountain Region Rare Plant Profiles (critically imperiled plant profiles available as of July 2009)

USDI National Park Service Glen Canyon NRA Rare Plants

US Fish & Wildife Service Mountain Prairie Region

Utah Conservation Data Center (UDWFR)

Utah Division of Wildlife Resources Endemic and Rare Plants of Utah

Washington Natural Heritage Program Field Guide to Selected Rare Plants

Wyoming Rare Plant Field Guide