Sites that I have found to be especially useful to help identify plants for my own Wildflowers of Tucson, Arizona and The Firefly Forest - Arizona Wild Plants websites.
General information about Tucson wildflower seasons and/or current wildflower sightings:
Arizona-Sonora Desert Museum - 2006-2007 Desert Wildflower Bloom Forecast - (Current wildflower sightings)
Arizona-Sonora Desert Museum - Flowering Seasons in the Sonoran Desert
Saguaro Juniper Corporation - Sonoran Desert Plants: Seasonal Flowering Schedules
Photographs and/or drawings of Tucson, Arizona or Southwest wildflowers:
Arizona Game & Fish Department - Plant Abstracts, Distribution Maps & Illustrations
Arizona-Sonora Desert Museum - Biological Survey of Ironwood Forest National Monument - Flora Image Gallery
Arizona-Sonora Desert Museum - Flowering Plants of the Sonoran Desert
Arizonensis - Sonoran Desert Naturalist - Exploring The Sonoran Desert - A guide to the Flora and Fauna
Cabeza Prieta Natural History Association - Plants of the Sonoran Desert
Casas Arroyo H. A. - The Flora (and Some Fauna) of Casas Arroyo, Sonoita, AZ
Chris Trask: Homepage - Sonoran Desert Wildflowers
Delange.org - Arizona Wild Flowers, Wildflower Pictures And Photos
DesertUSA - Wildflower Field Guide
Erik Enderson Photography
Flora of the NMSU Range & Livestock Research Center (Corona Ranch)
Glendale Community College - Arizona Plants Image Gallery
Michael Moore - SW School of Botanical Medicine
Mineralarts - Southern Arizona Rare Cactus Photos
Naturesongs - Common Plants of the Verde Valley & Sedona
NAZ Flora - Plants represented in images (Northern Arizona Plant Photos)
New Mexico Flora - Images of plants from the southwestern U.S.
New Mexico Rare Plants - Photographs of New Mexico's Rare Plants
New Mexico State University - Medicinal Plants of the Southwest
Pima Community College - Desert Ecology of Tucson, AZ - Common Desert Plants Around Tucson
RimJournal - Wildflowers of the Southwest deserts
Saguaro Juniper Corporation - Our Lands and their creatures - Information/Images
Sevilleta National Wildlife Refuge Field Guide to Flowers (~ 6.7 MB pdf)
Southwest Colorado Wildflowers
Southwest Environmental Information Network - SEINet Collections Search
Southwest Environmental Information Network - SEINet Image Library
Todd's Desert Hiking Guide - Flora and Fauna
Tucson Cactus and Succulent Society - TCSS Guide to Tucson Area Succulents
The University of Arizona - Arizona Flora and Fauna Image Gallery
The University of Arizona Photo Library (ACIS) - Weed Photo Gallery
The University of Arizona Press - An Illustrated Guide to Arizona Weeds
Vanderbilt University - Bioimages - Arizona Plants
Western New Mexico University - Vascular Plants of the Gila Wilderness
Whitethorn House - Southwestern Cacti
Whitethorn House - Wildflowers of the Tucson Mountains
Photographs and/or drawings of western or U.S wildflowers:
Amherst College - Project Lycieae - North America Grabowskia and Lycium Species (Desert-thorn or Wolfberry plants)
The Bugwood Network and USDA Forest Service - Forestry Images
California Department of Food and Agriculture - Encycloweedia
California Lutheran University - Wildflowers of Southern California
CalPhotos: Plants
Digital Flora of Texas - Vascular Plant Image Library
Eastern Colorado Wildflowers
eNature.com - The Lady Bird Johnson Wildflower Center - Native Plant Guide
Fall-Blooming Plants of the East Mojave
The Lady Bird Johnson Wildflower Center - Native Plant Information Network - Image Gallery
The Noble Foundation - Plant Image Gallery
RangeNet.org - Photo Album of Western Plants
Reny's Wildflowers - Photos of wildflowers, native plants, shrubs, trees, habitats, landscapes
Southern California Wildflowers
Trees of Southern California
UMass Extension Weed Herbarium
University of California Davis - Astragalus homepage
University of Maryland - An Array of Botanical Images by James L. Reveal
University of Texas at El Paso - Chihuahuan Desert Plants
USDA Forest Service - Celebrating Wildflowers
USDA - Plants National Database
Wildflowers and Weeds - Plant Families Photo Gallery: Wild Flower Identification Tools
Photographs and/or drawings of Mexican wildflowers (flores silvestres)*:
Malezas de México - Weeds of Mexico
Flora en el Estado de México (Flora in the central Mexican state of Mexico)
* If you know of any other Mexican wildflower or plants websites, please let me know!
Detailed plant information:
Harvard University - Flora Online - Flora of North America
Jepson Flora Project: Index to California Plant Names - Index to Treatments From The Jepson Manual
Plants For A Future - 7000 useful plants
USDA Forest Service - Fire Effects Information - Plant Species Life Form
USDA - Plants National Database - Plant Guides and Fact Sheets
Plant Checklists or surveys for the Tucson area:
NPS - Subplot field cover for 10x10 meter vegetation monitoring plots in Rincon and Tucson Mountain Districts, Saguaro National Park, Arizona
Pima County, Arizona - Sonoran Desert Conservation Plan - Pima County Plant Listing
SDFS Arizona Data Services Program - Floristic surveys of Saguaro National Park Protected Natural Areas - TECHRPT68.pdf - 580 KB
University of Arizona Herbarium - ARIZ - Roskruge Mountains - Roskruge Plant List
University of Arizona Herbarium - Checklist for the Plants of the West Branch of the Santa Cruz - Kathryn Mauz, 2004
University of Arizona Herbarium - ARIZ - Tucson Mountains - UA Herbarium Tucson Mountains List by Family - (A - C) - (D - F) - (G - R) - (S - Z)
Plant checklists for Arizona:
Arizona Plants Checklist - 488 KB Text File
Southwest Environmental Information Network - Symbiota - Identification Keys and Checklists
USDA - Plants National Database - State PLANTS Checklist
Tucson wildflower seeds:
Native Seeds/SEARCH - Wildflower
Search all of the above websites:
