Spring Wildflowers at Henry Coe State Park, Barry Breckling. My primary source for wildflower identification. You can order this online or stop into the Rangers Office at the park. You can also order or pick up a copy of the glossy, full-color brochure Wildflowers of Henry W. Coe State Park.
There's a Guide to Wildflowers of Almaden Quicksilver County Park available by contacting Kitty Monahan. Once Casa Grande reopens to the public, you'll be able to buy copies in its gift shop. Additional wildflower identification resources include Peterson Field Guides, Pacific States Wildflowers.
My two primary sources for butterflies: Kaufman Field Guide to Butterflies of North America, Jim P. Brock & Kenn Kaufman and Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions, Arthur M. Shapiro and Timothy D. Manolis. I message Art Shapiro for butterfly ID. He responds in 24 hrs. Buy his book!
I use two compact, carry-along guides to butterflies and birds: Local Butterflies of the San Francisco Bay Area and Local Birds of the San Francisco Bay Area. These guides can be bought online or at local book stores.
Indispensible, is a copy of National Wildlife Federation Field Guide to Insects and Spiders of North America. Guide includes butterflies, dragonflies, moths, backyard bugs, water bugs, bugs found on trees and along trails.
For dragonflies, my primary source is Dragonflies of California and Common Dragonflies of the Southwest, A Beginner's Pocket Guide, Kathy Biggs.
National Audubon Society Pocket Guide: Familiar Butterflies of North America is a nice edition to any library.
Please feel free to message me, Cait Hutnik with questions or to recommend additions to this list.