Field Guide to Plant Galls of California and Other Western States by Ronald A. Russo, Ron Russo
Oak apples, honeydew and ambrosia galls, witches’ brooms, and fasciationsall are types of plant galls, a commonly observed, yet little-understood botanical phenomenon. Often beautiful and bizarre, galls are growths of various shapes, sizes, and colors produced by host plants in response to invading organisms. This guide, a trove of natural history lore, explores this hidden realm, taking a fascinating look at the world of plant galls, the organisms that initiate them, their host plants, and their intricate behaviors. Focusing on native trees and shrubs, but also discussing several galls that occur on herbaceous and ornamental plants, it illuminates the complex interrelationship between botany and entomology and magnifies our awareness of plant communities in the West.
* Identifies more than 300 species of galls95 on oaks, 22 on members of the rose family, 60 desert species, and 35 species that are new to science
* Describes plant galls from coastal dunes, the high Sierra, the Great Basin, forests throughout the western states, and the Mojave and Sonoran deserts
* Includes information on host selection, growth and development, predator and parasite defense, and animal and human uses of galls
Ron Russo recently retired as Chief Naturalist with the East Bay Regional Park District in Oakland, California. Among his books are Hawaiian Reefs: A Natural History Guide, Pacific Coast Mammals, Mountain State Mammals, Pacific Coast Fish, and Pacific Intertidal Life.
Table of Contents
Acknowledgments and Preface ix Introduction 1 About This Guide 4 What Are Galls? 5 The Science of Gall Study 6 A Brief History of Galls 7 Where Galls Form 9 Gall Inducers at a Glance 10 Common Types of Galls 13 Seasonal Appearance and Growth Rate 19 Environmental Factors 20 Damage to Host Plants 22 Galls as Nutrient Sinks 25 The Gall Community 27 Parasite-inquiline Influence on Gall Shape 28 Gall-Inducer Defense 29 Honeydew and Bees, Yellow Jackets, and Ants 31 Insect Predators 33 Birds and Mammals 34 The Gall Inducers 37 Bacteria 38 Fungi 40 Mistletoes 45 Mites 47 Aphids and Adelgids 50 Psyllids 52 Moths 53 Beetles 56 Leaf-mining Flies 57 Tephritid Fruit Flies 58 Midges 60 Wasps 63 Gall Accounts 73 Tree Galls 75 Shrub Galls 217 Miscellaneous Galls 333 Native Plant Galls 333 Ornamental Plant Galls 339 Epilogue 342 Glossary 343 References 347 Index 363