I just splurged on the online purchase of an out-of-print book from an independent used bookstore. You see, I became obsessed with a particular field guide once I started more closely observing the many galls abundant in my area.
the gall that started it all–California Gall Wasp
Our native oaks are abundant hosts to an amazing variety of galls—they host more gall insects than any other native tree or plant in the western United States. Looking into an oak tree in California, it might be easy to mistake some of the types for fruit—the variety produced by the California gall wasp are often referred to as “oak apples,” though I wouldn’t take a bite out of one.
Galls can be considered a nursery for insect larva that the tree is forced to produce in response to the activity of the larva—chemical secretions produced by the larva after emerging from their egg causes the host plant to produce material that eventually forms the gall specific to that plant and insect combination.
There is nothing I (or anyone really) can write about galls that hasn’t been better and more exhaustively covered by Ron Russo; the article I linked above gives just a taste (here it is in its original publication).
His extensive and renowned guide on the topic is now “out of print” at UC Press but available at some online sites for a bit of an investment (a hard cover copy is available for just over $1,000). Hence my obsession. I managed to find a used paperback (for much less that the price of the hardcover I mentioned) that is in remarkable shape.
Field guides are a treasure—the cumulation of dedicated research and observation by an enthusiastic, committed individual (or team). The thrill of a well-researched, well-written, well-documented and well-illustrated field guide is difficult to explain to someone who isn’t inclined to the natural world.
This 340-page tome by Mr. Russo is no exception—a thorough and beautiful guide to the amazing diversity and variety of plant galls in California (and other western states). He worked as a naturalist for the East Bay Regional Park District for 37 years, retiring as the chief naturalist in 2003. He has discovered over sixty-five new species of gall-inducing organisms (including bacteria, fungi, aphids, moths, midges, and wasps).
In most instances, such a collection of concentrated knowledge on a narrow subject would be considered an obsession…well, actually, often the best field guides are indeed an obsession—so be it!
As “social progress” seems to favor the extremes of general, homogenized, mass media or niche, targeted, “tribal,” self-interested content, I’m more content to regularly connect with in-depth, specialized material, especially those intended for sharing knowledge. True field guides often represent years and years of study, research and careful compilation. Much to enjoy.
Take a few moments to find something like this in an area that interests you…
 Oaks of California by Bruce M. Pavlik, Pamela C. Muick, Sharon G. Johnson, and Marjorie Popper; Cachuma Press.