Irritating, that’s what it is—to plants!
Yes, many plants get downright irritated by bugs and bacteria, and they show it with some fascinating growths that botanists have chosen, aptly, to call galls (to “gall” means to irritate). Once you get attuned to what is normal for the appearance of particular plants, you soon begin to spot abnormalities. Most of the abnormalities that catch our attention are large-scale ones like diseases and infestations that kill the host plants—such as the spruce budworm infestation that is defoliating millions of acres of conifers in the Rocky Mountains.
Galls usually do not kill a plant, but they certainly add curiosities to many of our common trees and plants. The oak “apple” is one of the most common. I remember as a kid picking up those shiny, round, golf-ball size galls that collected under oak trees, but I didn’t have a clue about what they were or how they were formed. Later, as an adult, I found some horned galls on an oak that looked a lot like a miniature version of the spiked mace weapon of medieval times.
These unusual growths are caused by tiny wasps, mites, or smaller organisms that attach themselves to plants where cell division takes place and then irritate the plant in such a way that the cell division goes haywire—all for the benefit of the bug. Typically the abnormal growth that results provides habitat and/or food for the invading pest—often for larvae that live in it until they reach adulthood, when they exit and go on to start the cycle again.
What’s such a wonder to me is that while you’d think these growths would be ugly, shapeless blobs like the ash flower gall shown here, most of them have rather remarkable design and structure—almost as if the creature causing them desired an attractive home. What a great way to get a grand abode: Dig into a plant at just the right spot, cause an irritation that interrupts cell division, and have the plant’s own growth process provide your food and shelter.
I recently spotted the galls below in an area smaller than a football field across the street from our condo in land allowed to go natural. But to get a real visual treat, go to the Wikipedia article on galls and scroll down to the bottom to see a gallery of wonders. If you click on the links, you will see the amazing variety of galls that grow in oak trees around the world. [Click on the photos to see them larger.]
These natural curiosities reminded me of a thought expressed by George MacDonald, who was amazed at the magnificence of ice crystals at the edge of a puddle in the road. In his typical elegant fashion he wrote about the unexpected beauty of such natural oddities:
I wondered over again, for the hundredth time, what could be the principle which, in the wildest, most lawless, fantastically chaotic, apparently capricious work of nature, always kept it beautiful. The beauty of holiness must be at the heart of it somehow, I thought. Because our God is so free from stain, so loving, so unselfish, so good, so altogether what He wants us to be, so holy therefore all His works declare Him in beauty; His fingers can touch nothing but to mold it into loveliness; and even the play of His elements is in grace and tenderness of form.
See you outdoors!