On my hike up Kennedy Ridge this morning the most colorful thing I saw by a longshot:
Some folks call them oak apples. Us science types call them galls. What is a gall and why do they look so tasty.
A gall is an abnormal growth which can be found on almost any part of a plant, though the leaves are especially popular. The are generally the work of immature insects, though galls can also be caused by fungi or even other plants (like mistletoe).
They are basically “plant tumors”, though unlike human tumors they generally do not harm the host plant, just make it a little ugly temporarily.
There are over 1500 species of gall producers though around here the most common are midges, aphids and wasps.
Basically these species create the gall for the purposes of food or shelter for themselves or for their young. Galls can vary in shape and size from a simple wart on a manzanita leaf to a gnarly spiked ball on a ceanothus to the cue ball sized oak gall.
Each species is very picky about what plant they start their galls on. In our area the most popular hosts are oaks, willows, ceanothus and members of the aster family.
Interestingly, some galls are useful to human culture. The Cynips gallae-tinctoriae has been used as a source of ink. These galls contain 50 to 65 percent tannic acid and are very useful as ink or in dyes for wool. The Greeks used the Cynips theophrastea gall for lamp fuel. Honeydew producing galls are used to attract bees and flies in the agricultural industry. Some galls have been known to be used for food and medicine.
And if you can’t get enough gall there’s even a book devoted to it: http://www.amazon.com/California-Western-States-Natural-History/dp/0520248864/ref=sr_1_2?s=books&ie=UTF8&qid=1383926569&sr=1-2&keywords=galls
Thanks for reading everyone, have a great weekend.