I love when I know the exact word to describe something, whether that “something” is an emotion, a color, taste, or plant part. To help you feel more confident in the words of the botanical world, I’m starting this Botanical Alphabet series. It may or may not be published in exact alphabetical order.

gall: abnormal growth or mass of plant tissue; develops in response to wounds from insects, mites, bacterium, fungus, etc.

Goodness, gracious, great galls of fire. Or of pupating insects. Or bacterium. Whatever.

I think galls are so fascinating. They can be on stems, leaves, twigs, trunks, even on roots. Insect galls form as a defense response to an insect laying eggs inside the leaf or stem tissue. Generally, these galls themselves are harmless to the plants unless they occur in very large numbers on young plants. Galls caused by bacteria, fungus, or nematodes, however, are symptomatic of diseases that can severely reduce plant growth or even cause death.

I think that one of the more interesting galls I’ve come across is the pinecone willow gall (or willow pinecone gall) in the picture above. Like you might guess from the name, it’s a gall that occurs on willows and looks like a pinecone. These galls are caused by a midge named Rhabdophaga strobiloides. The female midge lays an egg in a terminal (tip) bud and the plant reacts to the chemicals secreted by the midge, and from the egg itself, by elongating, broadening and hardening the leaf bud tissue into the pinecone-like gall.

Have you seen any interesting galls lately?