Weird galls

Has an alder tree ever poked its tongue out at you? If yes, then it's likely you've spotted an alder tongue gall! These are caused by a fungus called Taphrina alni, which infects the scales of female alder catkins, creating these mischievous looking tongue-like growths.

A tiny wasp called Andricus kollari produces brown, marble-shaped growths on oak twigs. Inside the gall, the wasp larvae feed on the tissues but cause little damage. They make a little hole and leave as an adult in autumn. In the past, these galls have been used to make dyes and ink!

A knobbly looking growth that develops on acorns, caused by the wasp Andricus quercuscalicis. Galled acorns fall from oak trees in late summer. The adult wasps normally come out the following spring, but some can stay in their galls for up to four years!

A red, hairy growth that can be seen on wild roses throughout the year (though it turns brown in winter). It is caused by a tiny gall wasp that lays its eggs in a bud in the spring. The wasp larvae live inside and emerge as adults the following spring.

Caused by the very well-named gall wasp Andricus aries (the star-sign Aries is represented by an image of a ram), this gall can be found on oak trees and often has two yellowish horns, which later turn brown. Andricus aries was first discovered in Britain in 1997!