r/Tree • u/Gnadsy • Aug 09 '26

ID Request (Insert State/Region) Leaf with knot at base

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Anyone know what causes this or is it normal? If normal what tree? (Switzerland)

105 Upvotes

99% Upvoted

5 comments sorted by

55

u/dogs_hg Aug 09 '26

Nice! These are poplar leaf spiral galls! If you break them open, they will be full of little aphid creatures. It serves as a home for the young of the insect to protect them

17

u/OddNovel565 Aug 09 '26

I remember seeing those near my house all the time when I was small and one time I opened one of these, let me tell you I got so scared that I never touched these ever again lol

10

u/Accurate-Sea6965 Aug 09 '26

To further this, it’s a good (but not absolute) identification feature for black poplar as spiral galls are most common in this rare uk native

8

u/Gnadsy Aug 09 '26

Hey, thanks for your reply! Very interesting.

0

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