Flowerpot's picture

Warts/discs/"blobs" on the underside of oak leaves

Observed: 10th November 2012 By: Flowerpot
Different "blobs" on underside of oak leaf
What are these?
More little blobs on another leaf
Description:

I've seen light-coloured, convex discs on the underside of fallen oak leaves for years, but never found out what they are. Can anyone enlighten me? The differently coloured/textured ones shown in the first two pictures were something that I hadn't seen before, so they particularly piqued my curiosity.

Identifications
Species interactions

No interactions present.

Comments

D.M.H.'s picture

Galls

A gall is an abnormal growth produced by a plant or other host under the influence of another organism usually a fungi(rusts) or by an invertebrate(sawfly,mite,gall-wasp) but also by virus or bacteria.
The gall provides both shelter and food for grubs in the case of invertebrates.
There are several types on your leaf the two you mentioned are the Silk button and Common spangle(flying saucer shape) both caused by species of Neuroterus gall-wasps.
Hope this has helped ;-)

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D.M.H.'s picture

Probably want to edit this to

Probably want to edit this to appear under invertebrate rather than the plant group. That will be why there is no other records showing for my suggested ID.

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All given ID's are subject to error/ommissions. Please seek independent verification before acting on ANY advice given. BE SAFE =)