TG3203 : Oak galls (caused by Andricus grossulariae)

taken 7 months ago, near to Rockland st Mary, Norfolk, Great Britain

Oak galls (caused by Andricus grossulariae)
Oak galls (caused by Andricus grossulariae)
Andricus grossulariae is a gall wasp of the Cynipidae family and causes two types of gall on oak trees. In spring, galls are caused by the sexual generation. These galls only grow to about 10mm and are shaped like pointed peas > LinkExternal link. In late summer and autumn, a second generation of galls, formed on the acorn cups of Pedunculate and Sessile oaks, contains the asexual grubs. These very different looking galls (depicted here) are much larger and quite contorted in shape. In both cases the galls first appear pink in colour and as they mature they turn red, then green and finally brown. Arrived in Britain around the year 2000 and now spreading northwards.
Plant galls
Galls are abnormal growths, swellings, pustules or discolourations produced by a plant or other host under the influence of another organism, involving the enlargement and/or proliferation of host cells and the provision of both shelter and food or nutrients for the invading organism. Galls provide a home for the larvae or grubs of certain invertebrates, where they can feed and develop, and each type of gall-producer or causer is specific to a particular kind of plant. Galls come in many shapes including spheres, knobs, lumps, warts or blisters, each being characteristic of the causal organism, and can have a range of colours. Galls can be found on the stems, leaves, flowers, fruits, seeds and roots of plants. Although many varieties of plants can be affected, oaks and willows are particularly rich in galls. Oaks are said to be host to more than 500 different types of galls. Weather, plant susceptibility, and pest populations affect the occurrence of plant galls.

Certain galls are documented to have been used in the production of ink since at least the time of the Roman Empire, and iron gall ink was the main medium used for writing in the Western World from the Middle Ages to the early 20th century. In Chinese medicine, oak galls are used as a remedy called moshizi, which is used for treating dysentery, ulcers and hemorrhoids among other things. Native Americans used poultices of ground gall nuts on sores, cuts and burns. The high content of tannic acid also makes oak galls a good source for tanning and dyeing.

Galls cause little permanent injury and rarely kill the infested plant.

For more detailed information go to the British Plant Gall Society's website at LinkExternal link
Creative Commons Licence [Some Rights Reserved]   © Copyright Evelyn Simak and licensed for reuse under this Creative Commons Licence.
1:50,000 Modern Day Landranger(TM) Map © Crown Copyright
1:50,000 Modern Day Landranger(TM) Map © Crown Copyright
TIP: Click the map for Large scale mapping
Change to interactive Map >
Grid Square
TG3203, 556 images   (more nearby )
  (find more nearby)
Date Taken
Tuesday, 22 August, 2017   (more nearby)
Tuesday, 22 August, 2017
Geographical Context
Wild Animals, Plants and Mushrooms 
Subject Location
OSGB36: geotagged! TG 3228 0395 [10m precision]
WGS84: 52:35.0221N 1:25.6368E
Camera Location
OSGB36: geotagged! TG 3228 0393
View Direction
NORTH (about 0 degrees)
Looking for a postcode? Try this pageExternal link
Clickable map

Image Type (about): close look 
This page has been viewed about 21 times.
View this location: KML (Google Earth) · Google MapsExternal link · Bing MapsExternal link · OS Map Checksheet · Geograph Map · geotagged! More Links for this image
W Go E
You are not logged in login | register