Galls on oaks

The photos on this webpage are taken from the most delightful Hainault Forest website. The text is largely from Oaks and Oakwoods by A.G Tansley, published in 1952. My thanks to both these sources in opening my eyes to the "funny things" growing on the oaks in my Plantation. A survey of my own 300 oaks planted in 2000/2002 indicates the galls found.

Where Galls come from

Oak apple Biorrhiza paillda See 22, 23, 24 and 33 The oak-apple...is formed by the gall-wasp...which pierces the terminal buds of the leafless twigs in January, laying numerous eggs...The eggs hatch at the beginning of May and on the emergence of the larvae begins to grow and completes its development about the end of the month...The wasps emerge in July...The fertilized female crawls down the tree, enters the soil and pierces young oak roots in which she lays her eggs. When these hatch into larvae, hard brown spherical galls up to half an inch in diameter are formed on the young root...In January the wasp is mature and bores through the hard wall of the root-gall, pushes through the overlying earth, crawls up the trunk of the leafless tree in search of suitable terminal buds... Currant gall Neuterus baccarum See 09 and 10 Formed on the male catkins when they appear in May. These are of the size, shape and colour of red currants, a bunch of which is closely imitated when an oak catkin is crowded with the galls. The wasps develop in them with great rapidity and most have emerged by the end of June. The summer galls may also be formed on the leaves, where they are larger and green, not red. The fertilized female wasp then attacks the lower surface of the leaves, causing the very common disc-shaped spangle galls to appear in July. These are of a beautiful red colour, at first with a central umbo, and sometimes cover the undersurface of the leaf very thickly, causing it to wither prematurely. In September the spangle gallsbecome detached, fall to the ground and round off, the contained larvae continuing to grow through the winter. The wasps appear in April and attack the catkins or leaves, producing the summer currant galls.

01 Acorn Gall Callirhytis Erythrocephala

02 Acorn Gall Callirhytis Erythrocephala

03 Gall on acorn cup Andricus Grossulariae

04 Artichoke Gall Andricus Fecundator 2008

05 Bud Gall Andricus Solitarius 2008

06 Cherry Gall Cynips Quercusfolii 2008

07 Cola Nut Gall Andricus Lignicola 2008

08 Cola Nut Gall Andricus Lignicola 2008

09 Common Spangle Gall Neuroterus Quercusbaccarum 2008

10 Currant Gall Andricus Quercusbaccarum

11 Distorted Leaf Gall Andricus Curvator

12 Ramshorn Gall Andricus Aries 2008

13 Catkin Gall Andricus Aprilinus

14 Gooseberry Gall Andricus Grossulariae

15 Hedgehog Gall Andricus Lucidus

16 Knopper Gall Andricus Quercuscalicis

17 Knopper Gall Andricus Quercuscalicis

18 Knopper Gall Andricus Quercuscalicis

19 Lateral Bud Gall Andricus Inflator

20 Sea Anemone Gall Neuroterus Saliens

21 Barnacle Gall Andricus Testacaipes

22 Oak Apple Biorhiza Pallida

23 Oak Apples Biorhiza Pallida

24 Oak Apple Biorhiza Pallida

25 Leaf vein lobe folded down Macrodryplosis Dryobia 2008

26 Tightupward roll between lobes Macrodiplosis Volvens

27 Oak Marble Gall Andricus Kollari

28 Oak Marble Gall Andricus Kollari

29 Oyster Gall Neuroterus Anthracinus

30 Ramshorn Gall Andricus Aries 2008

31 Ramshorn Gall Andricus Aries 2008

32 Gall on acorn cup Andricus Grossulariae

33 Root Gall Biorhiza Pallida

34 Sea Anemone Gall Neuroterus Saliens

35 Silk Button Gall Neuroterus Numismalis

36 Small Pea Gall Cynips Divisa

37 Small Pea Gall Cynips Divisa

38 Smooth Spangle Gall Neuroterus Albipes

39 Striped Pea Gall Cynips Longiventris

40 Swollen tip of twig Andricus Inflator

41 Truffle Gall Andricus Quercusradicis

42 Asterix Gall Andricus asterix

Compiled, formatted, hyperlinked, encoded, and copyright © 2006, John Palmer, All Rights Reserved.