British oak galls / by Edward T. Connold.

  • Edward Thomas Connold
Date:
1908
Catalogue details

Licence: In copyright

Credit: British oak galls / by Edward T. Connold. Source: Wellcome Collection.

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    The gall may be sessile and axillary upon the side of a stout branch or shoot, or it may be terminal upon a thin stem a few millimetres only in length, or securely affixed to a long slender twig. An example of the latter character, found by the author at Hastings in 1895, is of a globular specimen, 66 mm. in girth, situated terminally on a twig 88 cm. long, and not more than 8 mm. in diameter throughout its entire length. Normally the gall is globular. It is smooth all over, except at the pole opposite to that of attachment to the twig where it bears a small, sharp-pointed style (which is occasionally bifid), chocolate brown in colour. It consists of dead tissue, and is sometimes described as the pseudo-stigma, and the pseudo-carpel. It can be recognised during early development. When normal development of the gall is arrested early by parasites, or inquilines, the style is accentuated (Plate XXXVI, figs. 7, 8). Many oak-marbles gathered in winter and spring, have numerous small dark brown excrescences upon them which have pushed their way through the exterior of the gall. Hitherto these appear to have been known as brown bodies. In January, 1908, the author, believing them to be due to fungoid agency, sent specimens to the Royal Herbarium at Kew. They were there identified as being attacked by the fungus Phoma gcdlorum, Briard, a species for the first time recorded as occurring in Britain. See Plate XXXIX, div. A. The surface of the gall frequently has one or many small conical protuberances upon it (Plate XXXV), which vary much in size and height. There may be only one (figs. 17, 18), or as many as twelve or fifteen (fig. 7), all separate (figs. 10, 11), or coalescent in the form of a ridge (fig. 8), or ridges (fig. 5). For these conical elevations I propose the name of papillse. They are quite distinct in shape from the style. They arise gradually from
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