444 
Williamson.—The Origin of ‘ Golden ’ Oak. 
List of References. 
1. Coons, G. H.: Factors involved in Growth and Pycnidium Formation. Journ. Agric. Research, 
v. 7 I 3 > I9 i( 5. 
2. Groom, P. : ‘ Brown ’ Oak and its Origin. Annals of Botany, xxix. 393, 1915. 
3 . Hedgecock, G. G. : Studies upon some Chromogenic Fungi which discolour Wood. Missouri 
Bot. Gard. Report, xvii. 59, 1906. 
4. Horne, A. S., and Williamson, H. S. : The Morphology and Physiology of the Genus Eidamia. 
Annals of Botany, xxxvii. 393, 1923. 
5. Hubert, E. E.: A Staining Method of Hyphae of Wood-inhabiting Fungi. Phytopathology, 
xii. 440, 1922. 
6. Larbaud, Mile: Nouvelle technique pour les inclusions et les preparations microscopiques des 
tissus vegetaux et animaux. Comptes Rendus, xxi. 1317, 1921. 
7 . Wehmer, C.: (1) Zur Morphologie und Entwickelungsgeschichte des Penicillium luteum Zuk., 
eines iiberaus haufigen griinen Schimmelpilzes. Ber. d. deut. Bot. Ges., xi, 499, 1893. 
7 a. -- : (2) Die Arten der Gattung Penicillium. Lafar’s Handbuch der Techn. Mykol., 
iv. 227, 1907. 
8. Williamson, H. S. : A New Method of Preparing Sections of Hard Vegetable Structures. 
Annals of Botany, xxxv. 139, 1921. 
EXPLANATION OF FIGURES IN PLATE X. 
Illustrating Mrs. Williamson’s paper on the Origin of ‘ Golden’ Oak. 
Fig. 1. Transverse section of Quercus robitr infected with Eidamia catenulata, showing 
islands of cells filled with a yellow or tangerine coloured, somewhat refractive substance. The large 
vessel also shows some of the same substance lining the wall. 
Fig. 2. Tangential section of Quercus robur showing hyphae of E. catenulata running longitu¬ 
dinally and passing through pits in the cell-walls. 
Fig. 3 - Tangential section of Quercus robur showing excreted globules on the hyphae of the 
fungus. One wood parenchyma cell is full of this substance and shows remains of disorganizing 
hyphae. 
