264 BRITISH GALLS 



FIG. 



14. Pluricellular hair from interior of gall of E. macrochelus. («^.) 



13. Felt of hairs between the axils of the larger veins on the under 



surface of leaf of Acer psmdo-platanus, caused by Phyllocoftes 



acericola. (J.) 



PLATE XIV 



Fagus sylvatica. The dense mass of twigs on the trunk are said to 

 have arisen through the presence of a species of Eriophyes. 



PLATE XV 



Leaves of Achillea millefolium, with galls caused by the presence of 

 Tylenchus millefolii. (f.) 



PLATE XVI 



1. Stems of Veronicae Chamaedrys, with tumours resulting from the pre- 



sence of Sorosphaera veronicae. (J.) 



2. Stem of Urtica dioica, with gall caused by Aecidium urticae, the aecidiaJ 



stage of Puccinia caricis. (J.) 



3. Stems of Holcus mollis, galled by Epichloe typhina. (^.) 



4. Stems o{ Alnus glutinosa, galled by Frankiella alni. (J.) 



5. Section of a mass of tubercles. (}.) 



PLATE XVII 



Branch (dead) of Abies pectinata, with swelling bearing a "witch's 

 broom, ' ' caused by the presence of the aecidial stage (Peridermium 

 elatiiium) of Melampsora cerastii. 



PLATE XVIII 



Part of frond of Pteris aquilina, with the margins of the pinnules in- 

 curved and thickened through the presence of the larvae of 

 Perrisia filicina. 



PLATE XIX 



Branch oljuniperus communis, with gouty swelling consequent upon 

 the attack of Gymnosporangium clavariaeforme. The bodies con- 

 taining the teleutospores ot the fungus are growing upon the 

 bypertrophied part of the stem. 



PLATE XX 



Betula alba, with numerous " witches' brooms " caused by Eriophyes 

 rudis. 



PLATE XXI 



1. Shoot of Prunus spinosa, with leaves galled by Eriophyes similis. (J.) 



2. Leaves of Alnus glutinosa, with galls caused by the presence of 



Eriophyes laevis. (J.) 



3. Section of gall of E. laevis. (f .) 



