158 



BRITISH GALLS 



Aeari Hemispherical pustules (3 mm. high) on the upper 



surface of the leaf, always at the junction of the lateral 

 veins and midrib. Yellowish-gjreen, becoming red and 

 brownish. Each pustule contains a cavity with a wide 

 opening on the lower surface of the leaf. It is lined with 

 hairs that are either white or. a clear yellowish-brown. 

 When the galls are very numerous the margins of the 

 leaf are deflected. Erineum axillare F6e. 



Eriophyes Nalepai Focken 206 

 Connold, Veg. Galls, pi. 48 ; Plant Galls, fig. 22. 

 Houard, No. 11 32. 



Fungi Pistillate catkins deformed, producing long tongue-like 



greenish or reddish outgrowths, which are either straight or 

 curled, attaining 30 mm. in length. Solitary or gregarious, 

 sometimes ten on one catkin. June to October. The 

 same fungus also produces blisters on the upper surface 

 of the leaves. (Text, Fig. 33.) 



ExoAscus ALNiTORQUUS Winter 207 

 Syn. Ascomyces alnitorquus Massee. 208 



Connold, Plant Galls, fig. 25. Swanton, Fungi and 

 how to Know Them, pi. 14, fig. 6. 



Branches swollen, bark destroyed, the margin of the 

 >i wound surrounded by a thickened irregular mass of 

 . living bark, commonly known as " canker." 



208a 

 Massee, Textbook of Plant Diseases, p. 127. 

 At one time supposed to have been caused by the fungus 

 Nectria ditissima, which, however, is a saprophyte. Prob- 

 ably of bacterial origin. 



Small white ox yellowish blisters usually on the under 

 surface of the leaves ; less frequently on the upper surface. 



Taphrina Sadebeckii Johans. 209 

 Massee, Textbook of Plant Diseases, p. 91. 



,, Clusters of abnormal thickened tubercles, fonning 



nodular spherical masses varying in size from a pea to 

 a walnut. Sometimes occurring at the base of the stem. 

 Reddish-brown or yellowish. I. to XII. (Plate XVI. 4.) 



Frankiella alni (Wor.) Ren6 Maire 210 

 Syn. Schimia alni'Woxoma, Plasmodiophora alniVfor., 

 Frankia subtilis Brunchorst. 

 Connold, Plant Galls, frontispiece and fig. 20. 



Carpinus Betulus Linn. 37. Hornbeam. 

 Diptera The midrib is swollen on the upper surface of the leaf 

 between two lateral veins, of which the bases are also 

 swollen. The gall contains two cavities, each with a single 



