BRITISH GALLS 
158 
Acari 
Fungi 
Diptera 
Hemispherical pustules (3 mm. high) on the upper 
surface of the leaf, always at the junction of the lateral 
veins and midrib. Yellowish-green, 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 Fee. 
Eriophyes Nalepai Focken 206 
Connold, Veg. Calls, pi. 48 ; Plant Galls, fig. 22. 
Houard, No. 1132. 
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 ahiitorquus 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 
wound surrounded by a thickened irregular mass of 
living bark, commonly known as “ canker.” 
208 a 
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 or 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, forming 
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.) Rene Maire 210 
Syn. Schinzia alni Woronin, Plasmodiophora alni Wor., 
Frankia subtilis Brunchorst. 
Connold, Plant Galls, frontispiece and fig. 20. 
Carpinus Betulus Linn. 37. Hornbeam. 
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 
