FUNGOID PESTS OF CULTIVATED PLANTS. 217 



the tips of the threads, somewhat narrowly club-shaped, with one trans- 

 verse division near the centre (30-50 x 5-7 u}. 



Known also in France, Germany, Belgium, and Italy. 



Sacc. SylL iv. 1640; Sacc. Filial, t. 788 ; Cooke, Hdbk. No. 1748. 



ALDER DISEASE. 

 Valsa oxystoma. 



Found on all diseased Alder-trees in Pomerania. 

 Journ. E.H.S. xxix. 1905, p. 739. 



ALDER-LEAF BLISTER. 

 Taphrina Sadebeckii (Joh.). 



The fungus causing this disease was at first called Ascomyces Tos- 

 quinetii, but that name has now been abandoned for the above. 



It produces blisters on the upper surface of the leaves of the Alder, and 

 the naked asci or spore-sacs produce a hoary appearance. These asci are 

 truncate, or abrupt, at each end (41-55 x 15 /x,), and contain eight spherical 

 sporidia, which are colourless (5-6J /u diam.). 



Known in Germany, Belgium, and Sweden, as well as in Britain. 

 Sometimes called Exoascus flavus. 



Sacc. SylL viii. 3338 ; Phil. Br. Dis. p. 403 ; Grevillea, vi. p. 25 ; 

 Mass. PL Dis. p. 91 ; Hart. & Som. Dis. Trees, p. 133. 



ALDER CATKIN BLISTER. 

 Exoascus alnitorquus (Tul.). 



This species attacks the female catkins of the Alder, which are thereby 

 much deformed. It occurs also sometimes on the leaves, which become 

 yellowish and primrose, blistered and contorted. The asci, or spore-sacs, 

 are clavate (3 1-37 x 6-7 /i), with a basal cell attenuated downwards until 

 it becomes acute (11-20 x 6-7 p). The globose sporidia are small 

 (3-5 fj. diam.) and numerous. 



Known also in France, Belgium, Germany, Sweden, and North 

 America. 



Sacc. SylL viii. 3345 ; Phil. Br. Disc. p. 403 ; Grevillea, v. p. 62 ; 

 Hart. & Som. Dis. Trees, p. 133, fig. 72. 



ALDER-ROOT TUBERCLES. 

 Plasmodiophora Alni (Wor.). 



This disease of Alder roots was first-called Schinzia Alni, but it does 

 not appear to differ greatly from the club-root of Crucifers. The roots 

 become swollen and deformed, exhibiting a mass of small tubercles as 

 large as the seed of a Vetch, or sometimes larger, and 2-10 cm. diam., 

 which tubercles contain numerous globose spores aggregated in clusters 

 or bunches (8 p. diam.) and of a mucous consistency when cut. 



Known in Germany, Poland, and Italy 



Sacc. SylL vii. 1569; Gard. Chron. Oct. 6, 1894, p. 398; Hart. & 

 Som. Dis. Trees, p. 39. 



