108 FUNGOID PESTS OF CULTIVATED PLANTS. 



branched and creeping, with erect fertile branches, the ultimate branches 

 ■ are produced in whorls of four, bearing clusters of conidia. The conidia 

 themselves are nearly globose, produced in chains, and at first gelatinous 

 (5-6 fj diam.). 



Of course the Mushrooms are destroyed, with no chance of recovery. 

 The house should thereafter be thoroughly cleansed before use for the 

 same purpose again. 



Grcvillea, xvii. p. 80. 



Invading Agarics. 



Agarics, other than the Mushroom, sometimes invade Mushroom 

 beds as unwelcome usurpers. Of these are Clitocybe dcalbata, Hcbcloma 

 fastibile, and others. 



Gard. Chron. Sept. 9, 1893, p. 299. 



Mushroom Mould. 



Mycogone alba (Letell.), PI. IX. fig. 138. 



This mould overspreads all parts of cultivated Mushrooms, and may 

 possibly be the same as that which thickens and distorts the gills, and 

 spoils a whole bed of Mushrooms just as it is arriving at maturity. It 

 spreads thinly over the surface, which the mycelium penetrates and 

 distorts like a whitish bloom. The very short branches bear at their 

 apex rather large obovate conidia divided into two cells, of which the 

 upper is much the larger, and almost globose, except where it is flattened 

 by junction with the lower cell (30 x 20 /j). The surface of the upper 

 cell appears to be somewhat rough, but not distinctly warted. 



Very probably this is the early, or conidiiferous, condition of some 

 species of Hypomyces, a genus of parasitic Sphceriaccce. 



Grcvillea, xvii. p. 80 ; Letell. Champ, t. 6G7, f. 2 ; Gard. Chron. 

 Sept. 9, 1893, p. 299 ; Mass. PI. Dis. 133. 



Mushroom Bed Sclerotium. 

 Xylaria vaporaria (Curr.). 



The presence of sclerotia in mushroom beds was observed by Curry 

 many years ago. In 1862 he planted some in damp sand and induced 

 germination. Since that time they have been found perfecting themselves 

 naturally. 



The sclerotia are irregular, corky, rough, and black. They produce 

 simple or branched stems, sometimes several inches in length, reaching 

 to the surface of the soil. The tips of the stems are expanded into a 

 somewhat conical head, in the lower part of which the perithecia are 

 immersed, while the upper portion is barren and of a light brown colour, 

 the lower half darker. The contents of the perithecia consist of long, 

 cylindrical, transparent cells, or asci, each of which encloses eight dark 

 brown sporidia, of an almond shape (40-50 fi long). 



It is not unusual to meet with these sclerotia in Mushroom beds 

 occasionally producing these stems, and sometimes only the thickened, club- 



