228 



THE FUNGI WHICH CAUSE PLANT DISEASE 



Trichosphaeria Fuckel (p. 226) 



Perithecia usually free, globose, woody or carbonous, hairy, 

 ostiole flat or papillate; asci-cylindric, 8-spored; spores 1 to 2-celled, 

 hyaline; paraphyses present. 



There are some forty species, mainly saprophytes. 



T. sacchari Mass.^"- ^^ 



Perithecia broadly ovate, dark-brown, beset with brown hairs; 

 spores elongate-ellipsoid, 1-celled; the conidial forms are various 



Fig. 162. — ^Trichosphseria. E, habit sketch; G, conidial 

 stage. After Lindau, Winter and Brefeld. 



and their genetic connection is by no means certain. (1) (=Conio- 

 thyrium megalospora) Pycnidia 1-3, on a dark-colored, parenchy- 

 matous stroma; conidia elongate, straight or curved, brownish, 

 12 X 5 Ai, (2) The macroconidia (=Thielaviopsis ethaceticus) 

 see p. 596, are often found forming intensely black, velvety 

 layers lining cracks and cavities in diseased canes. (3) Micro- 

 conidia produced on the surface in Oidium-like chains. Their 

 connection with this fimgus is disputed and uncertain.*^ 

 It is a sugar cane parasite. 



