21-2 



ASCOMYC 'ETES. 



abjointed (Fig. 103); in the interior of the spots are produced 

 tiiiy conidia (Lcptostroma larieimiw), incapable of germination. 



FIG. 101. Tuft of larch needles, the greater number of which are more or less 

 attacked by Spkaerella iaricina. (After R. Hartig.) 



The rod-shaped conidia infect particularly the lower needles of 

 the crown, and three weeks thereafter new conidial cushions 





Fie. 102. Sp/'i'.i ''// laricina. Section through a diseased spot on a larch 

 needle. The interior of the leaf is permeated with the intercellular mycelium. 

 Two conidial cushions are shown ; from these numerous long rod-shaped conidia 

 are given off externally (those of the upper cushion have nearly all been carried 

 off by rain), while cavities inside the cushions are filled with micro-conidia. 

 < J-ffi. (After R. Ilartig.) 



appear. Their distribution and germination are facilitated by 

 wet weather. The perithecia (Fig. 104) are matured towards 



