Germination of Tcleiitosporcs of Ustilaginecr. 97 



same time. The promycelium emerges through a small 

 round opening in the epispore, its length corresponding to 

 the size of the spore. On the upper, free, blunt end of 

 the promycelium from four to eight protuberances appear, 

 which elongate themselves into branches and become the 

 cylindrico-fusiform promycelial spores. After all the pro- 

 toplasm from the interior of the teleutospores has been 

 passed into the upper end of the promycelium and into the 

 developing promycelial spores, a septum is formed close to 

 its upper end. If the promycelium happen to be a very 

 long one, two or more septa occur. The promycelial 

 spores, while still attached to the promycelium, become 

 united in pairs by a bridge-like connection. This conjuga- 

 tion takes place at the bases of the promycelial spores, 

 and but rarely at their summits. One of the conjugated 

 spores then buds out a secondary spore, which in its turn 

 sometimes produces a tertiary ; sometimes all these may 

 be observed in a chain. If there be an odd spore on the 

 promycelium which has not conjugated, it does not bud. 



Conidia* — These are produced from a mycelial mesh 

 that exists for the most part just beneath the epidermal 

 structures, and is provided with very numerous botry- 

 form haustoriae (Plate VI. Fig. i). The conidiophores 

 emerge through the stomata, or between the epidermal 

 cells (Plate VIII. Fig. i). The conidia are borne almost 

 horizontally; they are from 11 to 15/i long, and consist of 

 subpyriform cells attached by their larger end. A thin 

 hyaline membrane encloses the granular protoplasm, in 

 which a small vacuole may be observed. When placed in 

 a damp atmosphere the vacuole enlarges and a germ-tube 

 is produced, generally from the larger end of the conidium ; 

 into this germ-tube the protoplasmic contents of the coni- 

 dium are received and passed onwards as it elongates 



* Woronin, loc. cii. 



11 



