598 



COMPARATIVE MORPHOLOGY OF FUNGI 



result of the swelling of their membranes, lie imbedded in a gelatinous 

 sheath. In Ustilago Tragopogonis-pratensis (Rawitscher, 1912) and in 

 U. Heu fieri (Sartoris, 1924), they divide into short unicellular sections 

 which become moniliform and loosen themselves from the cell chain. 

 They are irregularly angular (Fig. 397, 8 and 9), subsequently round off 

 and change to thick-walled spores whereby the dissolved membranes are 

 resorbed. In Entyloma Nymphaeae (Lutman, 1910) the sporogenous 

 hyphae form numerous short side-branches, each of which develops a 

 terminal spore (Fig. 394, 4 to 8). In Neovossia, at least in N. Moliniae, 

 the proximal part of the sporiferous branch becomes thickened and 

 remains as an appendage of the mature spores (Fig. 401, 3 to 5). In 



Fig. 394. — Entyloma Glauci. 1. Sorus of smut spores. Entyloma Nymphaeae. 

 2. Section of haustorium. The old appressorium has thickened its wall. 3. Young 

 appressorium with nuclei entering. 4 to 8. Development of smut spores. (1 X 500; 

 2, 4 to 8 X 1,600; 3 X 860; after Dangeard, 1892, and Lutman, 1910.) 



Cintractia, the spores are successively cut off from a columella-like stroma 

 which covers the ovary; they are progressively pushed outward and at 

 maturity increase very much in circumference, adhere more or less 

 securely and flatten into irregular polyhedra. In most forms the 

 mycelium is entirely used up by spore formation and dissolved by the 

 swelling; in Cintractia an unused part remains within the spore mass. 



The smut spores are hyaline and binucleate when young; in the course 

 of development the dicaryon fuses to a single diploid nucleus (Fig. 394, 

 4 to 8). The mature spore wall consists of a thin endospore and a brown 

 or violaceous, often characteristically sculptured exospore. In many 

 genera of the Ustilaginaceae, Sphacelotheca, Ustilago (Fig. 395) and 

 Cintractia (Fig. 397, 6) and of the Tilletiaceae, in Tilletia (Fig. 399), Neo- 



