126 Life Histories of \'arious Grass Smuts. 



(c) The Tolyposporium smut is readily recognised from the sac-like 

 yellowish membrane enveloping the spores (Plate XVIL). The spore-balls 

 are very black, and the spores are firmly and permanently united. They 

 germinate readily in water, even after being kept for four years, and produce 

 a promyceliura which bears lateral and terminal conidia. When the conidia 

 are detached they bud in a yeast-like manner. 



4. Wallaby Grass Smuts. 

 {a) Black Smut (Ustilago readeri, Syd.) 

 (b) Bronze Smut {Ustilago comburens , Ludw.) 



(rt) The black smut is fairly cc*mmon on various species of Danthonia or 

 Wallaby grass, and is found on the leaves as well as in the inflorescence. It 

 has been known for a considerable time, although only recently named by 

 Sydow, who recognised it as a new species. It had been previously named by 

 Cooke U. destruens, Schlecht. 



It is a very conspicuous smut, as the entire inflorescence is invaded by it. 

 The glumes may remain, enclosing the blackened mass, but even they are some- 

 times partially or entirely destroyed (Plate XVIII. ). In its early stages the 

 diseased inflorescence is enveloped by the leaf -sheaths, but these soon fall 

 away and expose the black powdery mass of spores. On the leaves and sheaths 

 it also forms conspicuous lines, and altogether it is so destructive that the 

 grass is completely wiped out in patches. 



Germination. 



The spores germinate very readily in water, either immediately on ma- 

 turity or some time after. At the end of two years, however, only an 

 occasional spore is capable of germination. They produce an elongated 

 promycelium bearing lateral and terminal conidia, but their subsequent 

 history was not followed. No doubt, these conidia produce a delicate germ- 

 tube, which penetrates the young seedling and thus causes infection. 



(b) The bronze smut is easily distinguished by its bronze-green colour, in 

 contrast to the other, which is black (Plate XIX.). It occurs in the upper 

 portion of the stem, as well as in the inflorescence, which it ultimately com- 

 pletely destroys. The spores are exceedingly numerous and very minute, 

 and, althou.h at first agglutinated together, they soon become powdery. 



Germination. 



This was not very successful. Fresh spores were placed in a Petri -dish 

 with water, and after nine days a few of them produced a one-septate pro- 

 mycelium, but there was no further development. 



