•exliaustion of its substance. Of course^ tlie florets 

 are never developed wlien subjected to the attack 

 of "smut/^ The whole plant assumes a faded, 

 sickly appearance, even before the spores are fully 

 ripened. We would recommend our readers, if they 

 collect one of the infected flower-heads, to put it 

 into a box or paper by itself, for if placed in the 

 box with other specimens it will so sprinkle them 

 "with its black powder as to render them nearly 

 useless for microscopic examination : everywhere 

 the microscope will detect, where the unaided eye 

 failed to recognize a trace, the ubiquitous spores of 

 Ustilago receptacnlorum (plate Y. fig. 94). 



In the fenny districts of the eastern counties a 

 species of '^ smuf called Ustilago typlwidcs attacks 

 the stems of reeds, forming thick swollen patches 

 •of several inches in length (fig. 128), sometimes 

 occupying the whole space between two joints or 

 nodes, and lying beneath the sheath of the leaves. 

 The spores in this species are larger than in the 

 species which attacks the culms of grasses in a 

 similar manner (plate VI. fig. 129). 



There are not many features in the rest of the 

 species of this genus of sufficient interest to the 

 general reader or microscopist to render it advisable 

 to furnish any detailed account of them. We may, 

 however, note that in a species found on the leaves 

 of the common cock^s-foot grass the spores are large, 

 obovate, and rough, with minute granules (figs. 117, 

 118). This species is known botanically as Ustilago 



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