Cintractia. 165 



the gelatinous base may be entirely spore-bearing, or there may be strands 

 of undifierentiated hyphae, between which the fertile hyphae produce masses 

 or pockets of spores. 



The characteristic features of Cintractia are the central columella of 

 plant tissue, the development of spores from the inside outwards, and the 

 firmly agglutinated spores. As might be anticipated, there are some cases 

 where it is difficult to say whether the species should be regarded as an Usti- 

 lago or a Cintractia, as in Ustilago avenae, for instance, where there are only 

 the powdery spores to separate it from Cintractia, but if the three characters 

 given above are observed, then the genus will be a very convenient one. 

 Australian species 11. 



Fimbristylis, 

 20. Cintractia axicola (Berk.) Cornu. 



Cornu, Ann. Sci. Nat. Bot. p. 279 (1883). 

 Cooke, Handb. Austr. Fung., p. 324 (1892). 

 Sacc. Syll. VII., p. 480 (1888). 



Ustilago axicola Berk., Ann. Nat. Hist., p. 200 (1852). 

 Ustilago fimbristi/Us Thuem., Bull. Torr. Bot. Club, VI., p. 95 

 (1875). 

 Sori usually at base of flower stalks, forming compact, black, roundish 

 swellings, at first covered with whitish false membrane, which soon 

 disappears, exposing the dark-coloured spore-masses. 



Spores yellowish-brown, globose to subglobose when seen flat ; 

 compressed laterally, and appearing oblong when seen edgewise ; 

 smooth, average 13-14 /( diam. or 13-17 x 8-14 /(, intermixed 

 with hyaline, short, thread-like filaments derived from the stroma. 



Sterile cells scattered among the spores, large, colourless, some- 

 times at least twice as large as the ordinary spores, and round^ or 

 irregular in shape, owing to undergoing gelatinization. 

 On Fimbristylis sp. 



Queensland — Brisbane Kiver (Bailey). 

 Victoria (Mrs. Martin). 

 Fimbristylis is a small grass-like sedge, and when growing on wet un- 

 drained land, the smut is very abundant in some seasons. This was made 

 the type of a new genus founded by Cornu and differs from Ustilago in the 

 formation of a stroma or compact mass of filaments, from the outside of which 

 hyphae project, in which spores are successively developed. 



Spore formation. — A section of the stalk shows the persistent mycelium 

 in the diseased portions composed of delicate colourless hyphae which become 

 aggregated into a dark-brown stroma around the medulla, and fibro-vas- 

 cular bundles. 



Arising from the stroma and directed outwardly are dark-brown strands 

 of hyphae, slender and long-jointed, with the fertile hyphae between form- 

 ing pockets or compartments of spores which are at first young and pale and 

 gradually become dark antl mature. The outer spores are at first held 

 together by the remains of the strands from the stroma, but on maturing 

 gradually separate. 



(Plate XXXVII.) 



