Sorosporinin. 175 



SOROSPORIUM Eud. 



Sori in various parts of the host, forming dark-coloured dusty spore 

 masses. Spore-balls composed of numerous spores, often rather loosely 

 united and at maturity completely separating. 



Spores usually of a deep-brown colour. 



Germination similar to that of Ustilago. 



The spore-balls are temporary, and when the spores entirely separate, 

 as they often do, at maturity, the genus cannot be distinguished from Usti- 

 lago. In such a case it is necessary to examine young stages and see the 

 young spore-balls. It is not surprising, therefore, that several Sorosporiums 

 have been described as Ustilagos. On the other hand, this genus is some- 

 times mistaken for Thecaphora and Tolyposporium, in which the spore-balls 

 are permanent. The sori are often provided with a false membrane, and the 

 order of development of the spore-balls is centrifugal, the youngest being 

 at the centre. 



Australian species, 13. 



Aristida. 

 31. Sorosporium consanguineum Ell. and Ev. 



Ellis and Evcrhart, Journ. Mvc. III., p. 5G (1887). 

 Sacc. Syll. VII., p. 514 (1888). 



Ustilago aristidae Peck, Bull. Torr. Bot. Club, XII., p. 35 (1885). 



Sori in ovaries and entirely enclosed by glumes, but sometimes the 

 black mass shines through them. 



Spore-balls irregular, subspherical to elongated oblong, up to 

 130 f-i in length, at first firm but afterwards readily separating and 

 in old specimens becoming completely broken up. Spores mostly 

 polygonal, also subgiobose to ovoid, smooth, or very finelv echin- 

 ulate, yellowish-brown, but dark-brown in the mass, 7-10 /ii long, 

 but may occasionally reach a length of 13 //. 



On Aristida arenaria Gaud. 



New South Wales — Namoi Kiver, 1887 (National Herbarium). 

 On Aristida hehriana F, v. M. 



Victoria— Dookie, June, 1903 (Pye). 



New South Wales — Narromine (Turner). 

 On Aristida lepfopoda, Bentli. 



New South Wales — Liverpool Plains (Turner). 

 On Aristida raniosa R. Br. 



New South Wales — Narromine (Turner). 

 On Aristida vagans Cav. 



New South Wal-\s— Wingello, Man;li, 1900 (Maidtu). 



Coolabah, Dec., 1908 (Maiden). 

 On Aristida sp, 



Queensland — (Bailey). 

 In the specimens examined, every seed seemed to be affected. The spores 

 are generally smooth, but sometimes the epispore is finely echinulate. 



