146 l'stilc7go. 



FaM. 2. TiLLETIACE.E Till. 



This family is named from the genus Tilletia, which comes next to 

 Ustilago in the number of species. The spores produce on germination a 

 short promycelium, which usually bears at its apex a cluster of elongated 

 conidia. There are nine genera recognised, and only four are represented in 

 Australia, viz. : — Tilletia, Entyloma, Urocystis, and Doassansia. Entyloma 

 and Doassansia are d'stinguished by the spores being imbedded in the 

 tissues. 



USTILAGO Pers. 



Vegetative mycelium spreading in the tissues of the host and soon 

 disappearing. 



Sori forming powdery, usually dark-coloured spore masses, on various 

 parts of the hosts. 



Spores single, small, produced irregularly in the interior of clustered 

 terminal branches of fertile hyphae, which soon entirely disappear through 

 gelatinization. 



Germination by a short septate promycelium, which produces conidia 

 both apically and laterally near the septa, or by a promycelium developing 

 directly into a mycelium. 



Conidia germinating in water, usually producing slender infection threads, 

 but in nutritive solutions multiplying indefinitely after the manner of yeasts. 



This genus contains the most species, and is the most important from an 

 economic point of view. It includes some of the most destructive parasites 

 of the cereals, and although it occurs on a great variety of hosts, the largest 

 number are found on the Graminese. The only other host-plants represented 

 here belong to the Cyperaceoe, Polygonace?e, and Portulacea?. 



Brefeld divides this genus into three sub-genera or groups, according to 

 the mode of germination, viz. : — Pro-ustilago, Hemi-ustilago, and Eu-ustilago ; 

 but since the germination is not known in f|uite a number of Australian 

 species this classification cannot be followed. 



Australian species, 18. 



A vena, Arrhenafherum. 

 1. Ustilago avenae (Pers.) Jen;. 



Jensen, Charb. Cereal, p. 4 (1889). 

 Brefeld, Unters. Gesammt., Mvk. V.. p. 54 (1883). 

 Brefeld, Unters. Gesammt. Mvk. XL, p. 23 (1895). 

 Sacc. Syll. IX., p. 283 (1891).^ 

 Ustilago perennans Rostr. 

 Sori in spikelets, attacking all parts of the flower, even the glumes and 

 awns, usually completely destroying the ears and transforming 

 them into a dark-brown spore mass, which l:)ecomes powdery, and 

 is eventually dissipated. 



Spores globose to subglobose, occasionally ellipsoid, pallid ta 

 olivaceous or olive brown, more lightly coloured on one side, finely 

 echinulate, 5|-6J /ii diam., or 7-8 x o-Q jf, occasionally reaching 

 an extreme length of 11 /' and a breadth of 7 /). 

 On Arena sativa L. — Oats. 



Common — wherever Oats are grown. 

 On Avena fatua L. — Wild Oats. 



Victoria — Dookie, Nov., 1908. Longerenong, Nov., 1908. 

 On Arrhenatheruni avenaceum Beaxiv.^ Avena elatior L.-— Oat ^rass. 

 Victoria ~ Longerenong, Nov., 1909 ^Gibson.) 



