Ciniractia. 173 



Androjwgon. 



29, Cintractia sorghi-vulgaris (Tul.) Clint. 



Clinton, liuU. 111. Agr. Exp. 8ta. No. 47 (1897). 

 Sacc. Syll. VII., p. 4.5G (1888). 



Sponsorium sorghi Link (182.j). 

 Tilletia sorghi-vulgaris Tul. (1847). 

 Ustilago sorghi (Link) Pass. (1873). 

 Ustilago tulasnei Kuehn (1874). 

 Sphacelotheca sorghi (Link) Clint. (1902). 



Sori generally in the ovaries, occasionally in the stamens, forming oval 

 to oblong or cylindrical projecting bodies up to 6 mm. in length, 

 at first protected by a fungus membrane which ultimately ruptures 

 at the top, allowing the escape of the dark -brown spore mass and 

 exposing the distinct columella composed of plant tissues. 



The fungus membrane is composed of hyaline, subglobose to 

 oblong cells, on an average 9-13 f.t long. 



Spores more or less agglutinated, globose to subglobose or occa- 

 sionally shortly elliptical, dark-brown in the mass but brownish- 

 olive individually, smooth, average 6 ft diam. and varying from 

 5"5 to 7 /<. 



On Andropogon sorghum Brot. occurring on the varieties broom corn, 

 amber cane, and sugar sorghum. 

 Queensland — (Bailey) . 



Victoria— Ardmona, 1895 (Robinson). Tatura, Feb., 1903 (Bald- 

 win). Tungamah, Feb., 1908 (Mallows) ; March, 1909. Lake 

 Rowan, March, 1909. Macorna, -Tune, 1909 (McDonald). 



The grain is converted into an enlarged projecting body consisting of 

 the firm fungus membrane on the outside and the slender columella is often 

 seen remaining in the centre after the bulk of the spores have been scattered. 



This smut has been placed under various genera, as seen from the 

 synonyms, but the mode of spore-formation shows that it belongs to Cin- 

 tractia. Ustilago cruenta Kuehn, is also found on Sorghum, but instead of 

 being confined to the flower it may occur on any part of the oanicle, and even 

 on the stem, while the spores are also larger on the average. 



Germination. — The spores germinate readily in water within 24 hours, 

 forming a 3-4 celled promycelium. Conidia are produced terminally or 

 laterally, but not usually in great abundance. Buckle or knee joints are 

 commoiily formed by the promycelium, and from these, as well as from the 

 end of the promycelium, slender threads are produced, supposed to be in- 

 fection-threads. In a nutritive solution, germination is more luxuriant, 

 more conidia are formed, and either when connected or detached, they give 

 rise to secondary conidia by sprouting in a yeast-like manner. Finally, 

 when the nutrition becomes exhausted, these conidia throw out slender germ- 

 tubes. 



(Plates XIV., XXXIX.) 



