Ciutractia. 17 1 



Dichehchne, Slifa. 

 27. Cintractia hypodytes (Schl.) Dietel. 



Diotel, llemibasidii in Eno'I. and Prant. Naturl. Pflanzenf., 



p. 8 (1900). 



Sori linear, at first covered by sheath, extending the entire length of the 



upper intcrnodes and completely surrounding them with a firm 



blackish coat of agglutinated spores, which ultimately become 



powdery. 



Spores in a dense layer, minute, dark olivaceous, globose or shortly 

 ellipsoid, with granular contents, smooth, held together by a gela- 

 tinous material, 4-5 /« diam. or 4-6 x .3-4 /<. 

 On Dichehchne crinita Hook f. 



Victoria — Ardmona, 1895 (Robinson). Emerald, March, 1907 

 (McLennan). Dookie, Dec, 1907. Dookie, Nov., 1908 (Brit- 

 tlebank). Myrniong, Jan., 1910 (Brittlebank). 

 South Australia — Banks of Torrens River, Adelaide, Oct. (Tepper). 

 On Stifa flavescens Labill. 



Victoria — Myrniong, Nov., 1904. 

 On Stipa setacea R. Br. 



Victoria — Ardmona, Nov., 1898 and 1899 (Robinson) ; Mvrniong, 

 Dec, 1897 and 1902 (Brittlebank). 



The upper internodes particularly are more or less completely surrounded 

 throughout their entire length and the pedicels of the spikelets are often 

 affected. 



Generally the sheath encloses the diseased portion and there is little or 

 nothing to indicate a smut beyond the absence of an inflorescence. 



Spore formation.— A cross-section of the stem shows the tissues of the 

 plant to be apparently unaltered, only the surface composed of the epidermis 

 is rather irregular in its outline. The mycelial hyphae ramify in the paren- 

 chymatous cells and reaching the surface form a compact gelatinous mass 

 of filaments. The outwardly directed spore-forming hyphae show the spores 

 in various stages of development, at first minute and colourless and radiating 

 in lines until they become fully mature and coloured. They form a continuous 

 dense layer on the outside, where they are held together by a gelatinous 

 material, but Avhen thoroughly mature they fall away readily from the dry 

 stems. 



A specimen of Ustilago hypochjtes (Schl.) Fr. on Stipa spartea Trin., in 

 Clinton's Exsicc. Ustilag. C. 71, showed the same structure and in sections 

 where spore-formation was not too far advanced the spores were seen to be 

 formed from the inside outwards. 



Germination. — A brief description has been given by Brefeld^ and an 

 illustration by Winter^. Brefeld says that the spores germinate readily in 

 water and in nutritive solutions they form mycelial hyphae, but in numerous 

 cultures long-continued he did not succeed in obtaining conidia. "Winter, 

 however, figures a spore germinating with one conidium. Plowright^ says — 

 " Although I have tried many times, I have never succeeded in getting the 

 spores of this species to germinate," and yet according to Berkeley-, the 

 smut may be prest^rved in a garden for years by simply introducing infested 

 plants. 



(Plate XXXIV.) 



