r St i I ago. 155 



" I 1 Cynodon. 



10. Ustilago cynodontis V. Hciin. 



P. H.Miiiiims, Eiml. i^ot. -laliili. XI\'.. ]). :)«i9 (1S91). 

 Sacf. Syll. XIV., p. 41ii (1899). 

 Sori involviii»i' the young inflorescence and entirely destroyin<i- it while 

 still enclosed in its enveloping leaves, black in the mass and pow- 

 dery ; in some cases the digitate spikes have expanded before the 

 florets are destroyed : also in the axis of the inflorescence and 

 encircling it. 

 Spores olivaceous, subglobose. occasionally ellipsoifl. jilino-t smooth, 

 7-8 /( diam. or 9-10 x 5-7 //. 

 On Cynodon dactylon Pers. — Couch grass. 



New South Wales — Svdnev Botanic Gardens, Jan. and Oct.. 19<)7 



(Ch-el). Sydney," Feb.^, 1909 (Baker). 



This species was first obtained from Abyssinia, then it was sent from 



Simla in 1891 to Brefeld, who succeeded in germinating the spores. Magnus* 



notes its distribution in Europe, Northern Africa, and India, and concludes 



that the Ustilago on the same host-plant in America is quite distinct. 



In Australia it has only hitherto been found in the Sydney Botanic Gardens 

 and on a lawn near Sydney. Although the host-plant is plentiful in Victoria, 

 no signs of smut have appeared on it. 



Spore- formation. — Cross-sections of the stem and of the axis of the affected 

 inflorescence show the plant tissues in the centre surrounded by the vascular 

 bundles, and the hyphae are seen ramifying in the cells outside these bundles. 

 The mycelium bursts through the epidermis and forms a compact mass of 

 filaments from wdiich the spore-bearing hyphae are produced. The very 

 minute colourless spores are at the base, and they gradually increase in size 

 and assume a dark olivaceous tint towards the outside. Here and there are 

 slender strands of hyphae radiating towards the circumference and if the 

 spores were more firmly agglutinated together, the characters would be those 

 of a Cintractia. 



Germination. — This occurred in water, and in a nutrient solution every 

 spore germinated. Spores were taken from a specimen collected in October, 

 1907, and in December, 1908, they germinated freely, thus showing that they 

 retain their germinating power for more than a year. The spore puts forth 

 a three-celled promycelium which produces elongated conidia laterally and 

 at the apex. In some cases tw^o promycelia are produced from one spore, 

 the spore itself being divided into two by a septum and each division giving 

 rise to a promycelium. The conidia multiply copiously by sprouting, and 

 these sprouting conidia, where they reach the surface of the fluid, become 

 aerial conidia. 



(Plates XXII., XXXIV.. Llll.) 



Triodia. 



11. Ustilago hieronymi Scluoet. 



Schroeter, Hedw. XXXV.. p. lM.3 (189(i). 

 Clinton. North Am. Ust., p. 3.'>8 (1904). 

 Sacc. Syll, XIV., p. 417 (1899). 

 Sori in the leaves and leaf-sheaths, usually forming elongated ])ustules 

 covered by the leaden-coloured cuticle which usually rujitures, 

 exposing the mass of powdery black spores. 



Spores dark-brown, globose to ellipsoid, distinctly warted, 10-] 2 // 

 diam. or 10-13 x 7-10 /', occasionally reaching a length of l~) r- 



