148 Ustilago. 



Spores globose or subgiobose to elliijsoid, olive-brown to blackisli- 

 brown, often with a clear strip on one side indicating a thimier 

 portion of the wall, perfectly smootli, 6-9 /i( diam. or 8-11 x 5-8 /(. 

 On Hordeuni vulgare L. — Barley. 



No doubt it occurs in all the States, although it has only been specially 

 noticed as under : — 



Victoria— Port Fairy, Dec, 1903, and Jan., 1905. Mordialloc, Sep., 

 1904. Camberwell, Nov., 1906. Toorak, Oct., 1907. Dookie. 

 Dec, 1907. Goulburn Weir, Feb., 1909 (Parris). Bacchus 

 Marsh, March, 1909. 

 Tasmania — Hobart, Dec, 1906 (Rodway). 



South Australia — 1907. Found in shipments of barley to Victoria. 

 In a shipment of wheat from San Francisco, arriving here in March, 

 1903, there were heads of barley and detached portions mixed up with it 

 badly affected with this smut. Among the species of Ustilago on wheat, 

 oats, and barley, there is not sufficient distinction in the size of the spores to 

 discriminate between them, although the largest are found in U. hordei. It 

 has also to be noted that it is the only one with a smooth epispore. The two 

 species of smut found on cultivated barley — naked and covered smut — 

 have only recently been separated, and the}?^ were formerly included under 

 U. segetum. The hard and persistent mass of spores in the one case, however, 

 and the powdery mass dispersed when mature in the other, enable them to 

 be readily distinguished. 



Spore formation. — A transverse section of the ovary shows the epidermis 

 still surrounding it, and the spores are in patches scattered throughout the 

 internal tissue. In each individual patch surrounded by plant tissue, when 

 the spores are not all fully mature, they are seen to be formed in the sporo- 

 genous hyphae in regular gradation from the minute colourless to the mature 

 coloured spore. 



Germination. — Spores were germinated both in water and in hay infusion, 

 and they put forth a germinal tube which divided by transverse septa into 

 four cells, and canidii were produced laterally as well as at the apex. The 

 conidia multiplv in a yeast-like manner, and form sprouting conidia. 



(Plates XL, XXVI., XXVII.) 



Hordewn. 

 3. Ustilago nuda (Jens.) Kell. & Sw. 



Kellerman & Swingle, Ann. Rep. Ivans. Agr. Exp. Sta., p. 277 



(1890). 

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



Ustilago segetum (Bull.) Dittm. * 



Sori in spikelets, forming dense brownish-black masses, Avith a bronze- 

 green tinge, at first covered by the flowering glume, which is 

 converted entirely into a thin leaden-coloured membrane, or the 

 awn may remain green, then when free from the leaf -sheath becoming 

 naked, and the loosely adherent spores are scattered, leaving the 

 axis of inflorescence exposed. 



Spores globose to subgiobose or ellipsoid, olive-brown, often with 

 clear strip on one side, distinctly but finely echinulate, 5-7 /< diam., 

 or 6-7 X 4-5 /'. 



