Ur OCX Wis. 199 



On Sii'pa luehmanni Reader. 



Victoria— Mallee, Oct., 1898 (C. French, jun.). 



Tills species is distinct from U. occulta, as the spore-l)all.s are considerably 

 larger iu size, and the individual spores are smaller. 



The grass is provisionally named, as Reader states that there is a certain 

 amount of hybridism taking place among the species of Stipa, and doubtless 

 new forms will be the result, so that it is just possible that this species — 

 S. luehmanni — may be reduced to a variety. 



(Plate LI.) 



Triticum. 

 67. Urocystis tritici Koeru. 



Koernicke, Hedw. XVI., p. 33 (1877). 



Urocystis occulta (Wallr.) Rab, in Sacc. Syll.f?VII., p. 515 (1888). 



Sori in leaves, leaf-sheaths, stems, and occasionally on glumes, forming 



elongated streaks running parallel to one another, at first covered 



by the raised leaden-coloured epidermis, which gradually decays in 



patches, allowing the escape of the black powdery spores. 



.Spore-balls globose, ellipsoid, or oblong, bright golden-brown, 

 variable in size and shape, l()-40 /( diam., or 24-40 x 24-32 ^(> 

 average 32 x 24 /(. 



Spores spherical or oval, 1-4 in ball, occasionally 5, 2-3 common, 

 9-12 ^t diam., or 12-lG /< long ; sterile peripheral cells generally 

 completely investing spores, or may be only partial, very pale-yellow, 

 ellipsoid to globose, and bulging, 9-12 /ii long. 



On Wheat. 



Victoria — Ballarat, Dookie, Longerenong, Netherby, Rochester, 



Ruthergien, Tungamah, Yarrawonga, &c. 

 New South Wales — Common. 

 Queensland — Hodgson District, 190G (Tryon). 

 South Australia — Common. 

 This species is mainly separated from Urocystis occulta on account of the 

 spores from the one not infecting the other. The spores are commonly two 

 in a ball, although three and four are also met with, and the investing layer 

 of sterile cells is generally complete. The spore is delicately punctulate on 

 the surface, but this is more marked in Ur. occulta. 



Koernicke- had determined the smut on wheat sent from South Australia 

 by Dr. R. Schomburgk iii 1877 as a new species, Urocystis tritici, and according 

 to him Ur. occulta is distinguished from Ur. tritici by the more distinctly 

 punctulate spores, which are not generally completely invested by the sterile 

 cells, and the sterile cells being more compressed and flattened. 



Germination. — The spore germinates in water, sometimes in 24 hours, and 

 sometimes taking a fortnight, according to the age of the spore and the season 

 of the year. It produces a promycelium which may either be unicellular 

 or 2-3 celled. At the apex the conidia are formed, varying from 2-0. but 

 generally 3-4. They are at first upright and crowded together, but gradually 

 diverge so that they stand out as finger-like })rocesses. They are normally 

 cylindrical, rounded at the free end, and unicellular, but may develop one 

 or two septa. They vary in size, but are generally 12-15 m long, and 3 /( broad. 



