46 A NEW SMUT IN A NEW GENUS OF GRASS. 



into spores at intervals or close together. The spores are at first 

 small, ellipsoid becoming round, colourless, smooth and thick- 

 walled Then of an olivaceous tint, passing into a golden-hrown, 

 with ecliinulate wall, and finally of a deep rich brown, with wall 

 densely spiked. 



Germination. This took place in a hanging drop of tap-water, 

 where a large proportion of the spores germinated, and the 

 photographs were taken after five days. The germinal tube or 

 proniycelium varies considerably in length, and is divided into 

 numerous segments, which are sometimes constricted at the septa, 

 and at first densely vacuolated. 



Numerous fusiform, colourless conidia are given off laterally 

 and terminally, in chains of three or more, and each conidium is 

 3-6 /x long. 



The new genus of grass belongs to the group Ayrohtv/ece, and 

 there is a smut on Amphipoynn, from South Australia, named U. 

 tepperi Ludw., which somewhat approaches this one, but the 

 aculeate spores are larger, and the sori are in the stems, as well 

 as in the flowers Altogether it is a distinct species, from the 

 mode of germination, the relative size of the spore, and its dense 

 echinulation. 



It is named in honour of the Professor of Botany, at Melbourne 

 University, and Government Botanist for Victoria; and this is 

 peculiarly appropriate, since it is the fir.st smut recorded on a 

 native grass belonging to NVest Australia, and which has been 

 determined by Professor Ewart as a new genus. 



EXPLANATION OF PLATE. 



Plate i. 



Ustilago ewarti McAlp. 



Fig. L —Smutted panicles of Sarga fitipoidea Ewart ami Wliite, with 



liealthy ^raiii at side; (nat. .size). 



Fig. 2. — Spores densely covered with spikes; ( x 500). 



Figs. 3-4. —'^poi'es germinating, and producing more or less slender septate 

 prom^'celia, with lateral and terminal conidia in chains; { x 500). 



