404 Transactions. 
1. UsriLAGO (Persoon) Roussel. 
Roussl., Flora Calvados, ed. 2, p. 47, 1806. 
Uredo § Ustilago Pers., Syn. Fung., р. 224, 1801. Ustilagidium Herzb., in Zopf, 
Beitr. Phys. Morph. Org., vol. 5, p. 7, 1895. 
Sori forming dark-coloured pulverulent Spore-masses in various parts 
of the host, usually in the inflorescences. 
Spores single, globose’ or angular ; epispore coloured, smooth or variously 
sculptured ; germinating by a short septate probasidium, which either 
produces conidia laterally and terminally, or develops directly into ап 
infection hypha. 
Distribution : World-wid 
The pulverulent naked sori and single spores serve to separate this 
from any other genus, with the exception of Tilletia. The production of 
probasidia bearing lateral conidia serves to se parate those species of Ustilago 
possessing this character from those of Tilletia, which produce probasidia 
ut i j les 1 
are produced acrogenously being placed in Tilletia; if intercalary, in 
Ustilago. The matter would be simplified if the genus Ustilagidium were 
erected to contain those forms in which no conidia are present; but this 
would necessitate, in order to maintain consistency, the erection of another 
genus to contain such species as Г, stilago bromivora, where the method of 
germination departs considerably from the normal. 
In New Zealand, members of this genus have been found only on 
the Gramineae, but elsewhere the have been recorded on the following 
additional families : Cyperaceae, Liliaceae, Polygonaceae, Portulaceae, 
Caryophyllaceae, Oxalidaceae, and Onagraceae. 
pore-formation.—This was first worked out by Fischer von Waldheim 
(1869). Following their differentiation, gelatinization of the sporiferous 
spore during its development, but gradually becomes less conspicuous until 
at maturity it has entirely disappeared. : 
Germination.—In the genus three methods may be observed: in Usti- 
lago Avenae the probasidium becomes transversely septate, and from it 
arse numerous lateral and ‘one terminal conidia; іп 17, bromivora the 
