70 Transactions British Mycological Soctety. 
sections. The sections are then stained in lacto-phenol-anilin 
blue and washed out with absolute alcohol until only the hyphae 
and young spores remain deeply stained. 
The first recognisable stage is the formation of a knot of 
hyphae by the interweaving of short branches from one, or 
more usually, several neighbouring hyphae. The central hypha 
swells up at the tip to form the central fertile spore, which at 
this stage is thin walled and contains a single large nucleus 
embedded in the dense granular cytoplasm. Gradually the 
spore wall is thickened and modified into some form of ligno- 
cellulose. During the process the surrounding hyphae become 
adpressed to the spore wall, develop septa at short intervals 
and round themselves off to form the investing sterile cells. 
These sterile cells thicken their walls slightly and ultimately 
lose their protoplasmic contents. The chlamydospores are not 
formed in any definite order since contiguous spores are often 
at very different stages of development. The increasing pressure 
due to this constant production of spores gradually forces the 
mesophyll cells widely apart and ultimately ruptures the 
epidermis. The spores fall to the ground and after passing 
through the necessary resting period germinate and begin the 
life cycle again. 
The writer desires to express his thanks to Prof. Thaxter 
and to the Connecticut State experimental station for kindly 
furnishing him with a copy of Prof. Thaxter’s paper on U7vo- 
cystis Cepulae. 
SUMMARY. 
The life history of Uvocystis Cepulae is relatively simple, 
chlamydospores giving rise to promycelia which develop sporidia 
laterally. This observation, originally made by Thaxter, and 
confirmed by the writer disposes of the view now held that the 
terminal production of sporidia is a generic character of Uro- 
cystis. There is no conjugation of sporidia. Under suitable 
conditions the sporidia may bud repeatedly though this probably 
does not take place normally. Infection is in all probability 
via the root hairs in the collar region. There is no interpolation 
of gonidia in the life cycle as in some genera such as Tuburcinia. 
The cytology of the fungus has not been studied in the present 
investigation. 
BIBLIOGRAPHY. 
(1) Corton, A. D.—Onion Smut—A disease new to Britain. Journal of the 
Board of Agriculture, vol. xxv1, No. 2, 19109. 
) THaxtER.—The “Smut” of onions. Annual Report, Connecticut Agri- 
cultural Experiment Station, 1889. 
) PamMEL and Kinc.—Iowa State Bul. No. 131. 
) Harr and Stevens.—Fungoid diseases of Economic plants, 1913. 
) Reppicx, D.—West N.Y. Hort. Soc. Proceedings, No. 58, 1912. 
) PLowricHtT.—British Uredineae and Ustilagineae, 18809. 
