Impression cultures of leaves upon nutrient gelatine, incubated for three days 



(Sept. 4-7), showing the colonies developed. 



A, upper surface of the leaf of an artichoke {Helianthus tuberosus) ; B, under surface of the 



leaflet of a potato (So/aiiii»i tid>efOS7ui/). 



(Reproduced by kind permission of the British Mycological Society.) 



p. 204] 



