Medlar: Phialophora verrucosa 
201 
successive proliferation of the sporogenous cell below. After 
reaching maturity a septum is formed between the conidium and 
the parent cell and another conidium is produced. Although 
these spores are set free as soon as they are formed and are never 
produced in coherent chains, they are not at once scattered, but 
remain coherent owing to the presence of a gelatinous material 
which holds them together. A dozen or more may thus cohere 
Fig. I. Philophora verrucosa Medlar, a, stained specimen showing co- 
nidia formation and cellular detail ; b, c, after Thaxter, showing detail of 
sporogenous cell and conidia. 
to the cup-like extremity of the sporogenous cell forming a com- 
pact, globose mass. This “ cup and ball ” habit is very char- 
acteristic and the whole bears a close resemblance to a sporang- 
ium filled with endogenous spores. 
The individual conidium has a definite wall which is at first 
hyaline or faintly yellowish and becomes brownish with age, a 
