THE FUNGI WHICH CAUSE PLANT DISEASE 169 



1-celled. The conidiophores, which serve better to characterize 

 the genus, are swollen at the end, and bear numerous sterigmata 

 (Fig. 120) on which the spores are borne basipetally in chains. 

 Sclerotia are sometimes formed. 

 The members of the genus are all saprophytes but some of them 



A 



Fig. 120. — Asper- 

 gillus, conidio- 

 phore. After 

 King. 



Fig. 121. — Penicillium, 

 showing a conidio- 

 phore; a, producing 

 chains of conidia, c; 

 «, three spores more 

 highly magnified. 

 After Longyear. 



cause injury to fruit in the tropics; for example, A. ficuum, Reich, 

 on figs; A. phoenicis Pat. & Del. on dates. 



Penicillium Link '* (p. 167) 



The ascocarp is much as in the last genus, with the asci 4 to 

 8-spored. It may develop directly from the mycelium or with the 

 intervention of a sclerotial stage. The characteristic conidiophore 

 serves to distinguish the genus by its mode of branching. Fig. 121. 

 Instead of being apically swollen as in the preceding genus it 

 branches repeatedly, the branches bearing terminal sterigmata 

 and giving the conidiophore the appearance of a brush; hence the 

 name. For species see page 573. 



