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PLANT MORPHOLOGY 



of which are liberated into the air. Upon coming in contact with a suit- 

 able food supply, the conidia produce new mycelia. In Penicillium the 

 conidia arise from the ends of branched conidiophores (Fig. 98). In 

 Aspergillus the conidia are abstricted from the ends of short hyphae that 

 radiate from the enlarged tip of a conidiophore (Fig. 99). 



A B C 



Fig. 100. Development of the ascocarp of Aspergillus. A, sex organs; B, sterile hyphae 

 enclosing the sex organs; C and D, later stages, showing the development of asci. (From a 

 Turtox classroom chart.) 



Fig. 101. Section through a mature ascocarp of Aspergillus, showing the completely 

 enclosed asci, X 500. 



The sex organs are represented by two short, spirally twisted filaments, 

 the contents of which appear to fuse (Fig. 100). Then ascogenous hyphae, 

 bearing numerous small asci, arise from one of the filaments. These are 

 intermixed with and surrounded by sterile hyphae, those on the outside 

 forming a minute, globular, closed ascocarp. A fruiting body of this 

 type is known as a cleistothecium. There is no definite hymenium in the 



