THALLOPHYTA: FUNGI 



125 



produces a substance, called penicillin, that has remarkable germicidal 

 properties. It has recently come into prominence as a valuable agent 

 in the treatment of many infections and diseases caused by certain bac- 

 teria, particularly cocci. Its great advantage over many other drugs lies 



Fig. 98. Branching conidiophores of PeniciUium producing chains of conidia, X800. 



B E 



Fig. 99. Aspergillus niger. A to E, successive stages in the development of a conidiophore 

 and its conidia, as seen in optical section, X400. 



in its almost complete nontoxicity to the human body. Substances like 

 penicillin are called antibiotics.^ 



The mycelium of the Plectascales produces special branches, called 

 conidiophores, that cut off chains of spores, or conidia, enormous numbers 



1 Most antibiotics, including streptomycin, aureomycin, and Chloromycetin, are 

 derived from actinomycetes, a group of organisms of which some are mold-like and 

 others bacteria-like. They are variously classified with the Fungi Imperfecti, the 

 bacteria, or as a distinct group of fungi. Some are parasites but most are saprophytes 

 prevalent in the soil. 



