250 



A TEXTBOOK OF THEORETICAL BOTANY 



Aspergillus (Eurotium) herbariorum 



This Fungus is a saprophyte on fatty substances and forms one of the 

 most frequent contaminants of food. Some species are parasitic on man 

 and animals, but the majority Hve as saprophytes. The mycehum consists of 

 filaments of multinucleate cells, and ramifies over the surface of the sub- 

 stratum on which it lives, sending up vertical hyphae which bear the asexual 

 reproductive organs. The name Eurotium was originally applied to the 

 sexual stage, while the name Aspergillus was used for the asexual. This was 

 due to the fact that until comparatively recently the two stages were regarded 

 as those of distinct Fungi, owing to the fact that either stage could apparently 

 continue indefinitely without the appearance of the alternative stage. This 

 tendency among Fungi for the asexual stage to continue generation after 

 generation without the intervention of a sexual stage we have already met 

 with in Mucor. It is equally true of many of the Ascomycetes, in fact there 

 exists a large group of Fungi, termed the Fungi Imperfecti, which includes 

 many important plant pathogens, and comprises Fungi in which only the 

 asexual stage is known (see Volume IV). 



Asexual Reproduction 



The asexual reproductive bodies are borne on conidiophores (Fig. 241) 

 These arise as vertical hyphae which grow out from the mycelium. They 

 are thick and are not divided by septa. The tips of these conidiophores 



A B 



Fig. 241. — Comparison of conidiophores. A, Aspergillus tiiger. 

 B, Penicilliutn catnembertii. 



