CONJUGATING FUNGI— PHYCOMYCETES 



235 



110. — Hyphal bodies. 

 After Thaxter. 



guished by the production of numerous hyphae of large diameter 

 and fatty contents, which ultimately emerge from the host in 

 white masses of peculiar appearance, producing at their ex- 

 tremities large conidial spores, which are violently discharged 

 into the air and propagate the disease. 

 In addition to these conidia, the propa- 

 gation of the fungus, after long periods 

 of rest, may be provided for by the 

 formation of thick-walled resting spores, 

 adapted to withstand successfully the Fig. 

 most unfavourable conditions. These 

 resting spores, which may be either sexual (zygospores) or 

 asexual (azygospores), finally germinate and produce conidia 

 that are discharged in the usual fashion, and serve to infect 

 fresh hosts." 1 



Infection results from contact of one of the conidia which 

 adheres to the surface of the host, germinates there, and the 



germ-thread enters the body. After 

 entering, growth proceeds rapidly 

 and forms "hyphal bodies" (Fig. 

 110), which are short thick fragments 

 of variable size and shape, continually 

 reproduced by budding, until the 

 body of the host is more or less 

 completely filled with them. Having 

 absorbed the contents of the body, 

 these hyphal bodies germinate, each 

 one producing one or more threads, 

 which proceeds directly into the 

 outer air, and bears its conidia, or 

 it branches indefinitely, each branch- 

 let producing spores at the extremity 

 (Fig. 111). These are the conidia- 

 bearers, and their results the simple 

 asexual reproduction. Conidia are 

 formed by constriction or budding, 

 and when fully matured are forcibly ejected to a considerable 

 distance. The discharged conidium germinates at once, but, 

 1 Thaxter On the Entomvphthoreae of the United States, 4to, 1888. 



Pig. 111. — Conidiophores of 

 Entomophthora. S.P.C.K. 



