CYSTOPUS. 



123 



Cystopus (Albugo). 



The mycelium is branched and grows between the cells of 

 living plants, obtaining its nourishment by means of haustoria. 

 The conidial cushions rupture the epidermis of the host. The 

 conidia or sporangia are smooth-coated, and are produced 

 acropetally in chains on short stalks from which they fall off 

 separately when ripe. The sporangia germinate and discharge 



Fig. 33. — CyUopaa 



lilaiits uf Cu,>stlla lw.,m paslorin. The fuiigUK 



has caused distortion and thickening ; the white porcellanous conidial cushions 

 shew up distinctly on the dark background, (v. Tubcuf phot.) 



swarming spores with two unequal lateral cilia. The egg-cells, 

 produced singly in each oogonium, are fertilized by an autheridiuni. 

 The thick-walled oospores remain enclosed in the intercellular 

 spaces of the host-tissue, and on germinating in spring discharge 

 swarming spores. 



Cystopus candidus (Pers.) Lev. White liust. This fungus 



