PERONOSPORE.*: 



639 



the ob'gone, and discharges into the latter the contents of the 

 antherid, thus causing its protoplasmic contents or * ob'sphere ' to 

 develop into the impregnated ' oospore.' The further history of the 

 oospore is singularly different, even in different species of the same 

 genus. In some it germinates directly into a new mycele ; in others 

 it breaks up into a number of swarm-spores or zoospores ; each of these 

 comes to rest, and after a time germinates into a new mycele. In 



K 



FIG. 477. A-G, Cystopus candidus : H, Phytophthora infestans. A, branch of 

 mycele growing at the apex, t, with haustoria, h, between the cells of the pith of 

 Lepidium sativum', B, branch of mycele bearing gonids ; C, D, E, formation of 

 swarm-spores from gonids; F, swarm-spores germinating; G, swarm-spores 

 germinating on a stomate and piercing the epiderm of the stem of a potato at H. 

 After De Bary ; magnified about 400 times. From ' Outlines of Classification and 

 Special Morphology of Plants,' by Dr. K. Goebel. 



addition to the sexual organs of reproduction, many species of Perono- 

 sporese also produce non-sexual S2>ores or gonids, which are borne on 

 special branches springing erect from the mycele, the sporophdres or 

 yonidiophores. A similar difference is exhibited in the further 

 development of these spores. Either they germinate directly in water 

 into a new mycele, or the protoplasmic contents break up into a 

 number of zoospores which germinate in the stime way. In those 



