112 



MYCOLOGY 



when the reproductive organs are formed. Non-sexual spores, or 

 conidiospores, are borne on conidiophores which may remain within 

 the host (Albugo = Cystopus), or grow beyond the surface. They may 

 be either simple or branched. These conidiospores either germinate, 

 as in Phytophthora infestans and Peronospora nivea by means of zoo- 



FiG. 3S. — It Zoosporangium of Achlya racemosa; 2, escape of zoospores; 3, fiy- 

 covered by mycelium; 4, zoospores of fungus; 5, Achlya ferax with zoosporangia and 

 zoospores; 6, Achlya prolifera, 24 hours after germination of zoospores. 7, Achlya 

 monoica, with antheridia and oogonia; 8, Achlya conlorla. {After Henri Coupin, 

 Atlas des Champignons Parasites et Pathogenes de VHomme et des Animaux, pi. xviii, 

 1909.) 



spores which escape or by the protoplasm escaping (plasmatoparotis), as 

 in Peronospora densa, or by germ tubes, which in some species (Perono- 

 spora laclucm) appear at the end of the spore (acroblastic), or at the 

 side of the conidiospore (pleurohlastic), as in Peronospora radii. The 

 oogonia and antheridia, which are also present, are formed in the 



