214 



MORPHOLOGY. 



these views, might be presented here to show the general relationships of 

 the fungi studied, with the addition of a few more in orders not represented 

 above. It should be borne in mind that the author in presenting this view 

 of classification does not necessarily commit himself to it. It is based 

 on that presented in Engler & Prantl's Ptlanzenfamilien. There are three 

 classes. 



I. Class Phycomycetes (Alga-like Fungi). 



1. SUBCLASS OOMYCETES. 

 432. These arc the egg-spore fungi. They include the water mold 

 (Saprolegnia), the downv mildew of the grape (Plasmopara), the potato 



Chytrids. A, Harpoch^'trium hcdenii, parasitic on spirofivra threads; a, sickle- 

 form plant; 6, the sporangium part with escaping zoospores; c, old plant pro- 

 liferating by forming new sporangium in the (.tld empty one; ti, zoospore; e, two 

 young plants just beginning to gro^v. 5, Rhizophidium globosum parasitic on 

 spirogyra. Globose sporangium with delieate threads inside of the host, zoospores 

 escaping from one. C, Olpidium pendulum, parasitic in spirogyra cell. Ellip- 

 tical sporangium with slender exit tube through which zoospores are escaping. 

 D, Lagenidium rabenhorstii parasitic in spirogyra cell. Two slender sporangia 

 with exit tubes through which protoplasm escapes forming a rounded mass at the 

 end of tube, this protoplasm forming biciliate zoospores. 



forming swarm s])orcs "which unite ti) furm a small ])lasmodium, which in 

 turn grows to hirm a large plasmodium or protoplasmic mass. It is doubt- 

 ful if thc\' are an\' luoru phuU than animal organisms. l'',xamples: Trichia, 

 Arcyria, Stemonitis, I'hvsarum, Ceralionivxa, cli .. on rotten wood; Plas- 

 modiophora brassicie is a parasite causing (hil> foot of cabbage, radishes, 

 etc. It lives within the roots, causing large knots and swellings on the S^inte. 



