CHARACTERISTICS 07 THE TRUE FUNGI 



43 



gradations which preclude an absolute pronouncement as to whether 

 a plant is a saprophyte, or a parasite.^ Botanists generally concede 

 that the true fungi have been derived from filamentous algal ancestors 

 and the groups of algae from which the principal forms of fungi have 



Fig. 12. — Russula nigricans parasitized by Nyctalis aslerophora. {After Brefeld.) 



been derived are fairly well known. For example, it is believed that 

 such fungi as belong to the order OOMYCETALES have been derived 



1 Massee, George: On the Origin of Parasitism in Fungi. Annals of Botany, 

 xviii: 319. 



Ward, H. M.: Recent Researches on the Parasitism of Fungi. Annals of Bot- 

 any, xix: I. 



Bancroft, C. K.: Researches on the Life History of Parasitic Fungi. Annals 

 of Botany, xxiv: 359, 1910. 



