CHARACTERISTICS OF 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 Nyclalis aslerophora. (After Brefeld.) 



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



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

 any, xix: 1. 



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

 of Botany, xxiv: 359, 1910. 



