Lecture II — 21 — Occurrence of Mycorrhizae 



their being mycorrhizal or the reverse; and two species are thus re- 

 ported by him for the first and only time, namely, Cystopferis fragilis 

 (mycorrhizae occasional) and Onoclea sensihilis (ectotrophic) ; and 

 he records Adiantum pedatum and Pteridium aquilinum also mycor- 

 rhizal. DoAK (1927) finds the Adiantum species endotrophic while 

 Asm (1934) reports on A. flabeUuIatum. Pteridium is undoubtedly 

 mycorrhizal although the poll as it now stands is tied: Stahl (1900) 

 and Takamatsu (1930) insisting that P. aquilinum is not mycorrhizal 

 while LoHMAN (1927) and Rayner (1927) state that it is or appears 

 to be, and Rayner clinches the matter by presenting a photomicro- 

 graph of the apparent endophytic fungus within the root tissues. 



The large genus Aspidium is reported non-mycorrhizal by the 

 four who have reported upon it, — Frank, Stahl, Hoeveler, and 

 Lohman; yet surely these humus-dwellers deserve a reconsideration. 

 So, too, with Aspleniiim which Stahl and Janse reported as without 

 endophytes, and Polypodiinn which Stahl negated although Faber 

 (1925) seems to indicate mycorrhizae for P. Feei. Then Nephrolepis 

 and Blechnmn are recorded very casually only by Asai (1934) and 

 deserve more study. Last of all in this brief list of studied Poly- 

 podiaceae is Cliciropleuria, which is of special interest because occur- 

 rence of endophytic fungi in prothallia of C. hicuspis var. integri- 

 folia is added evidence in the author's opinion (Nakai, 1933) that the 

 genus should be removed from the Polypodiaceae and be placed in a 

 separate family, the Cheiropleuriaceae. This is the only case known 

 to the writer where mycorrhizae are made of service as a taxonomic 

 criterion. 



Symbiotic Fungi among Arthrophytes: — There is almost no 

 information extant regarding symbiotic fungi of the Equisetums. 

 Sadebeck in 1875 described browning of the prothallia of E. arvense 

 and E. palustre in culture, due tO' infection by a species of Pythium 

 which was named P. equiseti, but this was apparently a case of para- 

 sitic attack rather than of mycothallism. Janse said that forest dwell- 

 ing Eqiiisctae in Java appear never to have endophytic fungi in the 

 roots; Hoeveler (1892) found E. hie^nale and E. silvaticum not 

 mycorrhizal ; and Stahl found no trace of infection in Equisetum. 

 LoHMAN, in Iowa, lists E. arvense as containing an endophytic 

 Phycomycete while E. kansanum was lacking in mycorrhizae. Detailed 

 investigations of the Equisetums are yet to be made. 



Mycorrhizae and Mycothalll of Lycopsida: — Lycopodium has 

 received much attention. Following Treub's discovery of fungal in- 

 fection of a Javan lycopod, Bruchmann (1885) described similar 



