Lecture III —39-- Fungal Endophytes 



Phycomycete Mycorrhizal Fungi : — The records for these fungi 

 before 1920 are somewhat uncertain because it was not until recent 

 years that phycomycetous mycorrhizae were regarded as constant 

 features of nature. It is true that Treub, Bruchmann, and Goebel 

 had independently found Pythium in prothallia of lycopods; while 

 Jeffrey had assigned the endophyte of Botrichium to the same 

 genus. Dangeard had found a chytridiaceous fungus on Tmesipteris 

 which he regarded as mycorrhizal ; and there are a few other records 

 of the same sort. 



It was Peyronel who brought the "Phycomycete mycorrhiza" 

 to our attention, commencing in 1922 with a study of cereal grains 

 that were brought to his station for a study of diseased condition. 

 Peyronel found that these cereals, instead of being autotrophic, 

 possessed mycorrhizal infection, — the infection being considered 

 mycorrhizal because the hosts were "perfectly normal". From this 

 study Peyronel continued : He saw quickly that endotrophic fungi 

 are of two major sorts, — the first possessing arbucles and vesicles 

 and the second only mycelial pelotons (found chiefly in orchids ex- 

 cept that Mollberg found vesicles in certain orchids). Later (1924) 

 Peyronel described three species of Endogyne involved in forma- 

 tion of endotrophic mycorrhizae on herbaceous phanerogams, the 

 first characteristic of peaty, swampy soils, the second exclusively 

 hydrophilous, and the third found on Euphorbia dulcis. Other species 

 of Endogyne were reported in 1937 from the Val Valdesi, producing 

 endotrophic mycorrhizae on Viola and other herbs. In the same 

 year, he published on endotrophic mycorrhizae of the Alps at Kleinen 

 St. Bernhard, and noted that conditions in a cultivated garden were 

 markedly less favourable for growth of the mycorrhizal fungi than 

 in the natural habitat. 



Interest in the phycomycetous mycorrhizae had been stimulated 

 by Jones (1924) in a publication in which he recorded the discovery 

 "that the roots of nearly all our common leguminous crops, wherever 

 grown, are extensively invaded by a characteristic fungus which has 

 previously been known as a mycorrhizal fungus. So abundant is this 

 fungus that it appears unlikely that many plants of alfalfa, clover, 

 peas, and other legumes ever reach maturity without having their 

 roots more or less invaded. . . The taxonomic position of the fungus 

 has not been determined but it appears to belong among the Phy- 

 comycetes." Jones gave a list of other plants besides legumes in 

 which this same sort of mycorrhizal invasion had been found. 



This paper of Jones' inspired Samuel (1926) to work in South 

 Australia, and he reported the same sort of infection in 27 legumes, 

 30 Gramineae, and in herbs of the families Liliaceae, Ranunculaceae, 



