TREMELLA MYCETOPHILA 467 



vary in breadth from about 0-3 to 1 inch and upwards. Their 

 outer surface is covered with a hymen ium containing simple cyhn- 

 drical 4-spored basidia. 



In 1900 Atkinson,! accepting Peck's view of the nature of the 

 excrescences, described and illustrated them from specimens which 

 he found near Ithaca. " This plant," says he, " is interesting from 

 the fact that it is parasitic on a mushroom, Collyhia dryophila." 



In 1901 Burt ^ published a paper on the structure and nature 

 of Tremella mycetophila in which he pointed out that the excres- 

 cences could not be considered as belonging to a Tremella because : 

 (1) their substance is not truly gelatinous like that of the fruit-bodies 

 of the Tremellaceae but is fleshy (Fig. 194, D), as may well be seen 

 when the excrescences are allowed to dry ; and (2) their basidia 

 are not longitudinally and cruciately divided by walls, but are 

 simple and undivided like those of the Hymenomycetes in general 

 (Fig. 194, C). Burt therefore came to the conclusion that the fungus 

 " should not be included in the Tremellaceae but in the Thele- 

 phoraceae." He transferred the plant to the genus Exobasidium 

 and called it Exobasidium mycetophiluni (Peck) Burt. 



Burt ^ found that the excrescences produce not only basidia on 

 their exterior, but also conidia within their context (Fig. 194, D, 

 E, F). The dimensions of the basidiospores and of the conidia 

 he gives as 5-7 x 1-5-2 -5 fj, and 2 x 1-5 yu, respectively. The 

 conidia were present in the specimens which he collected during 

 eight seasons in two widely-separated localities, one in New York 

 State and the other in Vermont. 



In 1909, in the State of Minnesota, Miss Hone * found the sup- 

 posed Exobasidium, again on the cap and stipe of Collybia dryophila 

 (Fig. 193). Some of the gyrose excrescences were of extraordinary 

 size. She says " The fungus masses have very much the appearance 

 of a Tremella and were so large that they extended in folds over the 



! G. F. Atkinson, " Mushrooms, Edible and Poisonous, etc.," Ithaca, 1900, 

 pp. 204-205. 



- E. A. Burt, " Structure and Nature of Tremella mycetophila Peck," Bull, 

 Torrey Bot. Club, vol. xxviii, 1901, pp. 285-287. 



^ Ibid., p. 286. 



* D. S. Hone, " Two Basidiomycetes new to Minnesota : Exohasidinm myceto- 

 philum and Cantharellus retirugus,'" Minnesota Botanical Studies, 1909, pp. 61-63. 



