THE GENUS ENDOGONE 



GEO. F. ATKINSON 



Cornell University 



The genus Endogone was founded by Link in 1809, and for more 

 than a century its life history and taxonomic relationship have re- 

 mained very obscure. Notwithstanding this obscurity in relationship 

 and development, the structure of the mature plants is so simple and 

 characteristic, that comparatively few species have been accredited 

 to the genus which do not belong here. The fruit bodies are pulvinate, 

 rounded to reniform or irregular. In size they vary from 2-4 mm. 

 up to 2-3 cm. In life relation they are saprophytes. In habitat they 

 are hypogeous, epigeous or epixylous; and occur under or on the 

 ground, among or underneath fallen leaves, among the rhizoids of 

 mosses or roots of ferns, on dead wood, on sphagnum or other mosses. 

 In color they are whitish to yellow, brown or blackish. Approximately 

 seventeen species are known. The genus is cosmopolitan in distri- 

 bution. Species are known from Europe (including European Russia), 

 Ceylon, Tasmania, North America, Central America, South America 

 and the Fiji Islands*. 



General structure of the fruit body. — There is a peridium of slender, 

 interwoven hyphae formed by the terminal branchlets of the hyphae 

 which spring from the basal region, branch profusely and radiate to 

 the periphery. The interior constitutes the "gleba," the base or 

 central portion of the "gleba" is sometimes hollow or of less density 

 than the broad peripheral zone. The "gleba" is usually packed with 

 numerous, large thick walled "resting spores," oval, elliptical, or 

 spherical in form, and yellowish, grayish or dark brown in color 

 according to the species. These "resting spores" are 40-100 ^ in 

 diameter, are packed among the hyphae, and terminate certain 

 branches. They have been termed spores, sporangia, ampullae, or 

 asci, the latter term apparently having the preference, since it is 

 employed by a majority of writers. Several large elliptical spores in 

 an "ascus" have been described in one species {Endogone pisiformis), 

 a single large spore^ in an ascus in another species (£. reniformis), 

 and numerous minute spores in an ascus in several species. It is 



• ^ The spores in this species are probably the ordinary "resting spores," the 

 "asci" of authors, for Bresadola (1896, p. 297) says that neither the asci nor their 

 mode of dehiscence was seen. 



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