REVISION OF ENDOGONEAE. 305 



a compact continuous spore-mass, without incorporated foreign 

 material, and in which the origin of the spores and spore-groups is 

 quite different and apparently non-sexual. 



Endogone incrassata nov. sp. 

 (Figs. 17-19.) 



Fruiting body even or somewhat lobed, yellowish, with a whitish 

 scaly or reticulate crust variably developed, about 2-5 mm. in diame- 

 ter when dry. Gleba firm and compact, yellowish; the hyphae thin- 

 walled and vesicular, or running in strands or bundles between the 

 spores; the thin peridial region of more slender thick-walled filaments. 

 Spores scattered thickly, without definite arrangement, throughout 

 the mass of the gleba, which contains no foreign matter; more nearly 

 isodiametric, somewhat irregular in outline, subspherical to broadly 

 oblong, at first filled with rather uniform yellow subspherical fatty 

 granules, about 3-5 /j., the continuous endospore clearly defined, 

 thinner than the exospore; the two about 8 /x thick; the exospore 

 becoming much thickened, 16-20 /jl, intruded toward the center and 

 pushing the endospore into folds, the contents losing its color and 

 granular character. The spores 66 X 64-75 X 85 /x. 



Under spruce, about two inches below the surface of the cover; 

 with a distinct aUiaceous odor. Gerrish Island, Kittery Point, Maine; 

 August, 1896. 



Three specimens of this species were found associated, and close by a 

 single individual of E. radiata, of which it may possibly prove the 

 sexual form. The gleba is so dense, and its elements surrounding the 

 spores so vesicular, that it has been impossible to make out with cer- 

 tainty the character of the gametes which are evidently small, not 

 clearly distinguished and almost obliterated by the enlargement of the 

 spores and the consequent pressure. In a few instances, appearances 

 have been seen such as are represented in Figures 18-19; but, in the 

 dense pseudotissue about the spore, it is quite possible that the appar- 

 ent conjugating spore-origin may be in reality due to an accidental 

 juxtaposition of gleba elements, bearing a superficial resemblance to 

 conjugating structures. 



The spores when fully matured. Figure 19, resemble those of E. 

 tuberculosa, Figure 14, although the wall of the exospore becomes rela- 

 tively thicker and the endospore is thrown into deeper and more 

 complicated folds by its intrusion. In this condition it is quite hya- 



