REVISION OF ENDOGONEAE. 315 



of the contents, and finally of the thick endospore, which, at maturity, 

 is invisible even with bright illumination, and is surrounded by a very 

 thin hyaline exospore. Though sometimes slightly irregular, or 

 slightly longer than broad, they are as a rule rather uniformly and 

 evenly spherical. In structure and development they correspond to 

 those of E. macrocarpa: but are even more closely comparable with 

 those of the species referred to below, which was found in the stomach 

 of a shrew. 



Endogone microcarpa Tul. 

 (Figs. 35-37.) 



Tulasne (1851), p. 182, Plate XX, fig. 2. Bucholtz (1912), p. 192, figs. 75-76. 

 nee Rabh. Fungi Europaei No. 2516. 



Glomus microcarpus Tulasne (1845), p. 63. 



This species has been recorded from America only on the authority 

 of Harkness (1899), who collected what he regarded as this form in the 

 forest at Mill Valley, California, No. 237. The description which he 

 gives does not make at all clear what he had before him; but the corre- 

 sponding number from the Harkness Collection, which has been kindly 

 sent me for examination by the Stanford University Herbarium, 

 proves to correspond to some of the forms of E. lactifiua, the spores 

 being clearly zygospores. 



A form, however, identical in all respects with the figures and de- 

 scription of Tulasne, has been kindly communicated to me by Dr. C. 

 W. Dodge; who collected it in June, at Aldercroft Creek, Los Gatos, 

 California. The spore-masses are well formed, though rather sriiall, 

 firm and similar to those of E. macrocarpa in form and color. The 

 spores are nearly spherical, 40^8 ju, and very thick-walled. 



Although there have been various records of this species in Europe, 

 it does not appear, from published accounts, that it has been recog- 

 nized with certainty since the original records of Tulasne, by whom it 

 was found in Italy and France; and it seems to have been confused 

 with smaller types of E. macrocarpa. Some of the latter from America 

 serve in a measure to bridge the gap between the two species, but E. 

 microcarpa, with a rather constant maximum spore diameter of 48 n, 

 seems clearly distinguished. Tlie accounts of Tulasne and of Buc- 

 holtz, who reexamined the original types, should be consulted for 

 further information in regard to this species. 



