REVISION OF ENDOGONEAE. 325 



marked difference observable even between ^^di^•iduals of the same 

 gathering. Thus of two individuals from the Torrend distribution, 

 one shows sporangia with an average diameter of 55-GO /x, while those 

 of the other average from 70-75 jx or slightly over, the latter dimen- 

 sions corresponding to the Californian and Naples gatherings. Al- 

 though Bucholtz reports a maximum diameter of 116 // for the latter, 

 I have not seen any above 100 // in the specimen examined. The New 

 Zealand form, on the other hand, is distinctly larger, the maximum 

 diameter being 120 /x, diameters of 100 ju being common and the 

 average being 80-85 n. 



The form of the sporangia is normally subspherical, but may be 

 irregular, longer than broad, or even broader than long, or subangular 

 from mutual pressure. The wall usually appears thin, and tends to 

 follow the contour of the contained spores; but, especially when 

 treated with potash, may form a clear gelatinous envelope around the 

 spores, 4-5 jj. thick. The spores are somewhat variable in size, sub- 

 angular from pressure, but often become spherical when free, and 

 possess a distinct thin wall. None have been seen, even in the Tor- 

 rend material, which closely approach the measurements given by 

 Bresadola, 15-28 X 15-17 ju. Measured in the sporangium they 

 rarely seem to exceed 14-15 ix, and usually average from 8-12 fi: 

 although when set free and treated with potash they may reach 20 n 

 occasionally. They form a rather viscous^ mass, and when the 

 sporangium is violently broken, are apt to escape in more or less 

 coherent groups. The filaments, on which the sporangia are borne 

 terminally, are branched and usually rather copiously septate, even 

 submoniliform; the contents above the upper septum, which is often 

 a short distance below the sporangium, being often divided into 

 several superposed spores. 



From its general characters this form could probably be cultivated 

 with ease by anyone who was fortunate enough to find it in a fresh 

 condition, and a thorough examination of its development in pure 

 cultures is very much to be desired. 



Doubtful or Excluded Species of Endogone. 



Reference has been made above to the occurrence of spores of En- 

 dogone in the digestive tract of animals, and in this connection it may 

 be mentioned that in one of these instances spores and mycelium were 

 found in the stomach of a shrew, sent me by Mr. Judd from the 

 vicinity of Washington, D.C. In this material, scanty but typical 

 Endogone filaments bear a few very large spores, some of them 240 /x 



