ATKINSON: THE GENUS ENDOGONE 9 



but I am strongly inclined to believe that they are spores of some 

 parasite. 



Relationships of Endogone 



The coenocytic mycelium with no true cross walls, except those 

 which separate reproductive organs from the mycelium, with the 

 formation of resting zygotes soon after the conjugation of gametangia, 

 are phycomycete characters. The method of conjugation of equal or 

 slightly unequal gametangia indicates a closer relationship with the 

 Zygomycetes than with the Oomycetes, although in Endogone lactiflua 

 the content of the small gametange, or antherid, flows into the larger 

 one which is comparable to the oogone. In Zygorhyncus the two 

 gametangia are very unequal in size, but the zygote is formed within 

 and includes all of both gametangia, a strictly zygomycete feature. 

 In Conidioholus the gametangia are of very unequal size, and are 

 worthy of being distinguished as antherid and oogone. The content 

 of the antherid passes into the oogone within which the zygote is 

 formed. In Basidiobolus" also there is a supplying gametange and a 

 receiving one, but other features of these genera, especially conidial 

 formation, show such a close relation to Empiisa that they are generally 

 regarded as members of the zj^gomycetes with a leaning toward the 

 oomycetous type of fructification, but not having reached the char- 

 acteristic feature of egg differentiation in the oogone. Endogone 

 departs from the usual type of zygote formation present in the zygo- 

 mycetes. The zygote is an outgrowth from the conjugation point of 

 the gametangia (£. sphagnophila), or from the larger gametange 

 (£. lactiflua, rarely in E. sphagnophila) . A similar situation, however, 

 is present in Piptocephalis freseniana and in Enipusa {Entomophthora) 

 fresenii, where the zygote is an outgrowth of the point of conjugation 

 much as in Endogone sphagnophila. In Empusa occidentalis, echino- 

 spora, sepulchralis, etc., the zygote is an outgrowth of one of the 

 gametangia, a situation similar to that in Endogone lactiflua, or some- 

 times it arises from the point of conjugation in these species oi Empusa. 



In the selection of a single sex nucleus in each gametange, E. 

 lactiflua presents a situation similar to that in the Peronosporales, 

 though there is no differentiation of ooplasm and periplasm in the 

 oogone of Endogone lactiflua, as there is in the Peronosporales. In E. 

 sphagnophila there is no sex selection of nuclei in the gametangia so 

 far as we can determine, for all of the nuclei without manifesting any 

 differentiation pass with the cytoplasm into the new outgrowth where 

 the zygote is formed. The nuclear behavior in the zygote has not 

 yet been made entirely clear. The present evidence suggests that 



- Basidiobolus by some is placed in a distinct family. 



