114 



COMPARATIVE MORPHOLOGY OF FUNGI 



the sporangia and zygospores have not been experimentally determined. 

 Endogone is saprophytic and generally subterranean, while Sphaerocreas, 

 Sclerocystis and Glaziella are lignicolous. The thallus consists of 

 multinucleate hyphae often anastomosing and becoming septate in age. 

 The sporangia, formed in special fructifications (sporangiocarps), 

 are known only in Endogone reniformis and E. malleola. These consist 

 of a thick, solid, whitish-yellow pseudoparenchyma (Fig. 68, 1) which 

 may attain a considerable size, up to 2 cm., and at times possesses a 

 definite form (e.g., reniform in E. reniformis). In the rind layer or in 

 special sporiferous hyphae radiating in all directions, terminal or inter- 

 calary Mucoraceous sporangia are formed. As in Mortierella, their 

 contents split into regular portions and finally flatten polyhedrally from 



Fig. 68. — Endogone malleola. 1. Longitudinal section of a sporangial fructification. 

 2. Young sporangium. 3. Section of mature sporangium. 4. Mature sporangium. 

 Endogone reniformis. 5. Mature sporangium. Endogone fasciculata. 6. Young chlamy- 

 dospore. 7. Fascicle of chalmydospores. Glaziella aurantiaca. 8. Hollow chlamydo- 

 sporic fructification. 9. Group of chlamydospores in ground tissue. (1 X 12; 2 to 6 X 

 370; 7 X 67; 8 reduced; 9 X 36; after Bucholtz, 1912, and Thaxter, 1922. 



lateral pressure (Fig. 68, 2 to 5). The spores germinate with one or 

 several germ tubes (Bucholtz, 1912; Thaxter, 1922; Walker, 1923). 



The zygospores are also united into fructifications and arise mostly 

 inside the whitish or yellowish tuberiform hyphal knots up to the size of 

 a hazelnut (Fig. 69, 9), which in some species contain latex organs. At 

 present the youngest known stage of these fructifications consists of a 

 comparatively thick tissue of ramose hyphae which at the periphery are 

 closely intertwined and form a sort of peridium. In the ground tissue, 

 there appear a large number of pairs of copulation branches whose 

 development proceeds approximately simultaneous throughout the 

 fructification. 



In the only species whose sexual reproduction is well known at present, 

 E. lactiflua (Bucholtz, 1911, 1912), the copulation branches arise mostly 



