492 



COMPARATIVE MORPHOLOGY OF FUNGI 



and nurse tissue, has all been used up, the whole gleba gelifies and forms a 

 thin, collapsed lining of the peridium, leaving a large, empty space in the 

 middle. The mycelium is wholly binucleate. As usual, fusion of the 

 dicaryon occurs in the basidium. The fusion nucleus forms six nuclei 



which migrate into the spores and divide 

 once, producing binucleate basidiospores. 

 In Jaczewskia, a rare genus found 

 once in Russia and once in British 

 Columbia, the fructification consists of a 

 gleba supported on a large sterile base 

 which is slightly prolonged below into 

 a short stipe. Several primary tramal 

 plates grow upward from this base and 

 give rise to the anastomosing secondary 

 tramal plates (Mattirolo, 1912; C. W. 

 Dodge unpublished observations). 

 In Hysterangium the well-developed columella is persistent to maturity. 

 In H. nephriticum the sterile base is prominent and persistent, with the 

 columella scarcely more than a branch rising from it. As we saw in 

 Dendrogaster, the columella becomes increasingly well developed as the 

 sterile base disappears. H. inflatum is also reminiscent of Dendrogaster, 



Fig. 314. — Hysterangium clath- 

 roides. Section of mature fructifica- 

 tion. ( X 2; after E. Fischer, 1900.) 





-i-S-Z-str 



^'■>KV:^r 





Vi&" 



Fig. 315. — Hysterangium clathroides. 1, 3. Median sections of young fructifications. 

 2. Section of periphery of young fructification. (1 X 10; 2 X 7; 3 X 270; after Reh- 

 steiner, 1892.) Rhopalogaster transversarium. 4. Diagrammatic section of young fructi- 

 fication. Gl. Km, gleba cavities; Tr, tramal plates; Per, peridium; Z. str, columella; 

 Bas, basidial fundaments. ( X 10; after Johnston, 1903.) 



with its inflated, gelatinous sheath about the spore. In this group, the 

 peridium, although of different texture from that of the trama, is homo- 

 geneous and composed of slender parallel hyphae. From forms like these, 

 there is a series to those with a highly developed columella and a peridium 

 of coarse, thick-walled hyphae, and, finally, a well-developed pseudo- 



