PEZIZALES 



331 



closely related genus, with reticulate spores, Ruhlandiella berolinensis 

 and R. hesperia, the paraphyses form a gelatinous epithecium which is 

 persistent at maturity, while the hypothecium is poorly developed. 



The highest member of this series is Mycogalopsis retinospora (G jura- 

 Sin, 1925) which superficially is very close to Ruhlandiella and perhaps 

 should be referred to that genus. Here the hymenium is covered with 

 a layer of plectenchyma until maturity, suggesting the conditions found 

 in the Tuberales. The presence of a thin, more or less evanescent subic- 

 ulum (also found in Ruhlandiella) and the well-developed stalk suggest 

 their relationship to the Sphaerosoma group, while the breaking away of 



Fig. 219. — Sphaerosoma fuscescens. 1. Section through a very young fructification. 2. 

 Diagrammatic section of an old fructification. (1 X 67, 2 X 4; after Rouppcrt, 1909.) 



the covering of the apothecium, leaving a dusty mass of yellow spores, 

 suggests conditions seen in Myriangium. 



The ascus stroma develops rapidly on rabbit dung, maturing in about 

 a week. Three to six, three- to four-nucleate ascogonia arise at a point 

 on the subiculum, grow perpendicular to it and are abjointed. No 

 antheridium was observed. The ascogonia are soon surrounded by a 

 thin peridium developed from neighboring hyphae. Ascogenous hyphae 

 develop from the ascogonia forming asci directly on the tips of the 

 branches while the paraphyses develop from the cells immediately below 

 the ascogonia. Nuclear fusion in the ascus and subsequent spore forma- 

 tion is normal. ■ 



Thus in this family we have a transition from a simple hyphal subic- 

 ulum of unlimited growth and a gymnocarpous formation of the hymenium 

 to a highly developed, more or less tuberous ascocarp, with angiocarpous 



