GASTEROMYCETES 



481 



sponds to the volva of the Clathraceae), the pseudoparenchyma layer P, a 

 thin, tough, periclinal, fibrous layer F, and the collenchyma layer C. The 

 outer cells of the collenchyma layer elongate radially, become prismatic 

 and assume a peculiar palisade structure; the innermost layer next the 

 gleba consists of large spherical cells, called cystidia by earlier writers 

 but from their cytology probably basidia. At the top of the fructifica- 

 tion the peridium is weaker; there it is chiefly composed of isodiametric 

 lis. 



4 2 3 



Fia. 306. — Sphaerobolus stellatus. 1. Median section of young hyphal strand with 

 fundament of fructification. OR, outer rind; UR, under rind; GR, rind layer of tissue 

 knot; JR, inner rind of gel; GF, ground tissue of tissue knot; FA, fundament of fructifica- 

 tion. 2-4. Diagrams showing structure of fructification and discharge of gleba. (1 after 

 Pillay, 1923; 2-4 after E. Fischer, 1884.) 



The gleba *S develops rapidly. The nine-spored basidia, which soon 

 disintegrate, are formed in regular nests so that by the time the collen- 

 chyma has differentiated, they have collapsed. Further, the hyphae, 

 which form the trama collapse and the gleba becomes a slimy mass in 

 which are imbedded the spores, and gemmae. In youth the spores 

 are uninucleate but soon become binucleate. 



At maturity the isodiametric zone of the collenchyma layer splits 

 periclinally, so that the gleba, surrounded by the inner and the proximal 

 portion of the collenchyma, separates from the remaining peridium. 

 Because of the stronger surface growth of the collenchyma layer, this 

 splits, tears stellately at the top and slowly bends outwards, exposing the 



