334 A TEXTBOOK OF THEORETICAL BOTANY 



aggregated together into thick strands or rhizomorphs, which may be 

 traced for considerable distances from the fructification. The latter structure 

 begins as a little ball of hyphae at the end of a rhizomorph. In this two zones 

 are differentiated, an outer rind, the exoperidium, which is continuous 



Fig. 328. — Phallus impiidicus. Left, young fruiting body in 

 the egg stage, and on right a mature fruiting body with 

 exposed gleba. 



with the cortex of the rhizomorph, and a central portion, the columella, 

 w^hich is continuous with the core of the rhizomorph. The tissue of the 

 rind is very loose, and the hyphae at the head of the columella radiate out 

 fanwise to make a sort of sheaf-like head, in which most of the development 

 takes place. It expands greatly, and its outer layer gelatinizes and forms 

 what is known as the volva jelly, which is conspicuous in the later stages of 

 development. The inner portion forms an axial column, continued down- 

 wards into the columella, and a rather dense mantle around it (Fig. 329). 

 This mantle, which forms a dome-like covering to the axial column differ- 

 entiates again into a solid outer zone and a loose intermediate zone of radiating 

 hyphae. The inner edge of the onter zone now produces a palisade layer of 

 cells which becomes arched into irregular folds and pads, and this is the 



