GASTEROMYCETES 



469 



cation. Subsequently, the hyphae of the surface of the cavities come 

 together into a hymenial palisade. By growth of the palisade, the tramal 

 plates become increasingly irregular and finally occupy most of the 

 gleba (Fig. 297, B). 



In some species, as R. luteolus, the trama tend to split, suggesting 

 conditions in Pisolithus in the Sclerodermataceae. In other species 

 there is differentiated, outside the ground tissue, a peridium which may be 



m0§m& 



Habit (natural size). 



Fig. 297. — Rhizopogon luteolus. A 

 fructification (X 14). C. Part of gleba (X450). Rhizopogon rubescens 

 section of young fructification ( X 28). (After Tulasne and Rchsteiner.) 



B. Portion of periphery of 

 D. Median 



evident only by the different character of the cells (swollen and irregular 

 in R. diplophloeus) or by different color and its sloughing off in spots, 

 giving a characteristic ragged appearance to the fructification, as in R. 

 pannosus and R. Briardi. 



Melanogaster variegatus is similar to R. rubescens in appearance, but its 

 spores are black instead of light yellow and its basidia are short, pyriform 

 and not arranged in compact hymenia. The latter character led some 



