BOTANICAL GAZETTE 



[JULY 



and basidia in practically mature condition are shown in figs. 45, 

 46, 49, and in text fig. 6. The young basidia and cystidia, and 



the filaments which bear them, are 

 constantly binucleate, as are the other 

 cells of the young hymenophore, and 

 in fact all parts of the young basid- 

 iocarp. The nuclei in the cystidia 

 never fuse, and older cystidia lose 

 their nuclei by degeneration. The 

 cystidia are at all times much vacuo- 

 late and with scanty cytoplasm, while 

 the basidia and paraphyses are filled 

 with dense protoplasm. Very com- 

 monly the mature cystidium has a 

 mucous cap (fig. 49), thus suggesting 

 a possible excretory function, but this 

 is not a constant characteristic. 



Fig. 6. — Detail of portion of gill 

 shown in figs. 46 and 49, showing 

 cystidia, basidia, paraphyses, and 

 ultimate development of down- 

 ward outgrowths from subhyme- 

 nium (internal cystidia) . 



SURFACE CHARACTERS 



As was noted in the description 

 of the youngest stages of the fruit 

 body, the outer portion of the pileus is made up of h^q^hae 

 which radiate in a fanlike manner. As the development proceeds 

 these hyphae become closely compacted (figs. 32; 33), but for some 

 time retain this definite arrangement. The outer cells of this 

 layer soon enlarge and appear as a uniform palisade layer, as shown 

 in fig. 40, which is a higher magnification of the surface of the 

 fruit body shown in fig. 19. The filaments making up the interior 

 of the pileus branch and become much interwoven. As the pileus 

 expands the cells forming the uniform palisade layer enlarge, giving 

 the characteristic structure to the surface of the mature pileus 

 (fig. 41). Structurally these cells are binucleate, and in origin 

 seem to be homologous to the cystidia on the surface of the 

 gills. These cells, even from youngest stages, are filled with a 

 yellow granular content, however, and give to the pileus its 

 characteristic color. 



