iqiq] walker— PLUTEUS AND TUBARIA 13 



ward into the annular prelamellar chamber below the palisade 

 region. The first folding takes place near the stipe, as can be seen 

 in the series of tangential sections shown. The details of figs. 60 

 and 62 are shown in figs. 83 and 86. The young gill salients thus 

 formed by the folding of the palisade layer, along with downward 

 growth in radial areas, develop rapidly, and as development pro- 

 gresses the longest gill salients are found next to the stipe and adnate 

 to it (figs. 64-68). The folding continues outward so that near 

 the margin we find a uniform or level palisade layer during the 

 period of growth. Fig. 91 is a higher magnification of the 

 hymenium shown in fig. 67. In this series, as well as in the basidio- 

 carp illustrated in figs. 69-73, ^ strongly epinastic and horizontal 

 development is observable in the pileus, and the margin of the 

 pileus becomes strongly incurved. As can be seen by the tangential 

 sections, the development of the gills continues to be centrifugal, 

 and the level palisade layer is to be found on the incurving edge of 

 the pileus. The structure of the gills at this age can be seen in 

 figs. 87 and 88, higher magnifications of fig. 69. The trama is 

 composed of somewhat parallel filaments that branch sparingly until 

 the subhymenium is reached, and then branch repeatedly to give 

 rise to the young basidia and paraphyses. Fig. 89 shows the 

 same condition in tangential, sections in a somewhat older fruit 

 body. Figs. 74-76 show a fruit body nearing maturitv. The 

 broad attachment of the gills to the stipe, and the general triangular 

 shape of the gills characteristic of this genus, are also shown in 

 the median section (fig. 74), and the attachment of the gills is also 

 clearly shown in fig. 77, a horizontal section through the pileus of a 

 fruit body nearing maturity. As the epinastic development of the 

 pileus continues, the margin of the pileus becomes more and more 

 inturned. This strong incurving of the margin of the pileus results 

 in sections similar to the ones shown in figs. 75 and 76, where the 

 section passes through the incurved margin of the pileus as well as 

 through the upper portion. The stalls or pigeonholes thus formed 

 might lead one to an erroneous idea as to the origin of the gills if 

 their development had not been traced through the earlier stages. 

 The secondary gills originate in the same manner as the primary 

 gills, but at varying distances from the stipe. Sections of some of 



