19IS-] DEVELOPMENT OF AGARICUS RODMANI. 335 



tissue clothing the stem fundament, as shown by the clear line 

 between the two. This indicates that the portion of the hymeno- 

 phore on the upper surface of the stem projected by growth slightly 

 above the level of the stem surface, or above that of the ground 

 tissue. In Fig. 34 the distinct boundary line of the more compact 

 tissue shows, but it is in contact with the ground issue below since 

 this section did not pass outside of the junction of stem and pileus 

 fundaments. In Fig. 35 a few of the gills on either side of the 

 middle are free from the ground tissue below. Outside of this on 

 either side (the middle zone between stem and pileus margin) a 

 number of the gills are attached to the ground tissue pressed up 

 against them by the involute pileus margin. On either side of these 

 areas, i. e., near the margin of the pileus, the gills are free. 



Fig. 36 is from a section in the region indicated by line 5 in 

 diagram 7. The middle of the section, according to line 5, would 

 pass through the space of the annular cavity near the stem which 

 has not been filled by the upward crowding of the ground tissue. 

 The margin of the gills here should therefore be free from the 

 ground tissue below. This is shown to be the case in Fig. 36, for 

 the gills over the middle portion of the figure (which are near the 

 stem). On either side of this area, however, the section passes 

 through the zone where the ground tissue is crowded up against the 

 gills, while toward the margin of the pileus the gills are again free 

 from the ground tissue. 



Figs. 37 and 38 are from sections in the region of lines 6 and 7 

 respectively, of diagram 7. Both sections are thus " tangents " 

 through the region where the ground tissue in contact with the 

 middle zone of the gills would be continuous and of considerable 

 extent, but the area in the region of line 6 would be of greater extent 

 than that in the region of line 7. This corresponds with the situa- 

 tion shown in Figs. 37 and 38, while toward the margin of the pileus 

 on either side the gills are free. Figs. 39 and 40 are from the region 

 of lines 8 and 9. These pass through the portion of the annular 

 cavity between the margin of the pileus and the ground tissue 

 crowded up against the middle region of the hymenophore. The 

 gills therefore would not be in contact with the ground tissue below. 

 In Figs. 39 and 40, however, it is clear that on either side the gills 



