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A. W. BLIZZARD 
immediately below the margin of the pileus. This shows the palisade layer which is 
formed by the gradual increase of primordial elements by intercalary growth. At 
the same time the cellular elements, which result in a compact layer. X 300. 
Fig. 45. A cross-section similar to the above only of a slightly older stage. 
It shows the first appearance of gill salients, which are the outfolding of the palisade 
layer. Subadjacent hyphae grow into this fold, and by elongation force the salient 
outward, at the same time branching in a corymbose manner, new elements are added. 
X 300- 
Fig. 46. A cross-section of the pileus which shows further growth of the gill 
salients. The hyphae that force their way down into the salients from the pileus 
elements do not stain so deeply and are easily distinguished. They form the 
trama of the lamellae. X 300. 
Fig. 47. A cross-section of a little older stage than the preceding figure. 
This shows the apical development of the gill by which the lamellae increase in 
thickness. 
Plate IX. 
Figs. 48-63. Clitopilus novehoracensis. 
Fig. 48. A median longitudinal section, showing the homogeneous weft of 
slender, interwoven hyphae. The peripheral hyphae end at varying distances from 
the tip, so that the surface slants gradually from the base to the apex. X 20. 
Fig. 49. A median longitudinal section, showing the flaring of the hyphae 
at the apex which serves as a line of demarcation between the pileus and stipe 
primordia. On the surface of the stipe primordium is a very narrow zone of tangled 
hyphae which stain more deeply. This is composed of the ends of hyphae which 
project farther than those that compose the weft. X 20. 
Figs. 50-54. Median longitudinal sections, showing older stages of develop- 
ment. The marginal hyphae by epinastic growth turn downward, forming the 
annular groove on whose surface is the hymenophore primordium. 
Fig. 55. A median longitudinal section of a more mature plant, showing its 
general habit. The margin turns in and upward towards the gills. The marginal 
hyphae extend outward as a loose weft and span the space between the pileus margin 
and gills. At this stage it has the function of a marginal veil. X 13. 
Fig. 56. A tangential section through the pileus near the stipe, showing the 
palisade layer. X 20. 
Fig. 57. An oblique transection through the margin of the pileus and upper 
part of the stipe. The cavity within represents the annular groove. On the surface 
of the stipe the palisade layer has been thrown into folds. These folds are the gill 
salients. Thus the origin of the primary gills is on the stipe. X 20. 
Fig. 58. A tangential section of a young pileus, showing the origin of the 
primary gills as they extend from the stipe on the lower surface of the pileus toward 
the pileus margin. X 20. 
Fig. 59. A slightly oblique transverse section through the pileus margin 
and upper part of the stipe, showing the origin of the secondary lamellae between 
the primary gills. The primary gills appear as "bars," connecting the pileus and 
stipe. X 20. 
Fig. 60. A tangential section through the pileus, showing the decurrency of 
the gills; also the incurving of the pileus margin. X 20. 
