1917] SAW YER—PHOLIOTA 213 
an imbedding material obviates the difficulty sometimes met with 
in the use of paraffin, that delicate structures may be deformed or 
dislocated by the heat of the oven or in spreading the paraffin 
ribbons. Furthermore, the cutting of thicker sections, with a 
sliding stroke, offers little chance for the displacement of structures, 
which might happen in cutting thin paraffin sections. I mention 
these points because some might suspect that the tearing away of 
the ground tissue below the hymenophore, as shown in the following 
figures, might be due to manipulation of the tissue, but such is not 
the case. 
Fig. 16 represents a section near the margin of the pileus; the 
hyphae of the hymenophore are growing down in little tufts, and 
at this time present a very loose, uneven surface. A considerable 
number of hyphae from the ground tissue below may be seen 
spanning the prelamellar cavity and united indiscriminately with 
the downward growing tufts of the hymenophore and. with the 
hyphae in the spaces between them. 
In fig. 17, from a section a little nearer the stem, Sia. ioe 
ophore on either side of the sectio presents the same loose, uneven 
surface as in the preceding figure; but in the middle the hyphae 
have enlarged at the tips and become blunt, and the ends have ~ 
grown down to form an even surface, the palisade, from which the — ae 
_ ground tissue is almost entirely broken away. ‘The reason that the — 
Palisade is in the middle of ped ete with undifferentiated tissue | 
on either side, i: dil 
sections, in pa 
y hyrecnaphore in t the middle of the s¢ 
is in the form of a cece ar around the stem | apex, so that ang en 
oe 
