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AMERICAN JOURNAL OF BOTANY 
[Vol. 9, 
The next space toward the center (b) with small radial lines represents the 
smooth, unoriented palisaded layer of hyphal cells which is followed by a 
region (c) of oriented palisaded cells, and this in turn by the older portion 
Diagrams i-6. i. Longitudinal tangential section of a fresh carpophore showing the 
young lamellae (a), attached to the fundamental tissue (5), and forming a number of inter- 
lamellar spaces (c). 2. Longitudinal tangential section of a fresh carpophore after having 
been fixed from 6 to 24 hours. The young lamellae (a) are torn away from the fundamental 
tissue {b), leaving a wide annular gill cavity (c). 3. Top view of a carpophore in the earliest 
stages of development ; the outermost space (a) represents fundamental and undifferentiated 
tissue; (b) smooth, unoriented, palisaded layer of hyphal cells; (c) oriented palisaded cells; 
(d) older portion of hymenophore primordium with gill cavities and gills; (e) stipe rudiment. 
4. Radial section of pileus showing three gills of different lengths. 5. Various widths of 
gills shown by vertical cross sections made at various distances. A, B, C, etc., from the stipe. 
6. Top view of carpophore showing secondary gills. 
of the hymenophore primordium (d), that is, where distinct gill cavities and 
gills are already formed. The inner space represents a portion of the stipe 
rudiment (e). The line A A represents a vertical tangential section shown 
in figure 77, cutting through and exposing two groups of palisaded cells at 
the tips of which we find the youngest stage of two gill cavities. The line 
E 
5 
