Nov., 1922] LEVINE LAMELLAE IN AGARICUS CAMPESTRIS 
Figure 52, Plate XXIX, represents a longitudinal tangential section of 
a young button in which a number of gill Anlagen are shown. The margins 
of these young gills are in connection with the tissue below them, and in 
the center or oldest part of the section gill cavities are already formed. 
While this is a microphotograph of a plant that died very early in its devel- 
opment, similar stages were observed in the living buttons. In the un- 
stained sections of young living buttons the gill chambers are wider near 
the stipe region. The palisade cells which cover the upper surface of the 
gill chambers are small cells which are not markedly oriented as we find 
them in the Coprinus species. The trama primordium is very difficult to 
distinguish in unstained material, yet it has been made out clearly to 
consist of a narrow band of tissue which is composed of cylindrical cells, 
which are continuous with the cells in the stipe below and in the pileus 
above. In the preparation of the dead plant as shown in the above-men- 
tioned figure, the palisade cells do not stain strongly, but a thin, pale 
violet stain is present between the compact mass of cells of which it is 
composed. The trama walls stain heavily. The fundamental tissue below 
the gill cavities consists of a loose plectenchyma which occasionally shows 
a disintegrating nucleus. 
In an older stage of a button, also slightly larger, shown in the fresh 
carpophores, the tramal elements are in close connection and continuous 
with the hyphae of the fundamental tissue of the stipe and pileus. The 
gill primordia are considerably larger, while the palisade cells are longer 
and have become more numerous but maintain the same shape. In a fixed 
button that had turned brown at the same age and size, shown in figure 53, 
the tramal elements are seen clearly in connection with the stipe and pilear 
tissue. The triangular arch of the gill cavity is covered by palisade cells 
which stain faintly. The highly granular appearance of the fundamental 
tissue below the gill rudiment is due to crystal deposits in the cells. 
A median and tangential section of another dead carpophore (fig. 55), 
of the same size but fixed two days after the one shown in figure 53, shows 
that the palisade cells have largely disappeared and can only occasionally 
be recognized around the broad and deeply staining tramal tissue. The 
hyphae of the fundamental tissue are deeply stained also, and, as in the 
living carpophores of this age, long strands of hyphae can be traced directly 
into the trama of the young gill rudiments. In the tangential section 
shown in figure 54 a number of the gills to the right are disconnected from 
the fundamental tissue below them. This is due to the splitting and 
collapse of the fundamental tissue as indicated by the more compact plec- 
tenchyma of hyphae shown at B. This figure is comparable with the figures 
of Atkinson (1906, figs. 12, 19, 32-38) and Sawyer (1917&, fig. 37); these 
authors, however, failed to recognize that the material they were studying 
was dead when fixed as evidenced by the disappearance of the palisade 
cells and the apparent continuity of the tissue of the rudimentary gills 
