From Spore to Mushroom 
leaving a ragged edge to the cap, anda ring or annulus of veil 
around the stem. The gills of the Agaricus are not fastened to 
the stem, but are rounded off at 
the end near the stem, while 
others, between the long ones, 
extend from the edge of the cap 
only far enough toward the stem 
to fill up the angles formed by | 
the long gills. 
The surface of the gills is the 
fruiting portion of the mushroom. 
It is here that the spores are 
formed. 
The structure of the fungus 
plant up to this point has been 
similar throughout. A loose tangle 
Wh ¢ - 
A small portion of section of gill 
(highly magnified) 
Corn smut 
(2) Just outside of this loose 
mycelium, on either side, are layers 
of short cells (¢), which bear club- 
shaped bodies standing out over 
both surfaces of the gills (2). 
(3) Each club bears two slen- 
der processes (s#) at the free end, 
and each process bears a spore 
(sf). 
of threads underground formed the myce- 
lium—the food provider. A more closely 
matted tangle above ground formed the 
stem and cap and veil, and even the central 
part of the gill—the fruiting parts of the 
plant. 
On the surface of the gill a difference 
in structure is found, which will be clearly 
understood from a picture of a thin section 
cut across a gill. 
(1) The central portion of the gill is 
made by loosely tangled mycelium threads 
(ér) draping themselves in thin plates from 
the surface of 
the cap. 
Leaf rust on Hepatica triloba 
13 
