THE FUNGI 261 
(@) The structure of the gills, as shown in a mushroom split 
lengthwise through the stem and cap and examined with the mag- 
nifying glass. 
Cut off the stalk of a well-expanded mushroom or toadstool close 
to the cap and place the latter, gills down, on a sheet of paper. If 
the gills are light-colored use black paper, if dark- 
colored, white paper. After some hours lift off 
the cap and examine the print left by the spores. 
(e) The extent of the mycelium as far as it 
can be traced in the earth or other substratum 
on which mushrooms or toad- 
stools are growing. 
338. Minute Structure of the ( 
Gills. — Cut thin sections of 
one of the gills at right angles 
to its flat surface. Mount and 
examine first with m.p. and 
then with h.p. If spores are 
not shown, as in Fig. 187, re- 
peat with part of a gill from 
another mushroom. Note: A 
(a) The general structure 
of the gill, the interior consist- 
i f loosely interwoven hy- 
= : dth y t 1 fruiti y A, slightly magnified. B, one of the parts 
paean wae oe aut mg of A, more magnified; hym, hymenium; 
portion, the hymenium, consist- _h, central layer. 
ing of ends of hyphe definitely 
arranged. What is their position relative to the surface of the gill? 
(b) The basidia, or club-shaped tips of spore-bearing hyphe. 
(c) The sterigmata, or short stalks on the basidia, each sterigma, 
bearing a spore. 
.(d) The size, shape, and color of the spores and the number borne 
by each basidium. : 
(e) The sterile filaments parallel to the basidia and lying between 
them. 
hym h 
W 
WW’ 
< 
s 
= 
Mi ( 
‘\ 
Mf N 
NAN 
H(t 
i 
Fic. 186. Portions of Gills of a 
Fungus (Agaricus). 
339. Discussion. — The gill fungi (including most of the 
toadstools and mushrooms) are some of them saprophytic 
