TAXONOMY 
27 5 
“bricks” are put in the horse manure bed only after the heat has 
first disappeared. The beds are then watered well and in a short 
time the sporophores or fruiting bodies of the fungus spring up. 
The mycelium or vegetative body of Agaricus which develops 
in the soil from spores (basidiospores) is white and thready. On this 
mycelium develops little buttons, first about the size of a pin head, 
becoming later pea size and then assuming a pear-shaped form. At 
this stage the sporophore consists of a cylindrical solid stipe or stalk 
and a pileus or cap. The border of the pileus is joined to the stipe 
Fig. 144. —Meadow mushroom (Agaricus campestris L.). A, view showing 
under side of pileus; g, gills; a, annulus, or remains of the veil attached to’ a the 
stipe; B, side view; s, stipe; a, annulus; p, margin of pileus, showing at intervals 
the remains of the veil. (Gager, after W. A. Murrill .) 
by means of a “ partial veil” Within this veil is found a circular 
cavity, into which the gills grow. At first the stipe grows faster than 
the rest of the fruiting body. The pileus expands transversely and 
the gills keep pace. After a while the veil ruptures, leaving a portion 
attached to the stipe. This constitutes the annulus or ring (true 
annulus). The hyphae in the pileus form the Tela contexta. If we 
make a section through a gill, the hyphae are seen to run longitudi¬ 
nally. The central part is called the trama\ next and outside trama 
is the sub-hymeniunr, next, hymenium, consisting of basidia (hence a 
