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P ras 
264 ue 6 tructural ue | Physiological Botany. = 
The receptacle varies greatly in its external form" he bs em 
the production of spores is almost always limited toa par- < 
ticular part, the Aymentum. Thus, for example, in the 
mushroom-shaped Fungi (Agaricini) the spores are formed _ 
only on delicate plates on the under side of the Azlews. 
In many cases the receptacle is naked ; in others the lower 
side of the pileus is covered with a membrane which is 
ruptured when near maturity (Fig. 392) (velum partiale or 
\ a =O ON ee Es, 
io ny, 4) 
Z Ly/) 
vy ox CG uy Legs | 
= ji ee 
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4 
\ 
Mi 
A> 
——s 
LFA 
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yy 
m ————. 
FG. 392.—Mushroom, Agaricus campestris; one young globular and two mature 
receptacles, a pileus; 4 lamellz ; c annulus (natural size). 
annulus); or often the pileus and stalk are both enveloped 
in such a membrane (ve/um universale), or occasionally both 
are present (Fig. 393 1). In the Phalloideze and Tuberacez, 
as Bovista and Zuber, the hymenium, to which the term 
gleba is also given in these cases, is distributed into 
chambers, and is found in simple or double sacs or recep- 
tacles, the pertaza (Fig. 394), enclosed on all sides. The 
Pyrenomycetes, finally, have small flask-shaped receptacles, 
