CHAPTER V.—COMPARATIVE REVIEW.—GASTROMYCETES. 323 
two outer layers and of the inner wall of the peridium, so far as it surrounds the gleba, 
advances farz fassu with the enlargement of the stipe. On the other hand, the tissue 
in the cone and in the portion of the central column beneath the gleba diminishes 
in proportion as the stipe enlarges, till at length in Ph. caninus (Fig. 153 y) it is only 
a thin white membrane; in Ph. impudicus it remains of larger size underneath the 
gleba, forming a cup-shaped basal piece which supports the lower extremity of the 
stipe (Fig. 154) ; in the cone it stretches into a thin white membrane, as in the other 
species. The gleba, in which the formation of spores is completed or nearly completed 
during the expansion of the stipe, dilates in Ph. caninus into a thin conical cap 
covering the upper part of the stipe close beneath the extreme summit; in Ph. impudicus 
it diminishes less in thickness in proportion to the extension of its surface, and the 
hyphae of the trama even manifest an active growth by the expansion of their cells. 
No change in structure worth mentioning here occurs in the parts surrounding the 
stipe during the time that it is enlarging beyond an evident increase in the size of the 
hyphae. The cells of the parenchyma of the stipe itself continue thin-walled and 
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FIG. 154. Phallus impudicus. A nearly mature 
FIG. 153. Phallus caninus. Young sporophore partly attached example before the elongation of the stipe, in median 
to the mycelium 7 in median longitudinal section and natural size. longitudinal section ; 2 mycelium, a outer, z inner 
Succession of stages of development according to the letters u—y. wall, g gelatinous layer of the peridium, s¢ stipe, % 
y a specimen not fully grown but with ripe spores ; @ the outer wall, its cavity filled with mucilage, ¢ lower margin of the 
“the inner wall, g the gelatinous layer of the peridium, 2 the basal pileus, sp gleba, » the cup-shaped basal portion, 
portion, & the cone, s the stipe, rd the gleba. x the spot where the peridium is ruptured by the 
elongation of the stipe. After Sachs, Two-thirds of 
natural size. 
filled with a watery fluid. At length all growth by expansion of cells already formed 
or by the formation of new ones comes to an end in all parts, and then comes a sudden 
increase in the length of the stipe, which thrusts the gleba which is attached to its 
summit against the apex of the peridium and bursting through it raises the gleba 
high above it. The elongation is brought about simply by the raising and smoothing 
out of the folds in the plates of parenchyma in the wall of the stipe, like the folds in 
a paper hand-lantern, to repeat the comparison of the old botanist Schäffer, till 
the length of the chambers is at least equal to the breadth; the elongation of the 
chambers is caused by accumulation of air within them and their consequent inflation. 
The gelatinous felt which fills them at first is torn up and disappears, and the axile 
gelatinous strand is also torn and replaced by air. This process takes place simul- 
taneously at all points in Ph. impudicus; in Ph. caninus it begins above and advances 
slowly towards the base. The elongation of the stipe causes the inner peridium 
of Ph. caninus to separate into two parts by an annular fissure beneath the gleba; 
the upper portion with the remains of the cone is carried upwards while the lower 
Y 2 
