CHAPTER V.—COMPARATIVE REVIEW.—GASTROMYCETES. 327 
The peridia of Tulostoma are formed, according to Schröter, on subterranean 
mycelial strands, which are flat sclerotia and may be 6 mm. in breadth; they are 
probably shoots from these sclerotia, and are round bodies about 4mm. in diameter 
composed of a uniform weft of primordial hyphae; the superficial ramifications 
of the hyphae form a floccose envelope which attaches itself to the grains of sand 
in the surrounding soil. The differentiation into gleba and peridium may be ob- 
served when the compound sporophore has reached the size of 6-8 mm. The peridium 
is a relatively thick hyphal layer entirely surrounding the gleba and having a conical 
thickening at the upper end as the primordium of the papilla which afterwards 
appears at the opening of the peridium; there is also a broadly obconical thickening 
below. The peridium separates further into an axile cylinder situated beneath the 
middle of the gleba and into a part which surrounds the cylinder like a sheath. The 
cylinder elongates at maturity into the cylindrical stipe which attains a length of 3-6 cm. 
and raises the peridium above the ground; the elongation causes the sheath to 
separate by a transverse fissure into a lower portion, the base of the stipe, and an 
upper, which surrounds the upper end of the stipe, according to Vittadini (see Fig. 160), 
and both portions then dry up. There is no separation into inner and outer wall 
in the peridium. The gleba is at first a reniform body which afterwards becomes 
spherical in form, and is distinguished by the absence of chambers. It is formed 
of a uniform tangled mass of hyphae about 
2 in thickness, the branches of which pro- 
duce the strangely-shaped basidia described 
above on page 309. The abscision of the 
spores is over and the basidia deliquesce 
before the stipe begins to enlarge ; then the 
spore-membranes turn brown, the - process 
advancing, according to Schröter, from the 
centre towards the circumference of the gleba. 
A large number of the hyphae of the gleba 
begin to develope shortly before the disap- 
pearance of the basidia into the close net-work 
of stout threads, which form the capillitium Gute 1 20 tere A 4 
and grow all over the wall of the peridium, as stipe, the gleba at the apex beginning to assume the 
in Geaster hygrometricus. ne Avene Manes En 
Polysaccum is another strange object and 
deserves further examination; it is a large 
somewhat elongated or club-shaped body which has chambers throughout except 
in the thin outermost fibrillose layer; a few concentric layers of chambers in the 
periphery are smaller and sterile and together represent a peridium; the chambers 
in the interior which are polyhedric, and may be as large as a pea at maturity, 
are about I mm. in diameter when the spores begin to be formed, and are filled 
with hyphae closely woven together into a hymenial coil and either sterile or pro- 
ducing basidia. These hyphae have very soft gelatinous membranes, and the whole 
coil may be removed uninjured from the brown trama. The chambers at maturity 
contain only a chocolate-brown spore-powder, the tramal laminae with the peridium 
being disorganised and desiccated and crumbling to pieces. No capillitium is formed. 
The formation of the chambers begins at the apex and advances, very slowly as it 
would appear, towards the base of the peridium which is sunk deep in the sandy 
soil. Specimens are found in which the upper half is quite ripe while in the lower 
all stages of the development may appear in unbroken succession one above another. 
The earlier states are not known. The same thing appears to occur in Berkeley’s 
Phellorinia. The agreement with Scleroderma is evident; it is possible that Poly- 
saccum, Phellorinia, Scleroderma, and Melanogaster form a distinct group marked by 
the hymenial coil which fills the chambers. 

