CHAPTER V. COMPARATIVE REVIEW. GASTROMYCETES. 327 



The peridia of Tulostoma are formed, according to Schroter, 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 4 mm. 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 /i 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 Schroter, 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 FlG - Ifo - Tulostttna mammon. Median longi. 



. f. tudinal section, a before the elongation of the young 



and grOW all OVer the Wall Of the peridium, as stipe, the gleba at the apex beginning to assume the 



. , . dark colour of ripeness, t after the stipe has begun to 



in GeaSter hygrOmetriCUS. elongate. After Vittadini. Natural size. 



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 white 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. 



