CHAPTER V.—COMPARATIVE REVIEW.—GASTROMYCETES. zıı 
distinguished from other groups by the capillitium between the masses of spore-dust 
in the ripe sporophore. 
It has been already said that the peridium of the Lycoperdaceae is often of 
considerable thickness and is much differentiated at ihe time of the formation of the 
spores. The most important differentiation, which recurs in a variety of forms in the 
different species, is the separation into an inner layer directly enclosing the gleba, 
and an outer one which opens in different ways and becomes detached from the inner, 
the zuner and outer pertdium of authors. The genus Geaster supplies excellent 
examples of this. In Batarrea after the spores have ripened an axile strand of 
tissue, beneath the middle of the inner peridium about a centimetre in thickness, 
developes into a stout stipe, which may be as much as 2 decimetres in length and 
raises the closed inner peridium above the outer which has opened irregularly. 
The genus Scleroderma agrees in the structure of its sporophore up to the 
formation of the spores with the Lycoperdaceae and Hymenogastreae, especially with 
those in which the chambers of the gleba are filled with a tangled mass of hymenial 
elements. Here too the hymenial tissue is dissolved and desiccation takes place 
when the spores are fully ripe; the chambers remain filled with the dry powdery 
masses of spores and the trama is disorganised, but persists as a dry fragile net- 
work in which the original structure is indistinctly shown. No capillitium with its 
characteristic structure is formed, at least not in the species examined by Tulasne 
and myself. It is evident therefore that Scleroderma is intermediate between the 
Lycoperdaceae and Hymenogastreae. 
As regards the mode in which the Lycoperdaceae and Scleroderma form their 
spores, the question raised by Berkeley in 18411, whether the spores always attain 
their full development and maturity while still attached to the basidia, or whether they 
do not mature till after the disappearance of the constituents of the hymenium and at 
the expense of a portion of the products of disorganisation, as is the case in 
Elaphomyces (see page 97), requires further investigation; Sorokin has recently 
pronounced in favour of the second alternative. 
3. If we imagine the entire number of the chambers in the compound sporophore 
in Fig. 141 reduced to from twenty to thirty and each chamber comparatively large 
regularly lenticular in shape and furnished with very thick walls, we get the plan of 
the young sporophore in Nidularia. When ripe the outer wall-layers of the peridium, 
except at the apex, and those which directly surround the cavity of each chamber 
with its hymenium, persist as thick membranes consisting of many layers. The tissue 
between these persistent layers becomes transformed into a jelly, and the wall of the 
peridium also disappears over the entire surface of the apex. The ripe sporophore 
therefore is an open bowl, in which the separate chambers as closed lenticular 
receptacles (Zeridiola) are imbedded in mucilage and are at length set at liberty by 
its disappearance. The genera Crucibulum and Cyathus exhibit the same 
phenomena with a still greater diminution in the number of the chambers and an 
augmentation of the transitory gelatinous tissue-mass; there is also a further 
complication, inasmuch as each peridiolum remains attached inside to the persistent 
wall of the peridium by a strand of tissue of complicated structure, which is likewise 

} Annals and Magaz. Nat. Hist. VI, p. 431. 
