CHAPTER V. COMPARATIVE REVIEW. GASTROMFCETES. 31! 



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 the 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 inner and outer peridium 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 I84I 1 , 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 (peridiola) 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 



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



