454 BRITISH FUNGI 



Development taking place underground. Volva at first con- 

 tinuous, with a thick, gelatinous middle stratum ; spores very 

 minute, when mature immersed in a greenish mucilage, which is 

 elevated out of the volva on a long stem or receptacle. 



Phalloideacecc. 



Hymenogastrace^ 



The principal characteristics of the present group are the sub- 

 terranean habit, entire absence of a capillitium, gleba not becoming 

 resolved into a dry, powdery spore-mass at maturity, and the in- 

 dehiscent peridium. 



The species are, as a rule, more or less subglobose in form, and 

 vary in size in different species from a pea to that of a walnut. 

 The mycelium is usually copious, and often forms fleecy masses 

 spreading amongst vegetable humus at a slight distance from the 

 surface. In some species of Melanogaster, etc., the mycelium forms 

 long, spreading, cord-like strands which produce ascophores at 

 various points ; hence it is not unusual to meet with clusters of 

 ascophores of various ages and sizes in the same locality. 



The majority of species grow under trees, which suggests that 

 the mycelium may form mycorhiza on the roots of the trees, as 

 has been shown to be the case between the mycelium of species of 

 Elaphomyces and the roots of conifers. In many species there is 

 no obvious point of attachment, the mature ascophore lying per- 

 fectly free and unattached. In other species there is a more or less 

 distinctly marked sterile base, indicating the original point by 

 which the fungus was attached to the substratum. This sterile 

 base, shadowed in in the present family, becomes more highly 

 evolved and differentiated in some of the puff balls, etc., until it 

 eventually resolves itself into a differentiated stem, which in the 

 above-ground fungi is of use in elevating the spore-bearing portion 

 of the fungus, and thus facilitating the dispersion of the spores by 

 wind, etc. As usual in primitive or ancient types of fungi, the 

 spores are exceptionally large, coloured, and the surface of the wall 

 is frequently ornamented with a network of ridges, warts, spines 

 etc. The basidia are somewhat erratic in their mode of develop- 

 ment, producing a variable number of sterigmata, and have not 

 settled down to producing the stereotyped number of four, as is 

 usual in most of the agarics. No special provision is made for the 

 dispersion of the spores by the aid of physical agents, and appa- 

 rently the common mode of dispersion is through the ascophores 

 being eaten by animals ; and even here the arrangements for such 

 means of dispersion are not so highly differentiated as in the 

 Tuberacere or truffle family, where the majority of species possess 

 a penetrating smell, which indicates to animals, more especially 

 rodents, their whereabouts. 



None of the species, with one exception, are edible ; neither are 



