346 



COMPARATIVE MORPHOLOGY OF FUNGI 



markedly differentiated (Fig. 230), and raises the fruiting disc over the 

 substrate and finally, in Macropodia of the Helvellaceae, reaches a height 

 of 2 cm. We will follow this line of development further. 



In the hypogaeous series, on the other hand, the habitat of fructifica- 

 tions affects their morphological form. The fructifications of many 

 Pezizaceae occur mainly on the earth from which they break forth at 

 maturity. If one now imagines a fructification of this type always 

 covered by the earth, so that the periphery arches over to a hollow sphere, 

 one will have an idea of the structure such as is given for Genea (Fig. 242, 

 4) in the following order; a hollow, partially folded knob which is covered 

 outside by a verrucose or short, tomentose rind and inside by continuous 

 hymenium. 



Fig. 230. — Aleuria sylvestris. Young and mature fructifications. (After Seaver, 1915.) 



If one now imagines that the hymenium undergoes a marked lateral 

 expansion and hence arches into the cavity of the sphere in folds and 

 pads, one has a further developmental stage, to which Sarcosphcera (Sep- 

 ultaria) belongs. In case the fructifications of this genus are formed 

 directly under the surface of the soil so that they can break through, their 

 tops may open lobately. If the layer of earth is too f thick, they remain 

 closed except for a small invisible opening, and then externally resemble 

 truffles. 



Finally, if one imagines these archings of the hymenophore so 

 developed that at maturity the folds and indentations fill the whole 

 cavity of the fructifications, we have Geopora, which belongs with the 

 Tuberales as well as the Pezizales. Hence we will return again to this 

 hypogaeous series in the Tuberales (E. Fischer, 1898, 1908; Gilkey, 1916). 



Helvellaceae. — The last family of the Pezizales to be here discussed 

 connects directly to the stipitate Pezizaceae, in Macropodia. By a 



