554 CLASS BASIDIOMYCETEAE 



Fig. 184. Lycoperdales, Family Geastraceae. Geastrum rufescens Pers. (Courtesy, 

 Coker and Couch: The Gasteromycetes of the Eastern United States and Canada, 

 Chapel Hill, Univ. North Carolina Press.) 



chief genus is Geastrum.^ In this genus the inner peridium remains intact 

 when the outer peridium sphts open. It is sessile or on a short stalk and 

 has a single apical ostiole. (Fig. 184.) In Myriostoma the inner peridium 

 stands upon several slender stalks and there are several to numerous 



ostioles. 



In the two foregoing genera the gleba is like that of the Lycoperdaceae, 

 made up of tramal tissue with numerous closed, basidium-lined hymenial 

 cavities. There is usually but not always a columella. Formerly included 

 in this family was Astraeus hygromelricus (Pers.) Morg., in which the 

 chief difference is the partial obliteration of the hymenial • cavities by 

 ingrowing tufts of basidia. The outer peridium is exceedingly hygro- 

 metric, opening out when moist, closing to almost the original position 

 when dry. Because of the difference in glebal structure Fischer (1899, 

 1933) placed this genus in Family Calostomataceae in the Order Sclero- 

 dermatales. In view of the fact that in the family Sphaerobolaceae both 

 types of gleba are present without even leading to the division of the 

 family it appears best to retain Astraeus in the Geastraceae. (Fig. 185 A.) 



The two remaining genera of the family were called by Fischer Geas- 

 teropsis and Trichaster, but Long (1945) pointed out that the former name 

 is not available nor is his own earlier name {Geasteroides, 1917) so that he 

 applied a new name Terroslella. This differs from Geastrum in the pos- 



1 In most publications and in the author's earlier book this genus is called 

 Geasler. Since, however, the international rules of botanical nomenclature designate 

 Persoon's Synopsis Methodica Fungorum (1801) as the basis for the nomenclature 

 of the Gasteromyceteae his name Geastrum must be used, not the name preferred by 

 later mycologists. 



