90 MORPHOLOGY 



(j) Hymenogastrales 



This group contains the simplest Gasteromycetes, and the name suggests char, 

 acters belonging to both Hymenomycetes and Gasteromycetes. The peridium is 

 simple ; that is, it does not develop in layers, and ruptures irregularly. The gleba 

 is not chambered, the basidia simply terminating lateral branches of the glebal 

 hyphae. 



(k) Sclerodermales 



In this group the nearly spherical sporophores have a thick leathery (light brown) 

 peridium, which finally becomes cracked or ruptured at apex. The leathery perid- 

 ium suggested the name of the group. The gleba is chambered, but the chambers 

 are filled with interwoven hyphae whose lateral branches bear pear-shaped basidia, 

 upon which appear four sessile spores, sterigmata not being formed. 



(1) Lycopcrdales 



These are the true puffballs, with globular sporophores which some- 

 times reach 50 cm. in diameter. The peridium is distinctly two-layered 

 and with definite dehiscence. In Lycoperdon the outer layer of the 

 peridium gradually flakes off, and the inner layer bursts at the apex. 

 In Geaster (earth star) the outer layer splits into stellate spreading seg- 

 ments, and the inner layer dehisces by a terminal pore (figs. 1123, 1124). 



The gleba contains numerous distinct chambers lined with a hymenjal 

 layer and also containing a capillitium, which is a fibrous structure of 

 interwoven branching hyphae arising from the wall of the chamber and 

 aiding in the dispersal of the spores. 



(m) Nidulariales 



These are the nest fungi, as the name suggests. The separate cham- 

 bers of the gleba become invested each by a membrane of interwoven 

 hyphae, and at maturity become freed by the breaking down of the 

 intervening tissue. When the peridium opens, forming a cuplike 

 structure, the free, membrane-covered hymenial chambers are seen 

 lying like eggs in a nest. 



(n) PhaUales 



These are the stink horns, whose sporophore is more complex than 

 that of any other fungi. The sporophore develops on the mycelium as 

 a white, egg-shaped body. The peridium is two-layered, but the tissue 

 within, which is all gleba in the other groups, is differentiated into a 

 central hollow cylindrical axis and an investing dome-shaped and cham- 

 bered gleba. At maturity the cylindrical axis elongates with great 



