316 THE BASIDIOMYCETES 



opens with a pore. In Catostoiiia circinmscissiim the exoperidium 

 splits equatoriallv, the gleba adhering to the upper half, and 

 breaks away from the sterile base. Then a pore forms in the 

 endoperidium in the region that was morphologically the base 

 of the gleba. 



Species of Geaster, commonly called earthstars, never fail to 

 interest collectors of fungi. Cunningham (1927) studied the de- 

 velopment of fructifications by Geaster vehitbms. A dense layer 

 of coarse hyphae is first differentiated around the homogeneous 

 fundament. Next the fibrillose and fleshy layers of the exope- 

 ridium, the gleba, the central sterile area, and the columella are 

 differentiated. The fleshy layer gradually becomes pseudoparen- 

 chymatous. The gleba is first evident as cavities arising by split- 

 ting apart of hyphae. These cavities become compactly bor- 

 dered with hyphae that develop into basidia. Meanwhile the 

 outer ground tissue becomes an intricately woven, partly gelati- 

 nized endoperidium. Also capillitial threads grow out from the 

 columella. Finally the exoperidium splits into several lobes and 

 everts, and the spore case opens apically with a specialized mouth. 



Arachnion, typifying the Arachniaceae, has a simple, very thin 

 peridium that crumbles at maturity; capillitial threads are lack- 

 ing. The glebal chambers become peridioles, which fall apart 

 as granular particles. 



Lander (1934) studied the development of Arachnion albinn. 

 In young stages the fructifications have a peridium of two zones. 

 In the outer one the hyphae are radially arranged, whereas in the 

 inner zone they are closely and intricately interwoven. The 

 outer zone sloughs off as development proceeds; the inner one 

 becomes pseudoparenchymatous. The glebal cavities arise by 

 mechanical splitting, and gradually the basidial primordia line the 

 cavities. 



LITERATURE CITED 



Cunningham, G. H., "The development of Geaster velutmus^'' Trans. Brit. 



Mycol. Soc, 12: 12-20, 1927. 

 Lander, Caroline A., "The morphologv of the fruiting body of Lycoper- 

 don geimnatwn^'' Am. J. Botany, 20:204-215, 1933. 

 "The development of the fruiting body of Arachnio^i alburn,^'' J. Elisha 

 Mitchell Sci. Soc, 50:275-281, 1934.' 

 Lloyd, C. G., "The Geasters," Mycol. Writings, 1 (1898-1905): 1-44, 1902. 

 "The genus Bovistella," Mycol. Writings, 2 (1905-1908); Mycol. Notes, 

 25:277-287, 1905. 



