North American Fungi. 163 



NORTH AMERICAN FUNGI. 



By A. P. Morgan. 



Third Paper. 



(Continued from Vol. XII., p. 22.) 

 (Read by title Feb. 4, 1890 ) 



THE GASTROMYCETES. 

 Order II. — Lycoperdace^e. (Continued.) 

 II. Corticate. Outer peridium (cortex) at first a soft fragile 

 layer, often with external projections in the shape of warts, spines 

 or scales, adhering firmly to the inner peridium; after deliques- 

 cence drying up, and to a greater or less extent peeling off and 

 falling away; inner peridium membranaceous or subcoriaceous, 

 variously dehiscent. Columella none; in place of it the basal por- 

 tion of the gleba {subgleba) often sterile and persistent. 



Genus VII. — Tylostoma, Pers. 



Mycelium slender, fibrous, often much branched and inter- 

 woven, and with the inclosed soil forming a bulb-like mass at the 

 base of the stipe. Peridium depressed-globose, at first with a thick- 

 ened base, which at maturity elongates into a distinct stipe ; the 

 stipe lacerate-scaly, white within and fibrillose-stuffed, the apex 

 entering a deep depression in the base of the peridium, which 

 encircles it like a collar; cortex consisting of scales or warts, usu- 

 ally deciduous, sometimes persistent; inner peridium membrana- 

 ceous or subcoriaceous, dehiscent by an apical mouth. Capillitium 

 originating from the inner surface of the peridium; the threads 

 very long, hyaline, much branched and interwoven; spores small, 

 subglobose, sessile, pale brown. See Plate XVI., A. 



Plants growing on the ground oftenest in dry and sandy regions. 

 The genus is readily distinguished from all others of the 

 Lycoperdaceae by the entire peridium being mounted upon the 

 apex of the stipe. The threads of the capillitium are scarcely 

 different from the closely woven hyphae which form the inner 

 peridium ; in its internal structure the genus is related to Astraeus 

 and to Catastoma. 



§ t. Cyclostoma. Month small, circular, prominent, entire. 

 1. T. mammosum, Mich. Peridium depressed-globose, the 

 cortex of minute brown scales soon seceding ; inner peridium thin, 



