IOWA DISCOMYCETES 53 



average not more than 2 cm. The color of the pileus also varies 

 somewhat but in all the specimens examined is decidedly darker 

 than the stem. 



FAMILY 3. KHIZINACE^]. 



Receptacle fleshy-waxy, brittle, sessile. Hymenium exposed 

 from the first, plane or convex. Asci cylindrical, operculate. 

 Paraphyses numerous, free. 



SPH^EROSOMA Klotzsch; Dietrich Fl. Boruss 467. 1841. 



Receptacle fleshy, sessile, convolute, roundish, outer surface 

 covered entirely by the hymenium, within sterile. Asci cylin- 

 drical. Sporidia spherical, verrucose, hyaline. 



Sph^rosoma echinulatum Seaver., Jour. Mye. 11 : 2-5. 1905. 



Plate 6, a — g. 



Plants gregarious or scattered, occasionally crowded, sessile, 

 1 to 8 mm. in diameter; at first almost spherical and regular 

 in outline, becoming convolute with age, especially on the upper 

 surface, often umbilicate; lower surface sterile, nearly plane, 

 attached to the soil near the center by delicate hypha?, very 

 easily detached; at first white or whitish becoming reddish- 

 brown on the exposed surface, then dark brown; the color be- 

 gins with a brown spot in the center of the upper surface and 

 spreads until it covers all of the exposed surface; at maturity 

 having a brown velvety appearance due to the large, brownish 

 paraphyses which extend far beyond the asci; under surface 

 light colored; hymenium at maturity covering the exposed sur- 

 face of the plant, composed of very large asci and paraphyses; 

 asci 40 to 50 by 300 to 500 fi, clavate, 8-spored; spores globose, 

 at first smooth, filled with numerous guttulae, and surrounded 

 with a transparent exospore, gradually becoming rough on the 

 outside, at maturity covered with spines which are several times 

 as long as broad; spines 4 to 5/x in length by 2 to 2.5^ broad at 

 the base, often bent at their apices, at maturity extending to the 

 outer surface of the exospore; spore, excluding exospore 25/* in 

 diameter, including spines or exospore, 35/x in diameter; para- 

 physes large, clavate, septate, brownish, 12 to 15/x in diameter 



