IOWA DISCOMYCETES 85 



then expanded or depressed, white or whitish, externally smooth 

 or downy; asci cj'lindrical, or very broad and elliptical, present 

 in small numbers, generally operculate, 16 to many-spored; 

 spores elliptical or fusiform, hyaline, smooth; paraphyses slen- 

 der, colorless. 



Three species of the genus have been studied in Iowa. 



KEY TO THE SPECIES. 



Asci 16-spored B. sexdecimsporus. 



Asci more than 16-spored. 



Asci 64-spored B. pachyascus. 



Asci many-spored, number indefinite. . . . B. crustaceus. 



*Ryparobius sexdecimsporus (Crouan) Sacc, Syll. Fung. 8: 

 541. 1889. 



Plate 34, f . i. 



AscoTjoIus sexdecimsporus Crouan, Ann, Sci. Nat. IV. 10 : 195. 

 1858. 



Ascophanus sexdecimsporus Phill., Brit. Discom. 311. 1887. 



*Ryparobius crustaceus (Fuckel) Rehm, Ber. Naturh. Ver. 

 Augsburg 26 : 17. 1881. 



Plate 33, f. ii. 



Ascoholus crustaceus Fuckel, Hedwigia 5: 4. 1866. 



Eyparobius pachyascus Zukal ; Rehm, Hedwigia 27 : 167. 



1888. 



Plate 34, f. ii. 



Gregarious or scattered, very minute, scarcely visible with the 

 lens, 70 to 90/x, in diameter, partly immersed, yellowish-brown; 

 asci few in each plant, 3 to 5, broad, acute at the base, not stipi- 

 tate, 70 to 76 by 32 to 35/a, many-spored; spores minute, ellip- 

 tical, 5 to 7 by 3ju,; paraphyses not distinct. 



Grown on cow-dung in the laboratory, Iowa City. 



Plants very small and could not be distinguished except as 

 they were collected with other species. The number of asci in 

 each plant is small varying from three to five. The entire ascus 

 is filled with the spores which seem to be arranged radially 

 around the outside of the ascus. The exact number of spores in 



