GENERA AND SPKCIES. 173 



development below the surface of the substratum. 

 The apothecia at maturity open by an apical pore which 

 renders them urn-shaped. The perithecium is black. 

 The spores are colorless, multilocular, with a thick 

 gelatinous outer spore-wall which is not rugosely 

 folded. 



Only one species came to my notice, which is south- 

 ern and grows upon various trees. 



1. Gyrostomum scyphidiferum. Thallus 'rudiment- 

 ary, uniformly spreading, greenish-gray to brownish. 

 Apothecia small, somewhat urn-shaped when mature. 

 Disk dark to black. Spores typical of the genus, 



35)u, X 13/X-. 



6. Verrucaria. 



Thallus distinctly crustose and mostly epilithic or 

 epiphloeodal. It begins its development, however, be- 

 low the surface of the substratum. In the rock-species 

 the thallus begins its development upon the surface, 

 but the lichen-acids disintegrate the rock, and the 

 greater portion of the thallus (hypha?) becomes im- 

 bedded in the loosened particles. The algie are evi- 

 dently Fleurococcus, though some authors report 

 Chroolepus as the generic alga. 



The apothecia are small, globose, more or less im- 

 mersed in the thallus and substratum, perithecium 

 dark or black. The paraphyses and spore-sacs are 

 much gelatinized ; so much so that they are scarcely 

 discernible. The spores are simple, elliptical, color- 

 less, and thin-walled. They generally bear oil-glob- 

 ules. 



The Verrucarias have a wide range, and occur upon 



