24 Illinois State Laboratory of Natural History. 



Hob. North America (Synopsis Hepat. p. 600). (Eu.) Doubtfully 

 belonging to America. 



Bib. Syn. Hepat. p. 600, Hep. Europ. p. 167. 

 Delin. Lindenberg Monog. Ric. t XX. 



** Thallus naked on the margins, squamous underneath. 

 Scales ivhitish. 



7. R. Sorocarpa Bisch. Thallus 0.6 1.9 cm. in diam- 

 eter, pale green, or in the dry state or with age becoming albes- 

 cent, finely reticulate above, subradiately or bifurcately divided; 

 divisions oblong-linear ; acutish, deeply and acutely sulcate 

 above, much thickened beneath and furnished toward the apex 

 with a few inconspicuous white scales winch do not extend beyond 

 the margin; margins erect, when dry; spores issuing through 

 chinks which early appear along the groove above. 



Hob Thin rocky soil and cultivated fields ; Closter, N. J. (Austin), 

 Western N.Y. (Clinton), 111. (Hall), Cal. (Bolander), B.C. (Ravenel). (Eu.) 

 Bib. Syn. Hep. p. 600, Hep. Europ. p. 167. 

 Exsic. Hep. Bor.-Amer. No. 139. 



8. R. lamellosa Raddi. Thallus pale green, elegantly 

 reticulated above, subradiately divided; divisions obovate or 

 obcordate, bifid or bilobed, 0.4 1.1 cm. long, canaliculate at 

 apex; margins membranous, ascending; furnished beneath with 

 white, transverse, subundulate scales which extend considerably 

 beyond the margin; fruit as in R. Sorocarpa with which it is 

 usually associated. 



, Thin rocky soil; Closter, N.J. (Austin), Cal. (Bolander). (Eu.) 

 Bib. Syn. Hep. p. 605, Hep. Europ. p. 169. 

 Delin. Lindenberg Monog. Kic. t. XXX. 

 Exsic. Hep. Bor.-Amer. No. 140. 



ff Scales dark purple. 



9. R. nigrella D. C. Thallus dichotomously divided; 

 divisions linear, canaliculate, with entire, narrowly membran- 

 ous margins, green above, dark purple beneath and furnished 

 with transverse, semi-circular scales of the same color y which do 

 not exceed the margin. 



