— 68 — 



In comparison with the bryophytic flora of the ravines in the Pittsburgh 

 region^ the reviewer is forcibly struck by the lack of correspondence in the char- 

 acteristic mosses of the two regions, very few of the mosses emphasized by 

 Nichols being important, or even present at all, in the sandstone and shale ravines 

 of the Pittsburgh region. While no experts on the hepatics have worked in the 

 Pittsburgh ravines, it can probably be definitely stated that there is here no 

 such hepatic vegetation as is listed by Nichols for Connecticut, his lists of char- 

 acteristic species being about two-fifths hepatics. His description cf the boreal 

 carpet recalls very vividly to the writer the bryophytic carpet in the spruce for- 

 ests on the islands of northwestern Lake Superior and the islands and surround- 

 ing hills of the Lake Nipigon region in northwestern Ontario. 



O. E. J. 



EXCHANGE DEPARTMENT 



Offerings — To members only. Return postage should accompany the request. 



Mr.' Roy Latham, Orient, N. Y. — Biatora rubella (Ehrh.) Rabenh., and 

 Physcia obscura (Ehrh.) Nyl. var. endochrysea Nyl. 



Mr. C. C. Plitt, 3933 Lowndes Ave., Baltimore, Md. — Cetraria islandica 

 (L.) Ach., collected in Maryland. 



Mr. Severin Rapp, Sanford, Florida. — Calicium trachylinum Ach., and 

 Ricciella Sullivantii (Aust.) Evans. 



Mrs. Frank E. Lowe, 24 Brattle St., Worcester, Mass. — Grimmia leucophaea 

 Grev., from Oklahoma. 



^ Jennings, O. E. Systematic and Ecological Notes on the Mosses of Western Pennsylvania. 

 Bryologist 18: 83-93. Nov. 1915. 



