— i6 — 



First of all, to those of Mrs. C. W. Harris, twelve in number, beginning in Volume 

 IV, and running through Volumes V, VI, and VII. They are illustrated, and 

 are just the kind for beginners. Then by all means read Prof. Sargent's "Lich- 

 enology for Beginners, " the tour parts of which are to be found in Volume VIII. 

 In the same volume will be found an article by Prof. Fink, "How to Collect and 

 Study Lichens." Other valuable articles are Prof. Fink's "Notes on Certain 

 Cladonias," beginning in Volume VII, and running through Volumes VII, VIII, 

 IX, and X; Mr. Merrill's "Lichen Notes," beginning in Volume VIII, and run- 

 ning through several volumes; and Prof. Riddle's "A Key to the Species and 

 Principal Varieties of Cladonia Occurring in New England" in Volume XIII. 



It is to be hoped that the interest and the enthusiasm shown in the study of 

 Lichens this year will continue unabated. 



Respectfully submitted, 

 3933 Lowndes Ave., Baltimore, Md. Charles C. Plitt, Curator 



Dec. 31, 1919. 



EXCHANGE DEPARTMENT 



Offerings — To members of the SuUivant Moss Society only. Return post- 

 age should accompany the request. 



Miss Caroline C. Haynes, Highlands, N. J. — Lepidozia sandvicensis Lindenb. 

 Alaska, U. S. Bureau of Soils Kelp Investigations Expedition, 1913. Collected 

 by Prof. T. C. Frye. 



Mr. A. T. Beals, 71 West 23rd St., New York City. — Fabronia octoblepharis 

 (Schleich.) Schwaegr. and Tortula pagorum (Milde) DeNot., collected by Miss 

 Daisy J. Levy, at Harper's Ferry, W. Va. 



Mr. Severin Rapp, Sanford, Florida. — Lecanora cupressi Tuck., collected 

 by Mr. Rapp, in Florida. 



