CONTENTS 



Introduction 1 



Directions for collecting, preparing and preserving specimens of mosses .. 7 



Abbreviation of signs used in the manual 10 



Analytical key to the genera of mosses of western Pennsylvania 10 



Systematic Treatment 



Order I. Sphagnales - 20 



Order II. Andreaeales - 42 



Order III. Bryales - 44 



Acrocarpi. Fc-.milies 1-23 44-172 



Pleurocarpi. Families 24-34 172-307 



Glossary of bryological terms used in the manual 308 



Explanation of the method of lettering the figures ., 324 



Plates I-LXXII 325-326 



Index 313 



6627 



