Preface to the Second Edition 



is due much credit for assistance in the collection of specimens, in the prepara- 

 tion of the manuscript, and in the arrangement of the figures on the plates. — 

 O. E. Jennings, Carnegie Museum, September, 1912. 



Preface to the Second Edition 



In the thirty-eight years which have elapsed since the publication of the 

 first edition of this Manual, the mosses of the region have been much more 

 extensively collected and twenty-two species have been found which were not 

 previously known to occur in western Pennsylvania. Various friends, includ- 

 ing a number of the author's former students, especially Mr. Sidney K. East- 

 wood, have by their field-work extended our knowledge of the moss-flora of 

 our region. Very special acknowledgment is expressed to Mr. Charles M. 

 Boardman for contributing the results of his extensive field-work adding much 

 to our knowledge of the distribution of various species, and for adding several 

 species to the known flora of our region, including five species of Sphagnum. 

 To him is due in large part the revision of the treatment of the Sphagnales. 



In the preparation of this second edition of the Manual, particularly with 

 reference to nomenclature and general range of species, frequent reference has 

 been had to the second edition of Engler fii Prantl, Die Natiirlichen Pflan- 

 ::enjamilien (1924-1925); Brotherus, Die Laubmoos Fennoskandias (1923); 

 various articles in The Bryologist; and particularly the Moss Flora of North 

 America North of Mexico, A. J. Grout, Vols. I-III, (1928-1940). For 

 Sphagnum, further reference has been had to Sherrin, W. R., Ari Illustrated 

 Handbook of the British Sphagna (1927) and to Andrews, A. L., Sphag- 

 naceae, in Vol. 15, North Ajnerican Flora. 



During the years which have passed since the first edition of the Manual 

 was prepared, bryology has advanced to the point that many changes in nomen- 

 clature have become necessary in order to bring this second edition up to date. 

 As in the first edition, all drawings are original and from specimens collected 

 in western Pennsylvania. — O. E. Jennings, Carnegie Museum, June 1, 1950. 



