Jennings: Manual of Mosses 



author has. naturally, had recourse to the various works of Sullivant, Les- 

 quereux & James, Barnes SC Heald, Grout, and others among the American 

 bryologistb, and, among the European bryologists, particularly Dixon and 

 Jameson. In the determination of the Sphagnums the works of Warnstorf, 

 Roth, and Braithwa te were found particularly useful, while in the treatment of 

 synonymy the main reliance has been placed en the Index Bryologicus of 

 E. G. Paris. 



In nomenclature the rulings of the International Botanical Congress, held 

 in Brussels in 1910, have been followed, taking as the starting point the Species 

 Muscorum of Hedwig (1801) and the three subsequent "Supplements" by 

 Schwaegrichen, Hedwig's having been the first comprehensive work to deal 

 with the messes in a modern way. In the present Manual the principle of 

 priority has been followed without exception, dating from Hedv»'i[T, and a few 

 new combinations have been found necessary. Plant names which have been 

 adopted from pre-Hedwigian sources without important changes in nature or 

 in status are indicated by a double citation of authors, the pre-Hedwigian 

 author being cited first, followed by a comma, and then the name of Hedwig 

 or Schwaegrichen or of the post-Hedv.'igian author, as the case may be. In 

 case the name of the plant has been derived from pre-Hedwigian sources, but 

 has been used in a different rank or, in the case of species, has been trans- 

 ferred from one genus to another, the name of the pre-Hedwigian author has 

 been enclosed in brackets. 



So far as it has been possible to do so, the descriptions of the various 

 species are based entirely on specimens collected in the region covered by the 

 Manual. Where specimens of species reported as occurring in the region or 

 thought likely to be eventually discovered in the region, have not been avail- 

 able for description, the description has been in part compiled and in part 

 drawn up from specimens from other regions. It has been the aim to repre- 

 sent by original drawings, completely and in considerable detail every species 

 of which specimens collected in the region of the Manual have been available. 

 In the list of specimens, which, in the Manual, follows the description of each 

 species, the particular specimien figured has been so indicated and the fact that 

 the specimen is in the Herbarium of the Carnegie Museum. All drawings are 

 the work of the author alone, and, with the exception of a few of the larger 

 habit sketches, all drawings have been first traced by means of the camera 

 lucida, thus insuring a reasonable degree of accuracy in the relative position, 

 shape, and size of the various structures figured. The drawings of most of 

 the dissections have been made from permanent glycerine-jelly mica-covered 

 slides which are to be found in the Herbarium in the proper pocket with 

 the specimen. 



Special acknowledgment should be here made to Dr. W. J. Holland, 

 Director of the Carnegie Museum, without whose generous and kindly support 

 the collections could not have been made and properly studied nor the Manual 

 prepared. To Professor J. C. Fettermann, of the University of Pittsburgh, is 

 due many thanks for suggestions and criticism, and to Mrs. O. E. Jennings 



