190 FLORA OF MOUNT DESERT. 



CLASS II. BRYOPHYTA. 

 DIVISION I. MUSCI; MOSSES. 



ORDER I. SPHAGNACE.E. PEAT MOSSES. 



List prepared by Edward L. Hand, assisted greatly by Edwin 

 Faxon and Prof. Daniel C. Eaton, and arranged mainly in ac- 

 cordance with the writings of Dr. Carl Warnstorf, of Neuruppin, 

 Germany. 



The plants catalogued in the following list have been col- 

 lected mostly by Edwin Faxon and Edward L. Rand ; the 

 determinations are by Dr. Carl Warnstorf. In view of the 

 great difficulty of finding descriptions of the various species 

 and varieties, it has been thought wise to give freely refer- 

 ences to Lesquereux and James's " Mosses of North America," 

 and to Dr. Warnstorf's articles on North American Sphagna, 

 to be found in Coulter's Botanical Gazette, Vol. XV., in the 

 numbers for the months of June, August, September, and Oc- 

 tober, 1890, both of which works can be consulted with little 

 trouble. In cases, furthermore, where descriptions are not 

 there given, they have been either translated or specially pre- 

 pared for this list by Prof. Eaton and Mr. Faxon. It has 

 not seemed best to include forms and sub-forms herein, since 

 most of them have little value except for the critical stu- 

 dent. Very many of them are, however, represented in the 

 Mt. Desert Herbarium. On the other hand, all varieties are 

 given, without regard to the distinctions on which they are 

 founded. The value, however, of most of the so-called color 

 varieties is very doubtful, since careful observations seem to 

 prove beyond question that the color of Sphagnum varies greatly 

 with the season. It is even a matter of doubt whether a given 

 plant of any species may not quickly vary through the influence 

 of temporary external conditions, assuming at one time the form 

 of one variety, at another time the form of another. This doubt- 

 ful value of varieties of Sphagnum furnishes an additional reason 

 for the exclusion of mere forms and sub-forms from a local cata- 

 logue of plants. 



