190 FLORA OF MOUNT DESERT. CLASS II. BRYOPHYTA. DIVISION I. MUSCI; MOSSSES. ORDER I. SPHAGNACEAE. PEAT MOSSES. List prepared by Edward L. Rand, assisted greatly by Edwin Faxon and Prof. Daniel C. Eaton, and arranged mainly in accordance with the writings of Dr. Carl Warnstorf, of Neuruppin, Germany. The plants catalogued in the following list have been collected 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 references to Lesqueureux 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 October, 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 prepared 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 student. 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 doubtful value of varieties of Sphagnum furnishes an additional reason for the exclusion of mere forms and sub-forms from a local catalogue of plants.