—44— 
is this steep-flanked ravine, its floor from sixty to seventy feet lower than the 
surrounding upland and in which occur the "Big Springs", sources of Carp 
Creek. The Gorge is situated about a mile from the Biological Station. 
The Streams. — There are a number of these, varying in size, in flow and 
swiftness, in temperature, and in character of banks, but all agree in having a 
sandy, gravelly or muddy floor, rocky stream beds being conspicuously lacking 
in this region. 
Coniferous Forest Sivamps. — Low wet grounds commonly are wooded main- 
ly with white cedar and black spruce. A typical swamp of this kind is Reese 's 
Bog, about a mile from the Station, which occupies a strip perhaps two miles 
long and up to half a mile wide along the northern shore of Burt Lake. The 
tamarack predominates locally in wooded swamps, more especially in areas 
that have been burned over. 
Open Marshy Swamps. — These are characterized typically by the abundance 
of sedges and grasses and the scarcity of sphagnums. Commonly they are peri- 
odic swamps and the underlying mineral soil is but sparingly covered with organic 
debris. 
Open Sphagnum Bogs. — These are of the familiar sort, characterized by the 
abundance of sphagnum mosses and ericaceous shrubs and by the presence of 
a deep peaty substratum. 
In the detailed list which follows, generally speaking, the habitat relations 
of each species are indicated, together with its comparative frequency in the region 
under consideration. For the majority of species definite stations are cited, 
these stations being represented by specimens in the Herbarium of Yale Univer- 
sity and most of them also by duplicate specimens in the Herbaria of the New 
York Botanical Garden and of the University of Michigan. For species recorded 
as "common", however, as well as for some of those recorded as "frequent", 
specific stations are not given: in all such cases a definite "Douglas Lake" 
station can be assumed. Except where otherwise noted, all records are based on 
the writer's collections. Of the localitie^^mentioned, aside from those that can be 
found on any good map of this region or for which the name given is self-explan- 
atory, Fontinalis Run, Reese's Bog, and Colonial Point adjoin Burt Lake; North 
and South Fishtail, Grapevine Point, Polypody Bluff, Bryant's, Fairy Island, 
and Pine Point border on Douglas Lake; while Lancaster, Munro, Vincent and 
Mud Lakes, together with the various "bogs", are all in this immediate vicinity. 
For assistance in the determination of material grateful acknowledgment 
is made to Mrs. E. G. Britton, Dr. A. L. Andrews, Mons. G. Dismier, Dr. A. W. 
Evans, Dr. A. J. Grout, and Mr. R. S. Williams. 
Marchantiaceae 
CoNOCEPHALUM CONICUM (L.) Dumort. Common along overhanging banks 
of streams in moist woods. 
Marchantia polymorpha L. Common on wet ground in the open, but 
especially in swamps liiaL ha\'c recently been burned over. 
