512 GLEASON AND MCFARLAND: INTRODUCED VEGETATION 
surrounding country, and the soil is of clay or of sand well mixed 
with humus. Both soil types were occupied with a dense forest of 
hardwoods, chiefly Fagus grandifolia and Acer saccharum, with 
a good mixture of Tsuga canadensis. Most of this has been 
lumbered within the past five years, and only small untouched 
areas are now remaining. Besides these two predominating types 
of vegetation, there are some rather extensive swamps with a 
dense growth of Thuja occidentalis, smaller tamarack and sphag- 
num bogs, and the usual small areas of marsh and dune vegetation 
along the shore of the lake. A full account of these has been 
published by Gates.* 
On the north shore of the lake are some small and scattered 
farms, separated by woods or slashings, and several summer 
cottages. On the south side of the lake is one small summer 
resort, with about half a dozen cottages and the biological station 
and engineering camp of the University of Michigan. Otherwise 
the shore and immediate vicinity of the lake are uninhabited. 
The known flora of the Douglas Lake region includes over 650 
species of flowering plants and ferns. These species have been 
collected not merely over the unsettled area adjacent to the lake, 
but also from the settlements, extending in some directions as far 
as six miles away from the lake. Of these 650 species, 94 are 
considered as introduced into the Manual range by Robinson and 
Fernald in the seventh edition of Gray’s Manual. Seventeen 
other species, considered to be native by these authors, are un- 
doubtedly introduced into the Douglas Lake region. These are 
Panicum capillare, Agrostis alba, Poa pratensis, Hordeum jubatum, 
Polygonum aviculare, Polygonum erectum, Amaranthus blitoides, 
Amaranthus graecizans, Euphorbia maculata, Euphorbia hirsuta, 
Verbena bracteosa, Plantago major, Silphium laciniatum, Silphium 
terebinthinaceum, Iva xanthifolia, Ambrosia psilostachya, and 
Helianthus annuus. Nine other species are probably introduced, 
although the evidence is by no means certain. These are Humulus 
Lupulus, Chenopodium hybridum, Lepidium virginicum, Lepidium 
apetalum, Lappula deflexa, Ambrosia artemisiifolia, Rudbeckia 
hirta, Achillea Millefolium, and Artemisia ludoviciana. 
* Frank C. Gates, The vegetation of the region in the vicinity of Douglas Laker 
Cheboygan County, Michigan, 1911. 14th Rep. Mich. Acad. Sci. 46-106. pl. 2-xxib. 
1913. 
