CATALOG OF PLANTS. 65 



CATALOG OF PLANTS. 



BY C. K. DODGE. 

 INTRODUCTION AND GENERAL DESCRIPTION OF THE REGION. 



So far as known to the writer, no botanist has ever given special 

 attention to the flora of the region here considered, except Prof. C. A 

 Davis, who more than 10 years ago, while engaged in geological work, 

 noted and reported 300 species. ^ 



The observations on which this paper is based were mostly made by 

 the writer while attached to the field party of the Michigan Geological 

 and Biological Survey, during the summer of 1908, and on supple- 

 mentary trips to this region in June, July, August and September, 

 1909. In the course of the work, Stony Island, North Island, Charity 

 Island, and Little Charity Island were visited, and the whole shore 

 between Sebewaing and White Rock traversed. Special attention 

 was paid to the shore and sand dune plants, but at the same time 

 notice was taken of nearby fields and the adventive plants and weeds 

 in villages, gardens, about country dwellings and near fishery buildings. 



Huron County lies at the north end of a peninsula often called "the 

 thumb " and is bounded on the east by Lake Huron and on the west by 

 Saginaw Bay. (See map.) The proximity of so much water affects 

 its climate, making it average about three degrees warmer in winter 

 and three degrees cooler in summer than in the middle of the state, 

 but the principal effect of the lakes is to check oscillations and extreme 

 variations in temperature. - 



Beginning near Point aux Barques, sand ridges or sand dunes extend 

 almost continuously to Bayport, Sebewaing and southwest into Tuscola 

 County, but not always close to the shore. ' From Sebewaing to Sand 

 Point much of the shore is of the mud flat type, the dunes being some 

 distance back. These dunes owe their origin exclusively to local 

 conditions and the combined action of waves and wind, the former 

 bringing the material to the shore, the latter heaping it uj) above the 

 water level. They are formed of fine pure sand blown up mostly into 

 long and often somewhat sinuous ridges, occasionally into heaps, ranging 



^Geological Survey of Michigan. Vol. VII, p. 234. 

 2Loc. cit . p. .31 et seq. 



^For a report on the geology of Huron County, .'te Vol. VII. pt. II, Geological Survey of 

 Michigan, by Alfred C. Lane. 



