A BOTANICAL SURVEY OF THE HURON RIVER VALLEY. 
Ill. THE PLANT SOCIETIES OF THE BAYOU AT YPSILANTI, 
: IGAN. 
ForREsT B. H. Brown. 
(WITH MAP AND FIVE FIGURES) | 
INTRODUCTION. , 
THE materials for the present paper were collected from a detailed | 
survey of an area of sixty acres, known as the “bayou,” which lies } 
to the west and southwest of the Ypsilanti Highland Cemetery. It | 
includes steep slopes, a large bayou, with a stretch of floodplain and 
stream, embracing a wide variety of conditions. From a reconnais- 
sance of the entire course of the stream, it was found that many of 
the ecological conditions occurring from the source to the mouth 
“were represented at the bayou area. In this small territory, the 
plant societies have reached an unmolested development, exceptionally 
favorable for their study. 
The results here presented are the outcome of an attempt (1) to 
determine what plant societies are clearly represented, paying special 
attention to those which are found also in other parts of the stream 
course; (2) to determine so far as possible, from existing evidence, 
the influence of the factors of the environment which, both past and 
present, may account for their presence or explain their ongin- 
Naturally the stream course societies are considered, leading _ 
different line of study from the two previous papers of this series, 
in which the glacial lakes included within the valley have been made 
the subject of treatment. A careful record of all species found upon 
the area was kept anda complete herbarium made, which is to be left 
at the herbarium of the University of Michigan. The work was carried 
on under the direction of Professor V. M. SPALDING, and the ee 
desires to express his indebtedness to him for many helpful suggestions. 
DESCRIPTION. 
1. TOPOGRAPHY AND PHYSICAL GEOGRAPHY.—In the vicinity of 
Ann Arbor, Ypsilanti, and other parts of its lower course, the gre 
River flows through a wide valley with flats bordered by a 
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