A BOTANICAL SURVEY OF THE HURON RIVER VALLEY 
VIII. EDAPHIC CONDITIONS IN PEAT BOGS OF SOUTHERN 
MICHIGAN 
GEORGE PLUMER BURNS 
(WITH EIGHT FIGURES) 
In a paper read before the Society for Plant Morphology and 
Physiology at the Philadelphia meeting (1904), the author called 
attention to the fact that the plants in peat-forming lakes near 
Ann Arbor, Michigan, are by no means all xerophytic. With 
xerophytes are found many plants whose structure is either meso- 
phytic or hydrophytic, and the conclusion was drawn that in the 
vicinity under consideration one should no longer refer to a peat 
bog, as such, as a xerophytic habitat (2). 
TRANSEAU (17), in a very interesting paper dealing with the 
distribution of bog and swamp plants, stated that the two were 
found growing together in the bogs of southern Michigan, and 
accounted for the present mixture of the two kinds chiefly on 
historical and climatic grounds. 
PENNINGTON (13) concludes that the bogs in southern Michi- 
gan are heterogeneous habitats and demand detailed study. 
LivincsTon (12), DacHNowskI (7, 8), and TraNseav (18) in 
experimenting with bog water have found that it is not the same in 
all zones. The samples of water taken for experimental purposes 
were generally from under Larix, Drosera, Sarracenia, Andromeda, 
Cassandra, Vaccinium, Eriophorum, etc., that is, from zones with 
marked xerophytic plants. 
The distribution and position of zones of plants in the bogs of 
southern Michigan have been given by Davis (9), TRANSEAU 
(18), the author (3, 4), and others. On the side of greatest depth 
the following zones are found: 
I. Zone of submerged planis——Plants in this zone usually do 
not go to great depths. In many lakes no vegetation is found at 
a depth of 12 feet (3.66 m.). The chief plants aré Chara, Cera- 
105] {Botanical Gazette, vol. 52 
