359 



The Phytecology of Peat Bogs Near Richmond, 



Indiana. 



M. S. Markle. 



Literature Used for Reference. 

 (') Transeau, E. N., On the geographical distribution and ecological relations of 

 the bog plant societies of northern North America. Bot. Gaz. 36: 401-420, 1908. 



( 2 ) Leverett, F., The glacial formations and drainage features of the Erie and 

 Ohio basins. Mon. 41, U. S. G. S. 



( 3 ) Dachnowski, M., A cedar bog in central Ohio. Ohio Naturalist, 11: No. 1, 

 1910. 



While the peat bog is a common feature of the landscape in northerly 

 latitudes, the presence of a bog as far south as Central Indiana or Ohio 

 excites considerable interest. It is the belief of modern botanists Q), that 

 these bogs originated during the period immediately following the glacial 

 period, when the area abutting on the edge of the ice approximated arctic 

 conditions, and gradually emerged from this condition after the recession of 

 the ice. Since the retreat of the ice began at its southern border, areas 

 retaining any of the primitive conditions incident to the original arctic 

 climate increase in rarity southward. In Indiana and Ohio, the Ohio river 

 formed the approximate southern boundary of the ice sheet at the time of 

 its greatest extension; so these bogs are within sixty or seventy miles of the 

 southernmost limit of glacial action and even nearer the edge of the most 

 recent ice sheet. No doubt many bogs formerly existed in central Indiana 

 and Ohio, but, with changed conditions, practically all have disappeared. 



The principal features of interest involved in an ecological study of the 

 vegetation of peat bogs are, first, the presence of a large number of xero- 

 phytic forms, a situation not to be inferred from the well-watered condition 

 of the habitat; second, the existence of many plants characteristic of arctic 

 and subarctic regions. Little study was made of the anatomy of these 

 xerophytic forms, as they are not nearly so well represented here as in the 

 northern bogs. 



The presence of boreal forms may be accounted for as follows: During 

 the glacial period, the flora of the area bordering on the ice was arctic, such 

 a flora having been able to retreat southward before the slowly-advancing 

 ice, and consisted of such forms as were able to withstand the many north- 



