[Je) 
Ou 
le) 
THe PuoytTEecoLtocy or Peat Bocs NEAR RICHMOND, 
INDIANA. 
M. S. MARKLE. 
LirERATURE 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. 8. G.S. 
(8) 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 (‘), 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 
climave 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- 
phytie forms, a situation not to be inferred from the well-watered condition 
of the habitat; second, the existence of many plants characteristic of aretic 
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 giacial period, the flora of the area bordering on the ice was aretic, 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- 
