Jan., 1915.] Plant Distribution in Ohio. 411 



According to Merriam, the northeastern part of Ohio belongs 

 to the Transition Zone and all the rest of the state to the Upper 

 Austral Zone. 



In map I are indicated some of the more important physio- 

 graphic lines in Ohio as follows: 



a-a, Western boundary of the Alleghany Plateau, following 

 closely the eastern limit of the Ohio Shale. 



b-b, The terminal moraine or glacial boundary. 



c-c, Lake Erie Ohio River divide. 



d-d, North-west beach of glacial Lake Erie; the country 

 beyond this is deeply covered with drift underlain with 

 shale. 



e, Edge of the higher hill country. 



According to all the data available and the lists of plants 

 given below, Ohio apparently falls into four general regions or 

 areas and for a preliminary survey seven natural plant regions 

 may be recognized. These areas will at present not receive 

 final, distinctive phytogeographic names but be indicated simply 

 by their physiographic character or their geographic position as 

 follows: (See Map II.) 



I. Glaciated Alleghany Plateau, belonging to the "Tran- 

 sition Zone." 



II. Non-glaciated Alleghany Plateau, eastern division, 

 including most of the Muskingum river basin, and the 

 counties to the east. 



III. Non-glaciated Alleghany Plateau, western division, 

 containing the highland between the Muskingum and 

 Scioto. 



IV. The Miami Area, mainly a glaciated calareous region. 



V. The Great Black Swamp Area and contiguous country. 



VI. The Williams County Area. 



VII. Sandusky Bay and Lake Erie Islands Area. 



The seven areas may be briefly delimited and characterized 

 as follows: — 



I. The Glaciated Alleghany Plateau has its southern bound- 

 ary in the terminal moraine and its western boundary at or a little 

 beyond the limits of the Appalachian highland which approaches 

 the eastern line of the Ohio Shale. As stated this area is recog- 

 nized as a part of the Transition Zone of Merriam. Interesting 

 plants found in this part of the state are : 



Pinus strobus 

 Calla palustris 

 Xyris flexuosa 

 Lysias orbiculata 

 Pyrola secunda 

 Andromeda jjolifolia 



