276 



OHIO BIOLOGICAL STRYEY 



Later in the suiiimiT the places of these are taken by another set 

 of j)lants, including: 



Clnut.cifiii/(t ni ■iino^d ( fijj-. 15) Circaea lutetiana 



Phyrma h ploshicliiKi Aster divaricatus 



Adicea pniniUi Ari>l()1ochUi scrjiciitdrin 



Sdiiirnlii cdrddcitsis Maliuhi rir'/iiiicd 



Fig. 15. Black Cohosh (Ciniucifuga in the Liriodendron Forest. 



Chlorophylll-less phanoganis are represented in abundance by the 

 parasitic Squaw-root, ConophijUis Americana, and Beech Drops, Lep- 

 tamium Virginiana, and the saprophytic Monotropa uni flora and Hxj- 

 popyfis Americana. 



These Liriodendron "coves" once covered a large proportion of the 

 northern section of our area. Below Clear Creek they are, and probably 

 always were, scarce. Their place is taken almost everywhere by the 

 hemlock forest which, as has been stated, does not extend north of that 

 point. 



B. The Lapland Forest 



The succession of associations in the upland forest is best seen by 

 ascending the point of one of the long, narrow ridges between the 

 ravines and walking back from the edge of the cliff thi-ough the pine 

 woods into the oak forest and around to the head of tln^ ravine where 

 the upland merges with the lowland. 



The Cliff Top. At the toi>s of the cliffs there is a narrow strip 

 of what nmy be termed a miniature lichen tundra (fig. 16), since it 

 possesses all of the essential features of the northern tundra. The sub- 

 stratum is extremely acid to litmus paper. It is exposed to the extreme 



