278 



OHIO BIOLOGICAL SUKVEY 



and from year to year in the same place. It is indeed the rocky ground 

 in which the seeds of many plants fall and spring up quickly but wither 

 away for lack of a root when exposed to the scorching sun. None but 

 the cryptogams in the above list can be considered as constant inhab- 

 itants. But they are never found without the admixture of some seed 

 plants, whether of the species listed above or others. 



Most of the waifs here present are stragglers from the nearby 

 forest, but two or three are interesting in that they do not occur in the 

 forest. Ambrosia elatior found but little place in the primaeval vege- 

 tation of the region, since it is dependent on strong illumination, 

 which was denied all of the plants on the forest floor. It is interesting 

 to find it as a frequent inhabitant of such places, whether as an original 

 native or as an introduced weed. Hypericum drummundii, which 



Fig. 17. A Small Plant of Trailing: Arbutus Among the Roots of the Pines at the 



Edge of the Cliff. 



reaches its extreme eastern limits in this area, was found in a single 

 station in such a lichen formation. It was abundant in 1909, but very 

 scantily represented in 1910. 



Following the Cladonia association is a transitional shrub zone 



composed of : 



Vaccinium vacillans SmiJax rotundi folia 



Polycodium staminium Ealmia latifolia 



Gaylosaccia haccata Lespedezn repens 



Epigaea repens (fig. 17) Lechea minor 



Gaulfheria prorumhens TJypnncrnr sp. (forming tufts) 



Mitrliella repens 



