VEGETATION OF ROCK HOUSES. 75 



The following are frequent in the openings of woods and on their 

 borders: 



Vagnera racemosa. Tiarella cordifolia. 



Umlaria puberula. Hypericum virgatum. 



Uvularia sessilifolia. Scutellariaincana. 



Iris cristata. Phlox divaricata. * 



Syndesmon thalictroufrx. Mertensia virginica. 



Anemone quinquefolia. Vinceloxicum hirsutum. 



A nem one virginica . Gentiana villosa . ' 



Ranunculus recurvatns. Galium circaezans. 



Cimidfuga racemosa. Houstonia caerulea. 



Trautvetteria carolinensis. Deringa canadensis. 



Viola hastata. Podophyllum pellatum . l 



Viola multicaulis. Sanguinaria canadensis. 

 Viola pubescens. 



On the higher shady banks of water courses are found: 



Porteranthus (Gillenia] stipulaceus. Stocky s cordata. 



Porteranlhus trifoliatus. Zanthorhiza apiifolia. 1 



In the more or less dense forest, covering hill and dale, are to be 

 found: 



Orchis spedabilis. Aralia racemosa. 



Cypripedium parviflorum. 1 Sanicula marilandica (rare). 



Arisaema guinatum. Phryma leptostachya. 



Circaea lutetiana. Frasera carolinensis. 1 



Hydrastis canadensis 1 (scarce). Cynoglossum virginicum. 



Bicuculla cucullaria. Obolaria. virginica. 



Dentaria diphylla. Solidago flexicaulis. 



Cubelium concolor. /Solidago vaseyi. 

 Panax quinquefolium. 1 



The Solidago vaseyi has been collected near Holmes Gap (1,500 

 feet), and is known from a few localities on the highest ranges of the 

 Carolinas and Georgia. 



On the restricted flat semiswampy places, not infrequently met with 

 on the Warrior table-land, open or slightly under cover, the following 

 are most frequently seen: 



Cyperus pseudo-regetus. 1 Phlox maculata. 



Carex lupulina. 1 Lysimachia quadrifolia. 



Car ex lurida. 1 Genliana elliottii. 1 



Habenaria ciliaris. 1 Bidens involucrata. 



Xyris flexuosa. 1 Coreopsis grandiflora. 



Rhexia virginica. 1 Doellingeria infirma. 

 Ludwigia alternifolia. 1 



Mesophile plant associations of rock houses. On the perpendicular 

 walls at the head of the deep narrow gorges are found shelves of hard, 

 resisting sandstone with the softer strata beneath them worn away by 

 the action of the percolating surface water. The wide and deep exca 



1 Occurs also in the Louisianian area. 



