160 BOTANICAL STATIONS. 



equally in the yailahs and among the higher 

 mountains, and in the low country near the sea. 

 In the latter we found the serpentine in spring 

 always indicated by the presence of Senecio squa- 

 lidus, a conspicuous little Erophila, and the fern 

 Cheilanthes odora, which occupied the place taken 

 by the Acrostichum lanuginosum on the limestone. 

 Peculiar species of Alyssum also distinguished the 

 herbage of the two rocks. 



In order to establish a comparison between 

 the vegetation of the serpentine and the lime- 

 stone in the mountain region, two points were 

 selected, the one an isolated hill of serpentine, 

 near Balbura, rising about six hundred feet out 

 of a plain, four thousand seven hundred feet 

 above the sea ; and the other, that portion 

 of the peak of Cragus corresponding in eleva- 

 tion. Every plant in flower was gathered on each 

 station and such trees as were present noted. 

 Both localities were equally bare and rocky, and 

 the herbaceous vegetation on each consisted of 

 little patches of plants growing in crevices of the 

 rocks, and was remarkable for presenting scarcely 

 any grasses among the species composing it. 



On the serpentine at the Balbura station 

 we gathered forty-eight species. They belonged 

 to the following genera : 



