﻿200 BOTANICAL GAZETTE [march 



trees and the north exposure of the bluff face, the sun can shine 

 upon the talus not more than an hour or two each day. Fur- 

 ther, partial shade is afforded by a line of shrubs, six to ten feet 

 high, growing along the bluff face at the top of the talus 

 ^. /). The face of the bluff above the talus is covered 

 with species of Stereocaulon, Cetraria, Ramalina, Buellia, 

 Usnea, Lecanora, Alectoria, Evernia, and Pannaria, while the 

 talus below is covered with a perfect maze of Cladonias and 

 mosses, with species of Stereocaulon, Peltigera, Sticta, arid 

 Parmelia interspersed here and there. The Cladonias have 

 doubtless wandered to the talus from the level woods to the 

 north below and yet more from the south on top of the bluff, 

 and are especially numerous as to individuals and species 

 because such an ombrophytic habitat is well adapted to the 

 development of lichens having erect podetia surrounded by a 

 protective pseudo-cortex of densely interwoven hyphae. These 

 podetia are of course through the cortical hyphae protected 

 against too rapid evaporation of moisture, and thus the Cla- 

 donias are able to rise from the substratum in a more or less 

 erect position and successfully compete with the mosses for 

 possession of the talus blocks. 



The species and varieties easily detected in an area of the 



talus one rod square are 



gracilis 



1 



furcata para 



ioxa, C, fimhriata, C, fimbriata apolepta, C. jimbriata 



firnbriata 



deformis, C. pyxidata, C. 



Sif^ 



ifera, C, squamosa, C. caespiticia 



{fig^ 



Ipestris. Of these the first and its 



half-dozen are common enough. From the tree line to the base 

 the talus is literally covered with Cladonias, of which the one 

 for which the formation is named predominates even more 

 largely than on the portion of the talus above the tree line. 

 On this lower shaded portion of the talus, the Cladonias grow 

 most abundantly on the old logs that cover the greater portion 

 of the base of the talus. Unfortunately, it was found necessary 

 to remove a few of the trees, shrubs, and logs growing upon 



^' J^=- *- 



