BOTANICAL SURVEY— SUGAR GROVE REGION 283 



Cedar Falls. In each of these stations there are a few dozen clumps, but 

 nowhere else lias it been found, though search has been made in hun- 

 dreds of likely places. The case of Asplenium mtnifa)iuHi is extreme, 

 but the crevice plants in general are sufficiently similar to it in their 

 occurrence to make it inadvisable, except in the few instances given 

 below, to try to group them into definite associations. 



Moreover, a large proportion of the plants of the rocks really be- 

 long in neighboring associations and are merely chance seedlings of 

 plants able to endure the conditions of the cliff. This is well illus- 

 trated by the flora of a cliff at Old Man's Falls at the head of ''The 

 Gulf," which is exposed to the burning sun all day long and presents 

 very severe conditions. In this particular cliff the greater part of the 

 vegetation is made up of woody plants which alone are considered here 

 on account of the difficulty of listing the smaller herbs because of the 

 height and inaccessibility of the cliff (fig. 19). They are: 



Betula lenta Piiius virginiana 



Gaylosaccia haccafa KaJmia Jatifolia 



Tsuga canadensis Amalancier canadensis 



As already pointed out (page 270), Betula lenta has a root system 

 I'eciuiring a supply of easily available water, such as is furnished in the 

 crevices. With this requirement met it grows almost anywhere, from 

 such exposed cliffs to densely shaded bottom lands. Pinus virginiana 

 and Gaylosaccia haccafa belong in the forest on top of the cliff, but 

 are able to grow almost anywhere they can get a foothold. Kalmia 

 Jatifolia is pre-eminently a sun-loving plant with large powers of en- 

 durance of all sorts of conditions. It is accordingly frequently found 

 on exposed cliffs and in the primeval forest may have been confined 

 to such places for lack of space elsewhei'e, but it reaches its best develop- 

 ment in habitats where soil conditions as well as light exposure are 

 more favorable, as, for instance, in pastures. The hendock obviously 

 belongs in the forest below, tho its rool system resembles that of the 

 birch and its distribution is controlh-d by the same factors. This leaves 

 as a cliff plant only tlie Amahtnchier (fig. 20). which seems to show a 

 preference foi- stcc]) jihiccs i-cgardless of ollu-r conditions. 



Even of lliose plants wliicli ;ii-f li;iliil luilly Kick dwellers some give 

 clear evidt'iicc 1li;it they are so because crowded out of other habitats 

 rather than from an_\- preference for the i-oeks. I'oliipixliinii riihian. 

 for exam])le, is for the most patt as fastidious iu its clioicc of rocky 

 habitats as any phmt in oui- I'egioii. but under sjiccial circumstances it 



