170 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



Riibiis saxatilis L., Antennaria dioica (L.) Gaertn., Pimpinella 

 Saxijraga L., a small species of Hicracium, Galium boreale L., 

 Campanula rotundifolia L., Asplenitim viride Huds., and A. 

 TricJwmanes L., Silene acaidis L., and last, but perhaps the most 

 attractive, the beautiful creamy white Dryas octopetala L., the 

 mountain avens. 



Other calcicolous species occurring here, many of them low- 

 land and woodland forms, or even maritime, are Oxalis AcetoseUa 

 L., Anemone nemorosa L. and Armeria vidgaris \Mlld. Of the 

 ferns, Allosorus crispus Bernh., Phegopteris polypodioides Fee, 

 P. Dryopteris (L.) Fee, Cystopteris fragilis (L.) Bernh,, and 

 Hymenophyllum Wilsoni Hooker, are most abundant. The green 

 spleenwort, a very characteristic limestone plant, has already been 

 mentioned. 



Although we have designated the region as treeless, it would be 

 hardly just to overlook an occasional specimen of Pyriis Aiiciiparia 

 (L.) Ehrh., the mountain ash. When sheltered in some rocky 

 nook, this grew to fair proportions, but in exposed locations was 

 quite stunted. The low juniper, Juniperns communis L. var. 

 montajia Ait. too, on the lofty summits where it was abundant, 

 hugged the earth so closely as to appear little more than a carpet. 

 Salix herbacea L. also might be mentioned in this connection, 

 although no one could possibly call it a tree. We found it high up 

 on the summit of one of the peaks, perhaps 3,000 feet above 

 sea level. Not a sign of other vegetation was in sight, and care- 

 ful search was necessary to locate even this plant. Its rootstocks 

 held firmly down by fiat stones, here and there, as if the hazard 

 was great, it raised itself only \ery slightly from its surroundings. 

 I collected one specimen about an inch high, bearing a staminate 

 catkin. On the particular summit in question, the winds were so 

 powerful that all the small flat stones with which the area was 

 covered had sunk into hollows made underneath them by the 

 gales. The whole summit, then, resembled a mosaic, so neatly 

 had the stones been thus fitted together. 



Three plants which never occurred in limestone soils, but 

 formed a most exclusive society of their own, were Calluna vul- 

 garis (L.) Hull, Juniperns communis L. var. montana Ait., and 

 Vaccinium MyrtiUus L. As far as I could see, no intruder ever 

 ventured into this community save Empetrum nigrum L. This 



