With the grasses and sedges, possibly earlier, appear Lycopo- 

 dium Selago, L. annotinum pungens, Arenaria grcenlandica, and 

 Potentilla tridentata. -Edaphic conditions seem to largely deter- 

 mine the nature of the pioneer forms. Prenanthes trifoliolata, 

 P. Bootii, Solidago macrophylla, and Scirpus caspitosus are 

 associated forms less common but not rare. 



The heaths follow next. Hmpetrum nigrum, Vaccinium 

 Vitis-Idcea, V. pennsylvanicum an gusti folium, V. uliginosum, 

 Diapensia lapponica are among the pioneers. Ledum latifolium, 

 Kalmia an gusti folia, Kalmia glauca, Arctostaphylos alpina, and 

 Rhododendron lapponicum are of less frequency but are asso- 

 ciated forms. Of more local occurrence are Bryanthus taxi- 

 folius, Loiseleuria procumbens, and Cassiope hypnoides being 

 largely restricted to the lower slopes. 



The Alpine Tundra mat (Figs. 2, 3) is widely distributed, 

 covering more than one-half the upper part of the mountain. 

 (Fig. 2). On the crest, summits, and table-land it reaches per- 

 haps its highest and most characteristic development, yet , it 

 extends down upon the "saddle," spurs and higher slopes, and is 

 in a very characteristic state upon the floor of the North basin, 

 for reasons which have been sufficiently set forth above in our 

 discussion of the origin of the flora. Its composition is not uni- 

 form, varying much in its species with edaphic conditions. In 

 one place Vaccinium Vitis-ldcea is dominant, Diapensia lap- 

 ponica characterizes the alpine mat in another, Arctostaphylos in 

 another, Ledum latifolium in still another, while still again the 

 mat may be almost wholly peopled by Juncus trifidus and the 

 heaths conspicuously absent. 



Along the brow of the "tableland," "saddle," and vari- 

 ous spurs a very different condition exists and consequently 

 the plant succession is modified. Here disintegration is rapid 

 and drainage excessive. For several feet, in places yards, back 

 from the brow a gravelly granitic soil of four or five inches in 

 depth is destitute of vegetation. The crustaceous lichen stage 

 is absent, as are also the fruticose forms which are excluded on 

 account of their inability to take root and hold their position. 

 The conditions then for plant life are very severe and only 

 particularly adapted forms are enabled to withstand these 



32 



