248 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



The herbaceous plants are rather numerous, as shown in the follow- 

 ing list. The species marked with an asterisk grow only on rock 

 slides and in the most exposed places. 



Phleum alpinum. 

 Tojieldia palustris. 

 Eriogonum depressum. 

 Eriogonum androsaceum* 

 Rumex acetosa. 

 Oxyria digyna. 

 Polygonum viviparuvi. 

 Claytonia megarrhiza.* 

 Claytonia lanceolata. 

 Silene acaulis. 

 Lychnis apetala.* 

 Cerastium alpinum.* 

 Stellaria americana.* 

 Stellaria laeta. 

 Sagina saginoides. 

 Arenaria nuttallii* 

 Arenaria formosa. 

 Arenaria rossii* 

 Trollius albifloru^. 

 Aquilegia jonesit* 

 Anemone parvijlora. 

 Papavcr pygmaeum* 

 Draba glacialis. 

 Draba andina* 

 Draba oligosperma.* 

 Draba crassifolia. 

 Smelowskia americana. 

 Arabis lyallii. 

 Parnassia kotzebv£i.* 

 Sedum integrifolium. 



Saxifraga rhomboidea. 

 Saxifraga oppositifolia.* 

 Saxifraga adscendens. 

 Saxifraga rivularis. 

 Saxifraga lyallii. 

 Leptarrhena pyrolifolia. 

 Potentilla nivea.* 

 Potentilla glaucophylla. 

 Lupinus minimus. 

 Astragalus bourgovii. 

 Oxytropis alpicola. 

 Oxytropis parryi.* 

 Epilobium alpinum. 

 Epilobium anagallidifolium. 

 Polemonium viscosum.* 

 Phacelia lyallii. 

 Myosotis alpestris. 

 Pentstemon ellipticus. 

 Veronica wormskjoldii. 

 Castilleja ocddentalis. 

 Pedicularis contorta. 

 Crepis nana.* 

 Solidago ciliosa. 

 Erigeron lanatvs.* 

 Erigeron unalaschkensis. 

 Erigeron jucundus. 

 Arnica alpina. 

 Arnica tomentosa.* 

 Senecio conterminus.* 

 Senecio fremontii. 



Not all the species listed are confined to this zone, but most of 

 them are so limited. Few of them are found below the Hudsonian 

 Zone, except under abnormal conditions. 



Most of the plants of the Arctic-Alpine Zone may be found in any 

 locality above timber line. The majority are widely dispersed in 

 this belt, but some are of local occurrence. On rock slides (see 

 pi. 44, B) the mdividuals are not numerous, and they are often half 

 hidden under the rocks; consequently one occasionally stmnbles 

 upon a single individual of a given species, but searches m vain for a 

 second one. It is hard to see how plants can grow on the rock 

 slides, where there is no soil visible and where the rocks are rolling 

 downward almost constantly. Most of the plants fomid in such 

 places have remarkably long roots, and in many instances the roots 

 are very elastic, so that a plant is not easily torn up or broken off 

 if a rock rolls over it. 



