550 Part IV. Chapter 3. : | 
meadow-like as to vegetation, are occupied by /pHlobium latifolium, E. luteum, 
E. leptocarpum, Vaccinium membranaceum, Mimulus Lewisii, Cryptogramma 
acrostichoides, Echinospermum floribundum, Bryanthus, Cssidbe, Dryas Drum- 
mondii, Castilleia miniata, Arnica cordıfolia, Valeriana sitchensis and as snow 
plants, Pulsatilla occidentalis and Erythronium grandıflorum. 
Avalanche Slide Formation. A conspieuous landscape feature of the Selkirks, as 
distinguished from the. main Rockies, according to Merkel H. JacoBs, are the avalanche slides 
the bright green vegetation of which contrasts strongly with the dark green of the foreste 
The vegetation of these slides consists of dense masses of alder, Alnus sinuata (= A. viridis 
var. sinuata), willows and young birches, waieh alone survive in the usual track Br avalanche 
snow, because they bend without breaking until they come to occupy such Eee e paths 
clusively. The vegetation of these slides suggests that of Mount Katahdi ie with ae) 
age thickets of Alnus viridis; the alder thickets of Roan lerne Ne C. (see page 496); 
th e serub of the mountains of Japan, where Pinus parviflora and Alnus viridis 
abound and the subalpine bushland of Europe ?!). % 
Torrent Fan Formation. A torrent fan is a loose mass of sand gravel and boulders 
forming a level Bella. lhe RR of considerable extent at the foot of a waterfall or torrent, 
Such soil is peculiarly suited to herbaceous plants, such as, Saxifraga aizoides, Tofieldia a ER 
T. palustris, Cypripedium parviflorum, Dryas Drummondii, Dryas octopetala, Parnassia pa FE 
Antennaria lanata, Orchis le, Sisyrinchium angustifolium; Primula Maccalliana, Pe = 
vulgaris, Carex pseudoseirpoidea an er prostrata. Such an assemblage of plants is Ian 2 
near End rald Lake in the Selkirk Mounta 
Alpine Plant Formation. The summits of the Selkirk Mountains ano 
6,000 feet elevation display truly alpine conditions. They are for the most 
part bare hills covered solely with lichens, a few grasses and herbs that adopt 
the alpine habit. These summits suggest strongly the alpine peaks of Switzer- 
land and the Tyrol with the same variety of exposure and the vegetation a 4 
much the same aspect. ; 
Some of the plants of these hills, as far as known between 6,000 and 8,000 feet elevation, 
are: Vaceinium microphyllum (= V. erythrocarpum), Phleum alpinum, Delphinium bicolor, Pedieul 
racemosa, Carex nigricans, Bryanthus Arena; glanduliflorus, B. (P). empetriformis, Silene acaulis 
rming alpine mats), while the plants above 7,000 feet are Seneeio lugens, Br glauca, 
Aplopappus Brandegei. The bare Ei. & the Il-ga-chuz range farther north rise from a surface 
dotted with small ponds and lakes. The vegetation is quite en consisting of Are: Rho 
=R.rosea), Erigeron salsuginosus, Pedicularis euphrasioides, P. groenlandica var. surrecta, Menziesia 
glandulifera, Dryas octopetala, Campanula lasiocarpa and Gentiana ish, 
The following plants are true alpine species of the Selkirks: 
Botrychium simplex E. Hitcheock. Juneus Mertensianus Bong 
Phegopteris alpestris Hoppe. > arıyi Englm. 
Lyeopodium Selago L. '  Luzula (Juncoides) spicata DC. 
un. sitchense Rupr. Tofieldia borealis Wahlenb. (= T. palı 
Festuca brachyphylla Schultes. Oxyria digyna L 
risetum subspicatum 1. Silene acaulis L. 
Carex atratiformis Britton. » Lyalliüi Wats. 
pseudoseirpoidea Rydb. Alsine laeta Richards. 
»  rupestris Rydb. Arenaria capillaris Poir. var. nardifolia Lede 5 
1) WARMING. Oecology of Plants: 215—217. 
