12 
The: Colorado Expe:rime;nt Station 
rado candy-tuft ( Thlaspi coloradense), double bladder-pod (Phy- 
saria didymocarpa) , Indian millet (Eriocoma cuspidate), sand¬ 
wort (Arenaria fendleri), oat-grass (T rise turn montcmum ), stipa- 
grass ( Stipa viridula), fescue-grass ( Festuca arizonica) , stick- 
seed ( Lappida occidentalis), phacelia ( Phacelia leucophylla) , ger¬ 
anium (Geranium fremontii) , beard-tongue (Pentstemon humilis), 
vetch (Astragalus shortianus), and common sage (Artemisia fri- 
gida). 'The cooler and moister north exposures are frequently 
clothed with Douglas fir (Pseudotsuga mucronata), aspen (Popu- 
lus tremuloides), Rocky Mountain maple (Acer glabrum), spring 
anemone or pasque flower (Pulsatilla hirsutissima) , saxifrage 
(Saxifraga rhomb oidea), buckbean (Therm op sis divaricarpa ), 
bedstraw (Galium bore ale), and false Solomon’s seal (Vagnera 
s tell at a). 
Pig. 4.—In the Wet Mountain Valley. The view is looking due west. 
Note the bare south exposures and timbered north exposures. 
Fig. 4 is a scene in the Wet Mountain Valley, and it shows 
very clearly the effect of exposure upon local conditions that in¬ 
fluence plant growth. The view is looking due west. Douglas fir 
and white fir clothe the north-facing slope, while grasses and low 
shrubs dominate the south-facing slope; the two plant commun¬ 
ities meet sharply at the crest of the slope. In many of the east- 
west valleys of the Western Slope, pinyon pine and juniper 
abound on the warm, dry, south exposures, while Douglas fir and 
