444 : RYDBERG: PHY 
Stipa Portertt 
Stipa Richardsonu 
Calamagrostis Scribnert 
Poa tricholepist 
Anticlea coloradensist 
Disporum trachycarpum 
Trautvetteria mediat 
Atragene tenutloba 
Actaea viridiflorat 
Ozomelis stenopetalat 
Ozomelis Parryit 
Drymocallis fissa 
Thermopsis pinetorumy 
Thermopsis diversicar pat 
Atelophragma aboriginum 
APHICAL NOTES 
c. Endemic 
Atelophragma Macouniu 
Aragallus Richardsonu 
Hedysarum boreale 
Viola scopulorum 
Osmorrhiza intermedia 
Primula Parryt 
Androsace pinetorumt 
Pentstemon secundiflorust 
Pentstemon virenst 
Erigeron superbust 
Anaphalis subalpina 
Arnica pumila 
Arnica sylvaticat 
Notholaena Fendleri{ 
Selaginella Underwooditt 
II. SPRUCE FOREST 
This is mostly confined to the north slopes of the mountains, 
which are much cooler and moister than the south slopes. As in 
the Subalpine Zone, the principal tree is the Englemann spruce, 
Picea Engelmannii. In some places this forms pure stands but 
usually it is mixed with the balsam fir, Abies concolor, the Colorado 
blue spruce, Picea Parryana, and the Douglas fir, Pseudotsuga 
mucronata; and, in the northern part, sometimes with the lodge- 
pole pine, Pinus Murrayana. The undergrowth is much the same 
as in the Pine Forest, and no attempt has been made to distinguish 
the undergrowth of the Pine Forest from that of the Spruce Forest. 
Ill. ASPEN GROVES 
These are found on richer more gentle slopes, both on the 
south and the north side of the mountains, but on the former only 
where there is a certain amount of moisture. The principal tree 
is the quaking aspen, Populus tremuloides, which I count as a 
transcontinental tree, as the western form, P. aurea Tidestrom, 
is so closely related to the eastern. The trees of the southern 
Rockies belong evidently to the latter, but in the Northern Rockies 
it is unknown where the range of one ends and that of the other 
begins. The vegetation consists mainly of the following plants: 
