128 UNIVERSITY OF COLORADO STUDIES 
lungworts. (Figs. 7 and 8 at the end of the article give typical views 
in the Canyon Forest Formation.) 
PARTIAL LisT OF PLANTS IN THE CANYON FOREST FORMATION? 
PiLants USuALLY IN SHADED SITUATIONS 
Pseudotsuga mucronata Ribes valicola 
Acer glabrum Clematis ligusticifolia 
Rhus rydber git Clematis eriophora 
Populus tremuloides Hydrophylium fendleri 
Rosa spp. Fragaria americana 
Dasiphora fruticosa Galium triflorum 
Prunus melanocarpa Vagnera stellata 
Opulaster monogynus 
PLANTS IN More Sunny SITUATIONS 
Pinus scopulorum Symphoricar pos occidentalis 
Sabina scopulorum Rhus trilobata 
Juniperus sibirica Ribes pumilum 
PLANTS ALONG THE STREAM AND IN WATER 
Salix spp. Heracleum lanatum 
Populus angustifolia Tris missouriensis 
Alnus tenuifolia Dodecatheon radicatum 
Carex and other sedges Potamogeton sp. 
Mertensia ciliata Chara sp. 
Ranunculus macounit Spirogyra sp. 
Foothill Sagebrush-Grassland Formation.—At lower altitudes this 
agrees quite closely with the Upland Dry Grass Formation noted on 
the sedimentary ridges, but with such differences as have been noted in 
the paragraph dealing with floras of granite and sedimentary areas. 
Foothill Forest Formation.*—This is the usual open xerophytic forest 
of the lower foothills in northern Colorado. Since no point above 8,000 
ft. in altitude is included in this study no truly montane conditions are 
found. The soil of the foothills is a coarse gravel of disintegrated 
granite. In some places where much washing occurs there is no soil 
at all and the bare place-rock is exposed. In other places where oppor- 
tunity exists for the collection of finer particles carried down by the 
run-off a soil of a few inches or even feet in thickness may be found. 
t This is a representative list of species selected from a large collection made by the writer and Mr. W. 
W. Robbins. 
2 Plants occurring in the foothill region but growing along the canyon-sides and creek-banks are discussed 
under ‘‘Canyon Forest Formation.’”’ This is about the same in the granite region as in the sedimentary region. 
Meadow plants of the foothill district are described with ‘‘ Meadow Formations.” 
3 In regard to limits of foothill and montane zones in northern Colorado see a note by the author in 
Science, N. S. 26:642. 1907. 
