374 BOTANICAL GAZETTE [NOVEMBER 
given. By way of illustration, however, a list of the plants observed in a 
particular mixed grassland station may be presented, and this is followed by a 
list of some other species commonly found in the community, but which happen 
to have been absent from the station selected. The station is on the east slope, 
not far from the top, of a hill a little over two miles west of the mountain-front 
and a little north of Boulder, in section 36,T 2N,R72W. The hill is marked 
in the Boulder quadrangle of the United States topographic atlas by the altitude 
of its summit, 7168 ft. The spot studied most in detail is at about 7000 ft.; 
exposure is considerable, as the slope is even and treeless; drainage is probably 
quite rapid; the soil coarse, with but little humus; proportion of bare surface 
about 15 per cent on June 18, when the list was made. All of the plants 
marked as abundant or frequent occur in practically every square meter of 
surface. 
PLANT COMPOSITION OF A TYPICAL MIXED GRASSLAND STATION 
Bouteloua oligostachya (a) Eriogonum umbellatum (2) 
Phacelia heterophylla (a) 
Chrysopsis villosa (?) (a) 
Senecio oblanceolatus (a) 
Geranium Parryi (a) 
Artemisia frigida (a) 
Aragallus Lambertii (a) 
) 
Ceras se 
Aragallus albiflorus (//) 
Stipa comata (/f) 
Opuntia fumes (2) 
Oreocarya virgata (7) 
Artemisia eetiai is var. (i) 
Astragalus flexuosus (7) 
Eriocoma cuspidata (7) 
Mamillaria vivipara (2) 
Sitanion brevifolium (7) 
Gaillardia aristata (7) 
Phlox multiflora (2) 
Potentilla pennsylvanica strigosa (7) 
Euphorbia robusta (2) 
Townsendia grandiflora (7) 
Allium sp. (2) 
The order in which the species are listed gives a rough approximation of 
their relative importance as making up a part of the vegetation, in descending 
e. The names of plant species elsewhere frequent in the association follow: 
ADDITIONAL SPECIES FREQUENT IN MIXED GRASSLAND 
Woodsia oregana 
Selaginella, two spp. 
Aristida longiseta 
Echinocereus viridiflorus 
Lithospermum multiflorum 
