Southeastern Washington and Adjacent Idaho. 59 
valleys southward and westward. Here its size and abundance 
make it an important floral component. Lupinus leucophyllus 
is the most mesophytic of the group and is found at home typ- 
ically on moist north slopes or in the valleys. 
In the lower ground considerable areas are given tone by the 
white flowers of Galium. But with the increasing stress of 
drought the aestival aspect passes, lingering only in moister situa- 
tions. Then the leaden landscape of dry balsam-root, drying 
grasses, and silvery-leaved lupines and hawkweed is relieved only 
by the yellow and the blue of sparsely spaced goldenrods, asters, 
and Hoorebekia. 
I have described very briefly the well developed prairie repre- 
sented by the Festuca consociation. Westward and southward 
as the altitude decreases and the rainfall is correspondingly less, 
many important species either become fewer in individuals, or 
are found only in the most mesophytic situations, or indeed dis- 
appear entirely. Among these the following may be enumerated: 
Astragalus arrectus Leptotaenia multifida 
Carex geyert Lithospermum ruderale 
Cirsium foliosum Potentilla blaschkeana 
Drymocallis convallaria Rosa nutkana 
Gaillardia aristata Rosa pisocarpa 
Galium boreale Sidalcea oregana 
Geranium viscosissimum Steversia ciliata 
Helianthella douglasi Symphoricarpos racemosus 
Heuchera glabella Trillium petiolatum 
Hieracium scouleri Viola adunca 
Hoorebekia racemosa Wyethia amplexicaulis 
The Agropyron Consociation 
This community in an early stage of development covers hun- 
dreds of acres of the thin soil in the scab-lands. The characteris- 
tic plant is Agropyron spicatum. Areas characterized by this 
consociation are peculiar because of the growth form of the domi- 
nant species as well as a number of the commoner interstitials 
which show various degrees of the same bunch habit. Numerous 
59 
