Southeastern Washington and Adjacent Idaho. 61 
unoccupied soil surface, from 30 to 40 per cent., and the appear- 
ance of several new species of a decidedly xerophytic stamp gives 
this consocies quite a different physiognomy from the well de- 
veloped prairies eastward. 
The following lists indicate the 
dominant, principal, and secondary species: 
Composition of the Agropyron Consociation 
Dominant Species 
Agro pyron spicatum 
Principal Species 
Achillea millefolium var. lanu- 
losa 
Chrysothamnus nauseosus 
Chrysothamnus nauseosus gra- 
veolens 
Chrysothamnus viscidiflorus 
Festuca pacifica 
Festuca ovina ingrata 
Lupinus ornatus 
Lupinus sericeus 
Poa ampla 
Poa sandbergit 
Tetradymia canescens 
Secondary Species 
Agoseris heterophylla 
Allium acuminatum 
Alsine nitens 
Antennaria dimorpha 
Artemisia rigida® 
Astragalus collinus 
Astragalus spaldingu 
Balsamorhiza sagittata 
Carex filifolia 
Cirsium undulatum 
Clarkia pulchella 
Cogswellia triternata 
Elymus condensatus 
Epilobium paniculatum 
Erigeron corymbosus 
Erigeron hispidissimus 
Eriophyllum lanatum 
Gilia pharnaceoides 
Koeleria cristata 
Lupinus wyethii 
Madia exigua 
Madia glomerata 
Phlox longifolia 
Plantago purshit 
Potentilla biennis 
Stipa comata 
The rabbit brush, although more common westward, is an abun- 
dant and conspicuous component of the bunch-grass community. 
3 Relict. 
