PIPER FLORA OF THE STATE OF WASHINGTON. 49 



and the "black sunflower" (Wyetkia amplexicaulis) often occupy 

 large areas in nearly pure growths. 



Along the streams and by springs willows of several species, to- 

 gether with a thorn {Crataegus hrevispina) form thick copses. Occa- 

 sionally aspens {Populus h^emidoides) and cottonwood (P. tricho- 

 carpa) form groves. The commoner undershrubs are snowberry 

 {Symphoricarpos racemosus) , roses {Rosa nutkana 'dnd R.pisocarpa), 

 and gooseberries {Rihes inerme and R. irriguum,). Intermingled 

 with these are other shrubs of less importance. Occasionally, how- 

 ever, the birch {Betula microphylla) is the most abundant shrub. 

 The accompanying herbaceous vegetation is richer and more varied 

 than on the hills, but the individuals are relatively less abundant. 

 Among the more conspicuous are : 



Castilleja miniata. Solidago scrotina. 



Clematis hirsutissima. Vrtica lyallii. 



Heracleum lanatmn. Vrtica holosericea. 



Lupinus leucophyllus. Valeriatia ceratopliylla. 



Sidalcea oregana. ' Veratruni californicum. 



The north hillsides flora consists mainly of plants found in the 

 " draws," though there are several species >vhich, while not entirely 

 confined to the north hillsides, flourish there especially well. Such 

 are the adder's tongue {Erythronium grandiflorum) ,h\neherry {Vac- 

 cmium cespitosum) , Trillium petiolatum, and Capnorea villosula. 



The scablands, which as before stated lie mainly between the zone 

 of sagebrush and that of bunchgrass, possess in large part the flora 

 of the latter. A few species, however, are quite characteristic of 

 these basaltic outcroppings. One of these is a service-berry {Amelan- 

 chier cusickii) which often occurs in the cracks of basalt crags. The 

 rock-rose or bitterroot {Lewisia rediviva) occurs abundantly in the 

 crevices of " scab," making a brave show with its beautiful rose- 

 colored flowers. Where a thin soil is formed, the scabland sagebrush 

 {Artemisia rigida) often occurs in considerable areas. Other plants 

 usually found only in scablands are : 



Arabis cusickii. Lomatium grayi. 



Eriogonum thymoides. Lomatium macrocarpum. 



Lomatium canbyi. Talinum spinescens. 



Lomatium farinosum. Viola trinervata. 



The conspicuous basaltic outcroppings along canyons and coulees 

 are locally known as " rimrock." The rimrock flora is in general the 

 same as that of scablands of similar elevation. (PI. XIII.) 

 29418—06 M 4 



