STANDLEY — FLORA OF GLACIER PARK. 351 



Pedicels spreading or ascending. 



Pods 3 to 4 cm. long; plants usually 10 to 20 cm. high .... 4. A. lemmonii. 



Pods 4 to 8 cm. long; plants usually 30 to 50 cm. high 6. A. bourgovii. 



Pods erect or strongly ascending. 

 Basal leaves glabrous or nearly so. 



Stems 30 to 60 cm. high; pods 5 to 8 cm. long 6. A. drummondii. 



Stems usually 10 to 20 cm. high; pods 4 to 5 cm. long 7. A. lyallii. 



Basal leaves covered with coarse hairs. 



Stem leaves narrowed at the base; plants 10 to 20 cm. high . . 8. A. nuttallii. 

 Stem leaves clasping; plants mostly 30 to 60 cm. high. 



Pods about 1 mm. wide, flat; leaves green, the stem leaves usually toothed. 



9. A. hirsuta. 



Pods 2 mm. wide, somewhat 4-angled; leaves somewhat glaucous, the stem 



leaves usually entire 10. A. glabra. 



1. Arabis ambigua DC. Rock slide above Many Glacier Hotel. Alaska to Wash, 

 and Mont.— Stems tufted, 15 to 30 cm. high, slender, glabrous or nearly so; stem 

 leaves spatulate or oblanceolate, entire or toothed; petals white, 6 mm. long; pods 

 erect, 2 to 3 cm. long. 



2. Arabis retrofracta Graham. Thin woods at base of Altyn Peak. B. C. to Calif., 

 Utah, and Nebr.— Stems 20 to 40 cm. high, with branched hairs; stem leaves clasping, 

 entire, glabrous; petals white or pinkish, 



3. Arabis lignipes A.Nels. Dry rocky slopes, Altyn Peak. Idaho, Mont., and 

 ,Vyo.— Stems 30 to 50 cm. high, finely hairy below; stem leaves finely hairy, clasping; 

 petals white or purplish. 



4. Arabis lemmonii S. Wats. Gray rockcress. Common above timber line, in 

 meadows or on rock slides; sometimes about snow banks at middle elevations; also 

 on exposed slopes at east entrance. B. C. to Calif, and Mont.— Stems slender, usually 

 several; stem leaves lanceolate or oblong, clasping, the basal leaves covered with fine 

 branched gray hairs; petals purple, 5 to 6 mm. long. 



6. Arabis bourgovii Rydb. Frequent on the east slope at low and middle altitudes 

 and sometimes near timber line, in meadows or low thickets or on open rocky hillsides. 

 Alaska to Man., Wyo., and Idaho.— Stems slender, often numerous; basal leaves oblan 

 ceolate, finely hairy; stem leaves lanceolate, clasping; petals pink, 6 to 8 mm. long; 

 pods 2 mm. wide. 



6. Arabis drummondii A. Gray. Frequent at nearly all altitudes, but most com- 

 mon above timber line, in woods or meadows or on rock slides or open slopes. Yukon 

 to Utah and N. Mex.— Stems several or solitary; stem leaves lanceolate, clasping, 

 glabrous, glaucous, entire; petals 6 to 10 inm. long, varying from white to purple; 

 pods 1.5 to 2 mm. wide. 



7. Arabis lyallii S. Wats. Purple rockcress. Common above timber line, in 

 meadows and on rock slides. B. C. to Calif, and Mont.— Stems usually clustered, 

 glabrous; stem leaves lanceolate, usually clasping, green, entire, glabrous; petals 

 purple, 7 to s'mm. long; pods 2 mm. wide. 



A showy and handsome plant, which remains in flower only a short time. 



8. Arabis nuttallii Robinson. Frequent at nearly all altitudes, but most common 

 above timber line, in meadows or woods or on open slopes or rock slides. Wash, to 

 Utah and Mont.— Stems clustered, slender, hairy below; petals white, 4 to 6 mm. long; 

 pods 1 to 3 cm. long. 



9. Arabis hirsuta (L.) Scop. Frequent on the east slope at low or middle altitudes, 

 in woods, thickets, or meadows or on open hillsides. Alaska to Calif., Ga., and N. B. ; 

 also in Eur. (.4. ovata Poir.)— Stems solitary or few, stout, often purplish, hairy; 



