170 CRUCIFERAE. 



flowers white or purple; pod long-linear, compressed parallel 

 to the partition; valves more or less 1 -nerved; seeds flattened, 

 usually winged, in one or two rows. 



Seeds wingless; flowers white. 



Basal leaves pinnately cleft into short and broad seg- 

 ments. A. lyrata. 

 Basal leaves entire; cauline auriculate. A. glabra. 

 Seeds winged or wing-margined. 

 Seeds arranged in a single row. 



Cauline leaves cordate or auriculate at base. A . Mrsuta. 



Cauline leaves not cordate nor auricled. 



Pubescence of very fine stellate hairs or none; pods 



broad. A. platysperma. 



Pubescence of simple or forked hairs; pods narrow. 



Petals small, not exceeding the sepals. A. olympica. 



Petals much longer than the sepals. A. furcata. 



Seeds more or less distinctly in two rows. 



Pods reflexed. A. patula. 



Pods erect or ascending. 



Tall, 30-60 cm. high; plant somewhat glaucous; 



pubescence of 2-forked hairs. A. drummondii. 



Low, 10-30 cm. high; plant glabrous or somewhat 



stellate-pubescent below. A. lyallii. 



Arabis lyrata occidentalis Wats. Pubescent at base, glabrous above 

 stems branching from the base, ascending, 20-30 cm. high; basal leaves lyrate- 

 pinnatifid or sometimes nearly entire; cauline leaves spatula te to linear, 

 mostly entire; petals white; pods ascending or spreading, very slender, flat- 

 tened; stigma sessile or on a very short style; seeds oblong, wingless. 



Nooksack River, Whatcom County, Washington, Suksdorf. 



Arabis glabra (L.) Bernh. Biennial, pubescent near the base, glabrous and 

 glaucous above; stems usually simple, 60-90 cm. high; basal leaves oblanceolate, 

 dentate or pinnatifid, pubescent, 5-8 cm. long; cauline oblong-lanceolate, 

 sessile, sagittate and auricled at base, all but the lower glabrous; flowers whitish, 

 about 5 mm. long; pods erect or ascending, linear, 4-10 cm. long, tipped with 

 the large 2-lobed sessile stigma; pedicels 4—10 mm. long. 



Fields and open places, not rare. 



Arabis hirsuta (L.) Scop. Biennial, usually rough-hairy, but shade plants 

 often nearly glabrous; stems erect, 15—50 cm. high; basal leaves clustered, 

 oblanceolate, entire or somewhat dentate, usually 2—5 cm. long; cauline oblong, 

 to lanceolate, entire or dentate, cordate or auriculate at base; flowers greenish 

 white, small; pods on slender pedicels, erect, slender, 2-5 cm. long, tipped with 

 a very short stout style. 



On rocky cliffs or gravelly bars, infrequent. 



Arabis platysperma Gray. Perennial from a branched rootstock, finely 

 stellate-pubescent to nearly glabrous, glaucous; leaves all entire, the basal 

 oblanceolate and petiolate, 1 0-30 cm. high , the cauline oblong to lanceolate and 

 sessile; flowers rose-colored or white; pods erect or ascending, flattened, the 

 valves veiny, 3-6 cm. long, 3-5 mm. broad, tipped with a short style; seeds 

 circular, broadly winged. 



Mount Hood, Oregon, and southward in the mountains. 



Arabis olympica Piper. Perennial, sparsely pubescent with simple or 

 branched hairs ; basal leaves obovate to oblanceolate, obscurely crenate, obtuse, 

 petiolate, about 8 mm. long; cauline sessile, oblong to lanceolate, obtuse, 



