Il6 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. 



Cauline leaves auriculate; plant glaucous, glabrous except 



near the base. A. glabra. 



Cauline leaves not auriculate; plant green, glabrous above, 



pubescent towards the base. A. nuUalUi. 



Seeds winged or wing-margined. 



Flowers white; seeds in a single row. A. hirsuta. 



Flowers red or pink; seeds in two rows. 



Cauline leaves not auriculate or cordate; leaves all 



entire, villous-hirsute. A. cusickii. 



Cauline leaves auriculate or cordate. 

 Radical leaves dentate. 



Pods curved, spreading; whole plant coarsely 



stellate-pubescent. A. sparsiflora. 



Pods straight, reflexed; plant finely stellate- 

 pubescent. A. holhoellii. 

 Radical leaves entire. 



Pods reflexed; herbage covered with a fine dense 



white stellate pubescence. A. puherula. 



Pods erect or nearly so; herbage green, glabrous 

 above. A. lyallii. 



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. Low ground, 

 not common. 



Arabis nuttallii Robinson. Perennial with branching rootstocks; stems 

 erect or ascending, simple, lS-25 cm. high, glabrous above, somewhat hirsute 

 below; radical leaves oblanceolate, acutish, sinuate-dentate, 1-2 cm. long; 

 cauline oblong to elliptical, sessile; flowers rather large in a short raceme; 

 petals 5-6 mm. long; pods erect, 12-16 mm. long, beaked with a stout style; 

 valves 1-nerved. In moist grassy meadows. 



Arabis hirsuta Scop. Biennial, usually rough-hairy, but shade plants often 

 nearly glabrous; stems erect, 15-50 cm. high; basal leaves clustered, oblan- 

 ceolate, 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 verj' short stout style. On rocky clifi^s or gravelly bars, infrequent. 



Arabis cusickii Wats. Biennial, roughly hirsute throughout with simple 

 hairs or somewhat glabrous above; stems usually several, 10-20 cm. high; 

 radical leaves oblanceolate, about 2 cm. long; cauline linear-oblong, sessile; 

 pods curved, ascending or spreading, glabrous, 5-8 cm. long; valves 1-nerved 

 below the middle. On basalt outcroppings, rather rare. 



Arabis sparsiflora Nutt. (Arabis arcuata subvillosa Wats.) Perennial 

 roughly stellate-pubescent below, glabrous above; stems mostly simple, erect 

 30-60 cm. high; radical leaves linear, oblanceolate, dentate, petioled; cauline 

 lanceolate, subentire, sessile, with a sagittate base; flowers rose-colored; pods 

 recurved, 5-8 cm. long, linear, acute; pedicels pubescent, 6-12 mm. long. 

 Basalt ledges, common. 



