42 CRUCIFER. : ARABIS,: 
6 ARABIS L.. Gen. n. 818. sou a ab 
Annual biennial or perennial herbs, rarely suffrutescent at base 
with usually simple leaves, stellate. or forked pubescence, and 
white or purple flowers in ebracteate racemes. Sepals equal or 
the lateral ones saccate at base. Petals entire or emarginate, 
usually unguiculate. ‘Stamens 6, free and unappendaged. Pods 
linear compressed parallel to the partition, with flat or subcon- 
vex, more or less prominently 1-nerved valves and membranace* 
ous partition. Stigma simple or barely 2-lobed. Seeds in 1-2 
rows: elliptical or orbicular, more or less margined or winged. 
Cotyledons accumbent or oblique. : 
§ 1 StsymprinA Watson in Gray Syn. Fl. i, 159. Bienni- 
als or perennials with the pubescence, if any, wholly simple 
above, but forked upon the lowest leaves. 
A. Nuttallii Robinson in Gray Syn. Fl. i, 160. A. spathulata Nutt. T. & 
G. Fl. i, 81, not DC. Stems slender simple, 6-10 inches high from a 
branching biennial or perennial rootstock, erect-or ascending, glabrous 
~ above, more or less hirsute below: radical leaves spatulate-oblanceolate, 
obtuse or acutish, entire, an inch or less long: cauline narrowly oblong to 
elliptical, sessile but not auricled: petals 2-3 lines long, white: pods short, 
6-9 lines long by % of a line broad, somewhat attenuate toa rather stout 
style: valves slightly convex, 1-nerved and faintly veined: seeds elliptical: 
cotyledons accumbent.. On low grounds, mountains of eastern Washing- 
ton and western Montana. . 
§ 2 Turriris Flowers whitish; pods narrow: seeds in 2 rows 
in the cells. 
A. perfoliata Lam. Encycl. i, 219. Glaucous, stems erect, solitary, sim- 
ple or sparingly branched, usually stout, 1-6 feet high from a biennial 
root: radical leanes spatulate, 2-4 inches long, sinuate-pinnatifid or 
toothed, ciliate and more or less hirsute with stellate hairs; cauline leaves 
entire ovate to ovate-lanceolate, clasping by the sagittate base: raceme 
long and strict: flowers white or stramineous: petals linear-lanceolate, 2— 
3 lines long, not more thau twice the length of the sepals: pods strictly 
erect almost terete, 3-4 inches long, less than a line wide, on short pedi- 
cels: style short or none, stigma 2-lobed: seeds somewhat in 2 rows nar- 
rowly winged or wingless: cotyledons accumbent to incumbent in the 
same pod. On dry ridges and stony hillsides, Brit. Columbia to Califor- 
nia and across the continent to New England and New Jersey. 
§ 3 Evarasis Watsonin Gray Syn. Fl. i, 160 in part. Seeds 
orbicular or broadly elliptical, more or less wing-margined. Coty- 
ledons strictly accumbent. 
A. hirsuta Scop. Fl. Carn. ed. 2, ii, 30... More-or less hirsute at least at 
the base with spreading simple or forked, rarely stellate hairs: stems often 
clustered on the crown of the biennial root or branching caudex, 6-20 
inches high, simple or with slender strict branches above: radical leaves in 
a rosulate cluster, ovate to spatulate attenuate to a winged petiole, entire 
or sparsely dentate; cauline ones ovate to oblong or lanceolate sessile and 
partly clasping by a somewhat sagittate or cordate base: petals white, 
spatulate twice as long as the greenish sepals: pods strictly erect 1-2 
inches long, less than a line wide on erect slender pedicels; style very 
short and stout or the stigma nearly sessile: seeds suborbicular, very nar- 
rowly winged. In moist places, Sierra Neyadas of California through Ore- 
gon and Washington to northern Alaska and across the continent to the 
