MUSTARD FAMILY 313 



stellate-pubescent, or glabrous above. Basal leaves 2-3 cm. long, broadly spatulate to narrowly 

 oblanceolate, dentate, the petioles somewhat ciliate; stem leaves sagittate at base; petals pale 

 rose, 4-5 mm. long ; fruiting pedicels spreading ; pods 4-6 cm. long, 1 . 5-2 mm. wide, arcuate ; 

 seeds in 1 row, orbicular, very narrowly margined. 



Drv plains and valleys, Arid Transition and Upper Sonoran Zones; eastern Washington and northern 

 Nevada to the desert ranges of southern California, east to Utah and Arizona. Type locality: from northern 

 Nevada and Utah to Arizona and the San Bernardino Mountains in California. April-June. 



31. Arabis atrorubens Suksdorf. Black-flowered Rock-cress. Fig. 2127. 



Arabis atrorubens Suksdorf ex Greene, Erythea 1 : 223. 1893. 



Arabis atriflora Suksdorf, Deutsch. Bot. Monatss. 16: 211. 1899. 



Arabis sparsiflora var. atrorubens Rollins, Research Stud. St. Coll. Wash. 4: 25. 1936. 



Stems erect, 3-8 dm. high, glabrous. Basal leaves oblanceolate, obtuse, dentate, scabrous- 

 pubescent; stem' leaves ovate to ovate-lanceolate, dentate or the upper entire, auriculately lobed; 

 sepals and pedicels puberulent; petals 8 mm. long, dark purple, almost black; fruiting pedicels 

 erect-spreading ; pods at first nearly erect but soon slightly arcuate and spreading, 8-12 cm. 

 long, 2-2.5 mm. wide, glabrous and nerveless; seeds in 1 row. 



Rocky places, Arid Transition Zone; Kittitas and Klickitat Counties, eastern Washington. Type locality: 

 western Klickitat County, Washington. April-May. 



32. Arabis Lemmonii S. Wats. Lemmon's Rock-cress. Fig. 2128. 



Arabis canescens var. latifolia S. Wats. Bot. King Expl. 17. 1871. 

 Arabis Lemmonii S. Wats. Proc. Amer. Acad. 22: 467. 1887. 

 Arabis latifolia Piper, Contr. U.S. Nat. Herb. 11: 295. 1906. 

 Arabis horisontalis Greene, Leaflets Bot. Obs. 2: 74. 1910. 

 Arabis polyclada Greene, op. cit. 2: 75. 



Perennial, with a short cespitose caudex, the stems several, 8-20 cm. high, slender, glabrous 

 or sparsely stellate-pubescent and glaucous above, hoary below with a fine densely stellate 

 pubescence. Basal leaves spatulate-oblanceolate, 12-18 mm. long, entire or rarely with 1 or 2 

 teeth ; stem leaves oblong-lanceolate, glabrous or nearly so ; petals rose-colored ; fruiting pedicels 

 2-6 mm. long, glabrous ; pods ascending or spreading, somewhat arcuate, 25-40 mm. long, 1 . 5-2 

 mm. wide, attenuate to the short style ; seeds orbicular, narrowly winged, in 1 row. 



Rocky ground, Boreal Zones; British Columbia and Montana to the southern Sierra Nevada, California. 

 Type locality: California, no definite locality mentioned. June-Aug. 



33. Arabis Breweri S. Wats. Brewer's Rock-cress. Fig. 2129. 



Arabis Breweri S. Wats. Proc. Amer. Acad. 11: 123. 1876. 



Perennial with a cespitose woody caudex, the stems several, 5-20 cm. high, villous with 

 usually 2-3-forked hairs, or stellate below. Basal leaves 6-20 mm. long, oblanceolate, entire or 

 few toothed, finely stellate-pubescent, the petioles ciliate ; upper stem leaves lanceolate to nar- 

 rowly oblong, obtusely auriculate or subcordate at base, somewhat pubescent, villous or glabrate ; 

 sepals tinged with purple, pubescent; petals deep rose-purple to nearly white, 6-8 mm. long; 

 fruiting pedicels 5-8 mm. long, pubescent ; pods at length spreading and more or less arcuate, 3-7 

 cm. long, 2 mm. wide, acute ; stigma sessile ; seeds orbicular, narrowly winged, in 1 row. 



Rocky summits of mountain peaks, mainly Arid Transition Zone; California Coast Ranges, Siskiyou County 

 to Santa Clara County. Type locality: Mount Diablo, California. April-June. 



34. Arabis Koehleri Howell. Koehler's Rock-cress. Fig. 2030. 



Arabis Koehleri Howell, Fl. N.W. Amer. 44. 1897. 



Cespitose perennial, with a woody much branched caudex; flowering stems several, simple, 

 5-25 cm. high, glabrous or sparsely pubescent with forked hairs. Basal leaves rosulate, 

 numerous, 1-2 cm. long, linear-lanceolate to oblanceolate, acutish, entire, cinereous with a 

 dense stellate puberulence; stem leaves lanceolate, auriculate-clasping, 1-2 cm. long, sparsely 

 pubescent with forked hairs ; sepals oblong, 3-4 mm. long, purple, glabrous except for a few 

 scattering stellate hairs above; petals spatulate, 8-10 mm. long, deep reddish purple; pedicels 

 slender, 1-2 cm. long ; pods erect-spreading and arcuate, 5-8 cm. long, 1 . 5-2 mm. wide, glabrous, 

 narrowed at apex ; seeds in 1 row, narrowly wing-margined. 



Rocky cliffs, Transition Zone; western Oregon, from Douglas County to Josephine County. Type locality: 

 bluffs along the Umpqua River, Roseburg, Oregon. March-April. 



35. Arabis sparsiflora Nutt. Elegant Rock-rose. Fig. 2131. 



Arabis sparsiflora Nutt. in Torr. & Gray, Fl. N. Amer. 1 : 81. 1838. 



Arabis arcuata var. subvillosa S. Wats, in A. Gray, Syn. Fl. N. Amer. 1 J : 164. 1895. 



Arabis elegans A. Nels. Bot. Gaz. 30: 192. 1900. 



Arabis perelegans A. Nels. in Coult. & Nels. Man. Bot. Rocky Mts. 228. 1909. 



Biennial or short-lived perennial, the stems solitary or few from the root crown, 5-7 dm. 

 high, glabrous to sparsely hirsute with mostly simple hairs. Basal leaves oblanceolate, 4-5 

 cm. long with a few serrate teeth, pubescent on both surfaces with few-forked hairs; stem 

 leaves linear-lanceolate, auriculate-clasping, sparsely hirsute; racemes becoming much elongated 

 in fruit; pedicels 5-10 mm. long, villous; corolla 12-15 mm. long, pale to dark purple; pods 



