314 BRASSICACEAE 



arcuately spreading, 6-10 cm. long, 1.5 mm. wide, midvein obscure; stigma sessile; seeds in 1 

 row, narrowly winged all around. 



Rocky places, Arid Transition and Upper Sonoran Zones; Columbia Basin, eastern Washington, to the 

 Klamath Basin, northeastern California. Type locality : "Forests of the Rocky Mountains towards the sources 

 of the Oregon." April-June. 



36. Arabis campyloloba Greene. Modoc Rock-cress. Fig. 2132. 



Arabis campyloloba Greene, Pittonia 4: 192. 1900. 

 Arabis arbuscula Greene, Leaflets Bot. Obs. 2: 77. 1910. 



Short-lived perennial, the stems solitary or few from an unbranched, not at all woody crown, 

 4-6 dm. high, sparsely stellate-pubescent. Basal leaves oblanceolate, toothed or entire, densely 

 stellate-pubescent ; stem leaves linear-lanceolate, revolute, sagittate-clasping ; fruiting pedicels 

 divaricate, 4-6 mm. long, loosely stellate-pubescent ; pods glabrous, arcuate, 4-8 cm. long, 2 mm. 

 wide. 



On gravelly slopes, mainly Arid Transition Zone; Grant County, eastern Oregon, to northeastern Califor- 

 nia, and adjacent Nevada. Type locality: near Yreka, California. May-July. 



37. Arabis maxima Greene. Arched Rock-cress. Fig. 2133. 



Streptanthus arcuatus Nutt. in Torr. & Gray, Fl. N. Amer. 1: 77. 1838. 



Arabis arcuata A. Gray, Proc. Amer. Acad. 6: 187. 1863. Not Shuttlw. 1852. 

 Arabis maxima Greene, Pittonia 4: 192. 1900. 



Arabis Holboellii var. arcuata Jepson, Man. Fl. PI. Calif. 430. 1925. 



Perennial, stellate-pubescent throughout, the stems several, erect from a branching caudex, 

 4-8 dm. high, simple or branched. Basal leaves 25-60 mm. long, narrowly oblanceolate, acute, 

 entire or repand-dentate, their petioles often ciliate ; stem leaves linear to lanceolate, mostly 

 entire; petals 6-12 mm. long, rose-colored; fruiting pedicels divaricate or recurved, 6-12 mm. 

 long ; pods arcuate, 5-7 cm. long, 2-3 mm. wide, acute ; seeds orbicular, narrowly winged, as 

 broad as the valves. 



Rocky or gravelly ridges, Arid Transition Zone; South Coast Ranges and central Sierra Nevada, Cali- 

 fornia, to northern Lower California. Type locality: "Shelving rocks on high hills near Santa Barbara," 

 California. March-May. 



38. Arabis Hoffmannii (Munz) Rollins. Hoffmann's Rock-cress. Fig. 2134. 



Arabis maxima var. Hoffmannii Munz, Man. S. Calif. 205. 1935. 

 Arabis Hoffmannii Rollins, Madrono 3: 360. 1936. 



Perennial, the stem solitary or usually several from the woody caudex, 5-7 dm. high, gla- 

 brous or sparsely pubescent with forked hairs toward the base, simple or branched above. 

 Lower leaves crowded, linear-lanceolate, sinuate-dentate or entire, 5-10 cm. long, coriaceous, 

 pubescent with forked hairs ; stem leaves sessile and auriculate, glabrous above, pubescent beneath ; 

 sepals 4-5 mm. long, glabrous or nearly so ; petals linear-oblong, 4-5 mm. long, white ; fruiting 

 racemes 2-4 dm. long ; pedicels ascending, 1-4 cm. long ; pods ascending, straight or becoming 

 slightly arcuate, 5-10 cm. long, 2-3 . 5 mm. wide, glabrous and nerveless ; styles short and stout ; 

 seeds in 2 rows, 1 mm. wide, narrowly winged. 



Rocky ridges and cliffs, Upper Sonoran Zone; Santa Cruz Island, southern California. Type locality: sea 

 cliffs east of Dick's Harbor. Feb.-April. 



39. Arabis rectissima Greene. Bristly-leaved Rock-cress. Fig. 2135. 



Arabis rectissima Greene, Pittonia 4: 191. 1900. 

 Arabis setigera Greene, Leaflets Bot. Obs. 2: 80. 1910. 

 Arabis Wyndii Henderson, Rhodora 32: 25. 1930. 



Perennial, stems few from the root-crown, 4-5 dm. high, strictly erect, glabrous and glaucous, 

 except for scattering 2-forked hairs near the base. Basal leaves oblanceolate, about 2 cm. long, 

 ciliolate on the margins and somewhat setulose with simple and 2-3-f orked hairs ; stem leaves 

 sessile, sagittate, oblong, 15-20 mm. long, the lower setulose, the upper glabrous; sepals 2.5 mm. 

 long; petals white tinged with rose-purple, 4 mm. long; fruiting racemes 2-3 dm. long; pedicels 

 reflexed, glabrous or thinly stellate-pubescent ; pods strongly refracted, straight, 4-7 cm. long, 

 2-2.5 mm. wide, acute at apex, glabrous, the valves 1 -nerved toward the base; seeds in 1 row, 

 orbicular, narrowly winged all around, 1.5-1.7 mm. broad. 



Open pine forests and edges of mountain meadows, Arid Transition Zone; Cascade Mountains, Klamath 

 County, Oregon, to the southern Sierra Nevada, California. Type locality: middle elevations of the mountains 

 of Fresno County, California. June-July. Rector's Rock-cress. 



40. Arabis Holboellii Hornem. Holboell's Rock-cress. Fig. 2136. 



Arabis Holboellii Hornem. Fl. Dan. 2: 5. pi. 1879. 1827. 

 Arabis retrofracta Graham, Edinb. New Phil. Journ. 344. 1829. 

 Turritis retrofracta Hook. Fl. Bor. Amer. 1: 41. 1829. 



Biennial or perennial, the stems simple or branched, 3-5 dm. high, stellate-pubescent below. 

 Basal leaves oblanceolate, 1-3 cm. long, entire, densely stellate-pubescent ; stem leaves lanceolate, 

 entire, sagittate at base, sparsely stellate-pubescent or the upper glabrous ; sepals stellate- 

 pubescent ; petals 6-8 mm. long, white or rose-colored; fruiting pedicels 1 cm. long, reflexed; 

 pods straight, 4-8 cm. long, 1 . 5-2 mm. wide, obtuse at apex, glabrous ; seeds orbicular, nar- 

 rowly winged, in 2 rows in each cell. 



Usually gravelly or rocky places. Boreal Zones; Alaska to Greenland, south to Washington, Lake Superior, 

 and Quebec. In Washington it is found in the Cascade Mountains as far south as Mount Rainier. Type 

 locality: on rocks, Disco Island, Greenland. June-Aug. 



