306 BRASSICACEAE 



7. Arabis olympica Piper. Olympic Rock-cress. Fig. 2103. 



Arabis olympica Piper, Contr. U.S. Nat. Herb. 16: 208. 1913. 



Arabis furcata var. olympica Rollins, Research Stud. St. Coll. Wash. 4: 19. 1936. 



Perennial with a stout, slightly branched caudex, the stems 5-10 cm. high, pubescent with 

 2-forked hairs. Basal leaves obovate to oblanceolate, more or less ciliate on the margins and 

 pedicels with simple hairs, otherwise glabrous or with a few forked hairs along the midrib, the 

 blade 5-10 mm. long, entire or slightly toothed, narrowed to a short winged petiole ; stem leaves 

 oblong to lanceolate, sessile, not auriculate, entire, pubescent on the margins and midrib ; sepals 

 2 mm. long ; petals white, equaling the sepals ; fruiting pedicels 3-6 mm. long ; pods erect, about 

 2 cm. long, 1 mm. wide, glabrous. 



Known only from the type locality, "on grass covered talus slopes at the base of Mt. Olympus, near 

 Hume's Glacier, 4,500 feet altitude," Washington. July-Sept. 



8. Arabis furcata S. Wats. Cascade Rock-cress. Fig. 2104. 



Arabis furcata S. Wats. Proc. Amer. Acad. 17: 362. 1879. 

 Arabis Suksdorfii Howell, Fl. N.W. Amer. 43. 1897. 



Perennial, with a cespitose caudex, the stems erect or ascending, 1-3 dm. high, glabrous. 

 Basal leaves ovate to oblong-lanceolate, 2.5-5 cm. long, sparingly toothed, often ciliate on the 

 margins, otherwise glabrous; stem leaves sessile, oblong to linear, entire or sparingly toothed; 

 petals white, 5—15 mm. long; pedicels 5-7 mm. long; pods 20-35 mm. long, attenuate to a rather 

 short style ; seeds oblong-elliptical, winged at the lower end. 



Rocky bluffs, Transition Zone; Cascade Mountains, Washington and Oregon. Type locality: "Bluffs of the 

 Columbia River, near the mouth of Hood River," Oregon. May-July. 



9. Arabis aculeolata Greene. Waldo Rock-cress. Fig. 2105. 



Arabis aculeolata Greene, Leaflets Bot. Obs. 2: 69. 1910. 



Perennial from a very slender rootstock, hirsute throughout with simple hairs, the stems 

 solitary or few, 10-15 cm. high, simple and slender. Basal leaves in a small rosulate tuft, ob- 

 ovate, spatulate to oblanceolate, 15-20 mm. long, entire or with a few teeth; stem leaves few, ob- 

 long, 5-6 mm. long, sessile, obtuse at apex; racemes short, few-flowered; calyx purple, 4 mm. 

 long; petals purple, 10-15 mm. long; fruit erect, 4-6 cm. long, 1.5 mm. wide, attenuate at apex. 



Rocky hillsides, Arid Transition Zone; Siskiyou Mountains near Waldo and Kirby, Josephine County, 

 Oregon. Type locality : near Waldo, Oregon. April-June. 



10. Arabis Cusickii S. Wats. Cusick's Rock-cress. Fig. 2106. 



Arabis Cusickii S. Wats. Proc. Amer. Acad. 17: 363. 1879. 



Biennial with a taproot and usually simple crown, the stems usually several, 1-2 dm. high, 

 simple, glabrate above, hirsute below with mostly simple hairs. Basal leaves linear-lanceolate, 

 2-3 cm. long, hirsute and ciliate; stem leaves linear to linear-oblong, sessile, not auriculate; 

 sepals villous; petals rose-colored, 6-10 mm. long; fruiting pedicels 10-14 mm. long; pods 

 arcuate-ascending, 5-7 cm. long, 3 mm. wide, obtusish, glabrous; stigma sessile; valves 1 -nerved 

 below the middle ; seeds in 1 row, orbicular, winged all around. 



On rocky ridges, Arid Transition Zone; Spokane County, eastern Washington, to northeastern Oregon. 

 Type locality: "on rocky ridges, Union County, Oregon." May-July. 



11. Arabis hirsuta (L.) Scop. Hairy Rock-cress. Fig. 2107. 



Turritis hirsuta L. Sp. PI. 666. 1753. 



Arabis hirsuta Scop. Fl. Cam. ed. 2. 2: 30. 1772. 



Arabis ovata Poir. in Lam. Encycl. Suppl. 5: 557. 1817. 



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



Stems erect, nearly simple, 3-6 dm. high, hirsute or nearly glabrous. Basal leaves with 

 margined petioles, obovate, dentate or repand, 2-5 cm. long; stem leaves sessile, auriculate, 

 lanceolate or oblong ; pedicels nearly erect to appressed, 6-12 mm. long in fruit ; petals greenish 

 white, 4-5 mm. long; pods narrowly linear, erect or appressed, 25-50 mm. long, about 1 mm. 

 wide ; style very short. 



In rocky places, Boreal and Austral Zones; Alaska to New Brunswick, California, and Georgia; also in 

 Europe and Asia. Type locality: Europe. May-Sept. 



12. Arabis Whitedii Piper. Whited's Rock-cress. Fig. 2108. 



Arabis Whitedii Piper, Bull. Torrey Club 28: 39. 1901. 

 Sandbergia Whitedii Greene, Leaflets Bot. Obs. 2: 136. 1911. 



Perennial, the branches few to several from a slender taproot, the flowering stems 2-5 dm. 

 high, simple or frequently branched, whole plant grayed with a coarse stellate pubescence. 

 Basal leaves oblanceolate, tapering to an elongated petiole, 4-6 cm. long, 4-6 mm. wide; stem 

 leaves oblanceolate, 2-3 cm. long, narrowed to the base, not auriculate; racemes becoming 

 elongated, many-flowered; fruiting pedicels very slender, 8-15 mm. long; sepals 3 mm. long, 

 stellate ; petals white, 5 mm. long ; pods 12-16 mm. long, 1 mm. wide ; seeds wingless. 



A locally distributed species known only from Wenatchee Flat, Kittitas County, and at the junction of 

 Wilson and Crab Creeks, Douglas County, Washington. May-June. 



