68 CRUCIFERAE 



rare in the ropion of eastern Oregon, though obscurely known as occurring in northeastern Cali- 

 fornia. Our description is based primarily on a part of the original collection of Nuttall as 

 preserved in the Kew IIerl);iriuin, the lalul, "Aral)is canescens. R. Mts.," being in the hand of 

 Nuttall. He also collected it in the Blue Mts., Ore. (Syn. Fl. l':l(JG). The narrow pods and 

 the tufts of small whitish leaves make a distinctive impression upon the mind but arc difficult 

 to define in differential terms. Arabis canescens is allied to A. retrofracta Graham, but its 

 pods are narrower and much Hatter than in the latter species. 



Logs.— Eagle Peak, Warner Mts., L. S. Smith 815. Ore. : Dry Creek, Crook Co., Leiberg 3421. 



Refs.— Arabis canescens Nutt.; T. & G. Fl. 1:83 (1838), type loc. n. Rocky Mta., Nuttall; 

 Gray, Syn. Fl. r:165 (1895). 



15. A. beckwithii Wats. Lieutenant's Rock-cress. Stems 1 or few from a 

 simple or branched biennial root-crown, erect, simple or paniculately branching 

 above, 5 to 12 inches high, rather densely leafy; herbage hoary with a fine dense 

 pubescence, the inflorescence tending to be glabrous or glabrate; leaf-blades oblong- 

 or linear-lanceolate, entire or dentate, y2 to 1 inch long, the cauline leaves sessile, 

 the basal narrowed to a slender petiole ; raceme comparatively few-flowered and 

 soon loose; pedicels glabrous or scantily pubenilent; sepals slightly over half as 

 long as the petals; petals purple, 31/2 to 4 lines long, the limb obovate; pods 11/2 to 

 2% inches long, % to 1 line wide, glabrous, straight or somewhat curved, more or 

 less pendent on recurved or defiexed pedicels 2 to 3 (or 4) lines long. 



Rocky slopes, 4000 to 7600 feet : east side of the Sierra Nevada crest from Inyo 

 Co. to Modoc Co. East to Nevada, north to eastern Oregon. June. 



Tax. note. — The difficulties in distinguishing this species from A. retrofracta are often con- 

 siderable. Typically the stem in A. beckwithii is densely leafy and the stellate-pubescent herbage 

 inclines to be silvery in aspect, while the stem in A. retrofracta is much less leafy and the herbage 

 tends somewhat to green or greenish. 



Locs. — Goose Lake, C. C. Bruce 2247; Warner Mts., L. S. Smith 55; Parker Creek, Modoc 

 Co., Ferris # Duthie 65; Castle Peak, Sonne 6598; White Mts., Purpus 5796. Ore.: Redmond, 

 Deschutes Co., Whited 99. In the North Coast Ranges we find certain plants resembling A. beck- 

 withii and hesitantly note them as follows: Mt. Eddy, Heller 13,434; South Yollo BoUy, Jepson 

 13,342. 



Refs. — Arabis beckwithu Wats. Proc. Am. Acad. 22:467 (1887), type loc. Quartz Mts., 

 n. Nev., BecTcwith 22, the first cited collection. The second ("Carson City, Watson") and third 

 ("Candelaria, Shochley") collections cited by Watson we include in the species, excluding "San 

 Bernardino Mountains, Parish Brothers 1302". A. subpinnatifida var. bechwithii Jepson, Man. 

 431 (1925). 



16. A. rectissima Greene. Rector's Cress. Stems 1 to several, simple, aris- 

 ing from the crown of a biennial root, 1^/4 to 3 feet high; herbage a little glaucous, 

 pubescent below with simple or forked hairs or subglabrous and the leaves merely 

 ciliate; blades of basal leaves oblanceolate to obovate, contracted below to a winged 

 petiole, % to IV2 inches long; blades of cauline leaves linear or oblong-lanceolate, 

 sessile-auriculate, i/^ to 1^4 inches long; corolla white or pinkish-white, 2 to 3 lines 

 long; pods straight or very slightly curved, secund, deflexed or typically rather 

 closely reflexed, 2^4 to 3 inches long; pedicels glabrous, 3 lines long; seeds broadly 

 winged. 



Loose soil on mountain slopes or open forest floors, 3500 to 9000 (or 11,000) 

 feet: Sierra Nevada from Siskiyou Co. to Tulare Co.; San Bernardino Mts.; San 

 Gabriel Mts. June. See note under no. 12. 



Locs. — Black Butte near Mt. Shasta, Jepson 59e; Eagle Lake, Lassen Co., J. Grinnell; 

 Tahoe, K. Brandegee; Nevada Fall, Jepson 3139; Yosemite, Jepson 10,450; Lamberts Dome, 

 Mason 344; Huntington Lake, Jepson 12,992, 13,050, 13,078, 13,110; Evolution Basin, E. Fergu- 

 son 472; Bubbs Creek, Fresno Co., Jepson 812; Farewell Gap, Jepson 1004; Bear Valley, San 

 Bernardino Mts., Abrams 2830; Mt. San Antonio, Parish 1970. 



Refs. — Arabis rectissima Greene, Pitt. 4:191 (1900), type collected by L. A. B. PecTcinpah 

 in the Sierra Nevada, almost certainly near the Peckinpah Mill, 5600 feet alt., now Madera Co. 

 (formerly Fresno Co.). A. holboelUi var. fendleri Wats.; Gray, Syn. Fl. r:164 (1895) as to 

 California plants; not A. fendleri Greene, Pitt. 3:156 (1897). A. holboelUi var. fendleri Jepson, 



