74 LEAFLETS. 



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Collected at several stations in northwestern Wyoming, by 

 N. Rose, late in August, 1893 ; the type his n. 399^ 

 The rosettes of basal leaves, all so very small, resemble some 

 sedumsand saxifrages, while those of the stem recall the cord- 

 ate bracts of certain streptanthoids. 



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Arabis semisepulta. Perennial, low, the whole when in 

 fruit only 3 or 4 inches high ; subterranean parts consisting of 

 a tap root and hypogeous branches, these each ending in a tuft 

 of leaves ^ to ^ inch long, firm, whitish with a dense stellate 

 tomentum, the blade ovate, tapering to a long wnde petiolar 

 base; cauline leaves sessile, without auricles, these and the stem 

 strongly stellate-pubescent : flowers not known : fruiting 

 racemes short, of 6 to 10 narrow obtuse almost horizontally 

 spreading but curved pods about 1^ inches long, not tapering 

 to either end : seeds round-oval, wingless and marginless. 



Mt. Thielson, Cascade Range, Oregon, near the summit: in 

 loose lava gravel, collected by Coville and Applegate, 6 Aug., 

 1897; their n. 454 as in U. S. Herb. . 



Arabis horizontaus. Perennial, the stout and deep tap 

 root supporting at summit a few short subligtieous branches, 

 with tufts of leaves and several ascending flowering branches, 

 the whole 6 to 10 inches high : basal leaves of very firm tex- 

 ture, an inch long, oblanceolate, acute, entire, finely stellate 

 and hoary; flowering stems floriferous from near the base, but 

 the cauline leaves not few% closely approximate, H inch long, 

 oblong-oval, sessile, shortly auricled, greener than the basal 

 and only sparsely stellate: flowers small, only 2 lines long; 

 petals purple, twice the length of the oval glabrous purple- 



margined sepals : 



H to I'A 



long, quite broad in the middle portion but tapering gradually 

 to both ends, therefore lance-linear ; horizontally spreading 

 on short rigid pedicels : body of seed round-oval, but the seed 

 as a whole orbicular by virtue of the broad encircling wing. 



Crater Lake, Klamath Co., Oregon, 1 Aug., 1897, Coville 

 and Applegate ; their n. 334 as in U. S. Herb. 



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