Draba. CRUCIFERiE. 103 



mostly entire ; silicles large, inflated, didymous ; seeds not margined.— //oofr, 

 //. Bor.-Am. 1. p. 49. t. IG. 



In deep sand on the Rocky Mountains, lat. 52^-57, Drummond ! and on 

 the Argillite hills of the Platte, from Scott's Bluffs to the mountains, Nut- 

 tall! Oregon, Douglas, Nidtall.— U Root fusiform. Stems branching 

 from the base, diffuse, 3-4 inches high. Flowers showy, corymbed. Petals 

 obovate-spatulate, nearly twice as long as the calyx. Silicle conspicuously 

 didymous ; each cell of the size of a large pea : septum lanceolate ! 



22. ALYSSUM. Linn, (in part); DC. syst. 2. p. 301. 



Silicle orbicular or elliptical ; valves plane or convex in the centre. Seeds 

 2-4 in each cell, compressed, sometimes membranaceously margined. Calyx 

 equal at the base. Petals entire. A part of the stamens usually toothed. 



1. A. hyperboreum (h'lnn.): stems herbaceous, caespitose ; leaves ellipti- 

 cal, coarsely and acutely toothed, somewhat hirsute; silicles elliptical; the 

 longer stamens toothed. DC.—Pursh, Ji. 2. p.i3i; DC. prodr. 1. p. 164. 

 Draba hyperborea, Dcsv. 



N. W. Coast.— A doubtful native of America. 



23. DRABA. Linn.; R. Br. inhort. Kew. 4. p. 91. 

 Draba & Erophila, DC. 



Silicle oval or oblong ; valves plane or convex. Seeds many, not margin- 

 ed. Calyx equal. Petals entire or bifid. Stamens aU toothless. — Flowers 

 white or yellow. 



§ 1. Petals entire. — Draba, DC. 

 * Perennial: scapes mostly leafless. 



1. D. algida (Adams): flaccid; scapes short, naked, pilose with spreading 

 hairs; leaves oblong, plane, and (with the calyx) pilose with simple hairs; 

 silicles somewhat corymbed, elliptical, glabrous ; style very short ; flowers 

 yellow. Hook.— DC. prodr 1. p. 167 ; Hook. fl. Bor.-Am. 1. p. 50. 



y. hrachycarpa (DC.) : silicle shorter, ovate. — DC. I. c. 



S. breviscapa (Hook.) : scape immersed among the smoothish leaves. 

 Hook. I. c. 



Sea-coast of Arctic America. — Pedicels always glabrous. Petals obovate, 

 twice the length of the calyx. — Very near D. alpina. Hook. 



2. D. alpina (Linn.) : somewhat rigid ; scapes naked, mostly somewhat 

 hirsute ; leaves spatulate-lanceolate, plane, more or less pilose with branching 

 hairs; petals (yellow) more than twice the length of the calyx; silicles some- 

 what corymbed, oblong-elliptical ; style very short. — Fl. Dan. t. 56 (leaves 

 broader than in our plant) ; DC. prodr. 1. p. 67 ; R. Br. ! in Parry's 1st 

 voy. app. p. 265 ; Hook. ! fl. Bor.-Am. 1. p. 50. 



a. silicles glabrous. — D. alpina, herb. Linn, ex R. Br. I. c. 

 P. silicles hairy. — R. Br. I. c. 

 ^. flowers white.— flbofc. I. c. 



