Draba. CRUCIFER^. 107 



of Lake Superior, Dr. Pitcher ! — Stems many from a single root, 6-8 inches 

 high. Radical leaves numerous, forming a rosulate tuft, 1-U inch long, 

 acute, much attenuated at the base, furnished with 2 (rarely more) very acute 

 spreading teeth on each side, sometimes entire; cauUne leaves somewhat 

 clasping! Flowers in a short close nearly simple raceme. Petals broadly 

 ovate. Silicle half an inch long, contorted; cells about 10-seeded: lower 

 pedicels nearly as long as the silicle ; upper ones shorter, often cohering by 

 pairs nearly or quite to the summit.— Nearly related to D. incana, and also to 

 D. hirta. We have seen in the herbarium of the Academy at Philadelphia, 

 si)ecimens of the var. 0. ; but the locality is not recorded. 



♦♦* Annual or biennial : stems leafy. 



20. D. incana (Linn.) : stem leafy, simple or branching, clothed with a 

 velvety stellate pubescence ; leaves ovate, toothed ; silicles oblong, glabrous 

 or pubescent, contorted or straight. 



a. cauline leaves ovate, acutely toothed ; silicles mostly contorted, gla- 

 brous ; style very short.— D. incana, Fl. Dan. t. 130 ; Pursh, fi. 2. p. 434 ; 

 Hook.fl. Hor.-Am. 1. p. 54. D. contorta, Ehrh.; DC. prodr. I. p. 170. 



p. confusa : leaves sparingly toothed ; silicles pubescent. — D. mcana, var. 

 Linn. D. confusa, Ehrh. ; DC. prodr. I. c. ; Hook. '. fl. Bor.-Am. 1. p. 54. 



y. borealis : somewhat hirsute ; stem-leaves few, ovate ; radical ones ob- 

 long, attenuate at the base, entire ; silicles . . . (ovaries ovate) — D. borealis, 

 DC. syst. 2. p. 342. (fide Hook.) 



a. Labrador. 0. Arctic America and the Rocky Mountains, y. Islands of 

 St. Lawrence and Unalaschka.— @ and Ij? Stems 6-10 inches high, usually 

 sev.eral from one root. Raceme somewhat compound. Hook. 



21. D. glabella (Pursh) : slightly and somewhat stellately pubescent ; radi- 

 cal leaves oblong-spatulate ; cauline ones 2-4, ovate, toothed or entire; petals 

 (white) naore than twice as long as the very smooth calyx ; silicles. . . Hook. 

 — Pursh, fl. 2. p. 434? ; Richards, app. Frankl. jour. ed. 2. p. 27 ; Hook, 

 fl. Bor.-Am. 1. p. 54. 



Margins of alpine rivulets in the Rocky Mountains, between lat. 52^-57='. 

 Hudson's Bay, Pursh.— Uahit of D. crassifolia, but 3-4 times the size, and 

 the flowers as large as any of the genus. Silicles not seen. Hook. 



22. D. Unalaschkiana (DC): stem leafy, simple, pubescent; leaves 

 ovate-oblong, entire, pubescent ; silicles oblong, minutely hirsute. DC. syst. 

 2. p. 3S0 ; Hook. fl. Bor.-Am. 1. p. 55. 



Unalaschka.— Petals (white) twice as long as the calyx ; lamma obovate, 

 emarginate. DC. 



23. D. aurea (Vahl) : pubescent ; stem erect, leafy ; leaves lanceolate or 

 ovate-lanceolate, acute, entire or toothed ; corymbs terminal and axillary ; 

 silicles oblong-lanceolate, pubescent, 3 times as long as the pedicels ; petals 

 (yellow) emarginate; style rather short. Hook.—Fl. Dan. t. 1460; DC. 

 prodr. 1. p. 170; Hook.fl. Bor.-Am. 1. p. 55, f in hot. mag. t. 2934. 



Rocky Mountains. — Flowers sometimes white. Hook. 



24. D. lutea (Gilib.) : pubescent; stem branching, leafy; leaves oval; 

 cauline ones lanceolate, toothed ; silicles oblong-elliptical, glabrous, about 30- 

 seeded, one-third the length of the pedicels. Hook.— DC. prodr. 1. p. Ill ; 

 Hook. ft. Bor.-Am. I. p. bb. , . , .,. i tt i 



fi. lonsripes (DC.) : pedicels 3-4 times the length of the siUcles.— l/oo/i:. 

 I. c— D.^gracilis, Graham^ in Edinb. phil. jour. 1828. p. 172. 



Arctic and Subarctic America ! Grassy moist places at the junction of the 

 Wahlamet and the Oregon, Nuttall /—Stem 6-15 inches high, very slender, 



