260 PROCEEDINGS OP THE AMERICAN ACADEMY 



Draba Breweri. Dwarf and alpine, biennial or a short-lived 

 perennial, the very shortly branched caudex sending up 2 to 6 or 

 more simple leafy stems 1 to 3 inches high, canescent throughout 

 with a hue dense stellate pubescence : basal leaves crowded, oblong 



late to ovate: pods oblong to lanceolate, usually acute and flat, glabrous or 

 finely pubescent, usually suberect on ascending pedicels ; style very short. — 

 D. contorta and D. confusa, Ehrh. Greenland to Labrador, New Brunswick and 

 northern Vermont, and in the Rocky Mountains to Colorado and British Colum- 

 bia. Europe and Asia. Most western specimens are more finely and densely 

 pubescent than is usual. 



Var. arabisans. Caudex much branched : pod glabrous, acuminate or acute, 

 often twisted ; style longer. — D. arabisans, Michx. D. Canadensis, Brunet, a form 

 with ovate pods. Labrador to northern Vermont and the shores of the Great 

 Lakes. Grading indefinitely into the typical form. 



28. D. Breweri, Watson. See above. 



29. D. borealis, DC. Loosely stellate-pubescent throughout, more or less 

 cespitose : leaves ovate to oblong-ovate : pods broad, ovate to oblong ovate, 

 flat, exceeding the pedicels; style short and stout. — D. Unalaschkiana, DC. 

 D. incana, var. borealis, Torr. & Gray. Alaska and adjacent islands to British 

 Columbia and the northern Arctic coast. Kamtchatka. A variety with longer 

 pedicels (D. Sachalinensis, Schmidt) is found in Japan. 



= = Cauline leaves usually one to three. 



30. D. hirta, Linn. Loosely and often sparingly stellate-pubescent : caudex 

 branched : leaves narrowly oblanceolate, or the cauline ovate, frequently more 

 or less ciliate : pods oblong-lanceolate to -ovate, often twisted, glabrous or 

 sparingly pubescent; style short and stout. — D. oblongata and D. rupestris,"R. Br. 

 D. gracilis, Ledeb. Greenland to Alaska. Northern Europe and Asia. 



Var. arctica. Densely tufted and more densely pubescent: leaves short, 

 the cauline ovate: pods pubescent. — D. arctica, Vahl. Greenland and Grin- 

 nell Land ( Greeley). Spitzbergen. 



++ ++ Stems diffusely branched above. 



31. D. ramosissima, Desv. Thinly stellate-pubescent, the caudex much 

 branched : leaves oblanceolate, laciniately toothed : pods oval to narrowly ob- 

 long, pubescent, twisted; style long and slender. — Mountains of Virginia and 

 Tennessee ; cliffs of Kentucky River. 



§ 5. Aizopsis, DC. Scapose cespitose perennials: leaves linear, entire, be- 

 coming more or less rigid, carinate : flowers yellow. 



32. D. glacialis, Adams. Alpine or subalpine : leaves linear or linear- 

 oblanceolate, more or less loosely (or densely) stellate-pubescent, sometimes 

 ciliate at base: pods ovate to ovate-oblong, acute (rarely narrowly oblong and 

 acute at both ends), usually finely pubescent ; style short. — D. oligosperma, Hook. 

 D. alpina, var. glacialis, Dickie. From the arctic regions to Colorado, Utah, 

 and California. Siberia and Spitzbergen. Quite variable. 



Var. pectinata. Alpine and very densely cespitose, the short rigid leaves 

 glabrous or nearly so and ciliate with long rigid hairs. — ■ D. densifolia, Nutt. 

 From northern Utah to the Sierra Nevada. 



