MUSTARD FAMILY 93 



short or slender ; stigma simple or very slightly lobed. Pod oval to oblong or linear- 

 oblong, flat; partition thin-membranous. Seeds in 2 rows, neither margined nor 

 winged. Cotyledons accumbent or rarely incumbent. — Species 150, all continents 

 except Australia, but mostly arctic or alpine, the plant body, therefore, reduced 

 and often very variable. (Greek drabe, a name of Dioscorides for some cress.) 



A. Annuals; low altitudes (except no. 5). 



Flowers seeund, on reflexed pedicels; pods short, twisted l.D.unilateralis. 



Flowers not seeund. 



Petals not entire ; pods straight or nearly so. 



Petals deeply 2-cleft; corolla white; pods glabrous 2. D. verna. 



Petals retuse. 



Little exceeding the sepals; corolla yellowish, becoming white; pods puberulent 



3. D. nemorosa. 

 Nearly twice as long as the sepals; corolla white; pods pubescent or glabrous 



4. D. cuneifolia. 

 Petals entire, obtuse or truncate; corolla yellow; pods glabrous, usually a little curved 



5. D. stenoloba. 



B. Perennials; alpine or subalpine plants with branched densely leafy root-crown. 



Leaves not carinate, soft. 

 Style l^ to % line long. 



Flowers yellow ; leaves loosely or thinly pubescent or ciliate. 



Flowering stems conspicuously leafy ; leaf -blades oblong-linear ; pods pubescent, not 



twisted 6. D. aureola. 



Flowering stems naked or few-leaved, arising from a densely leafy cushion; leaf- 

 blades broadly spatulate or oblanccolate. 

 Leaves ciliate, surface hairs simple or forked ; branches of root-cro^vn densely 

 leafy; pod pubescent or glabrous, undulate or twisted..?. D. lemmonii. 

 Leaves stellate-pubescent, not ciliate ; branches of root-crown leafy only at tip ; 



pods glabrous, not twisted 8. D. nivalis. 



Flowers white; leaf -blades oblong, canescent; pods pubescent; stigma subsessile 



9. D. breweri. 

 Style 1 to 2 lines long. 



Flowering stems mostly with reduced leaves, commonly much branched; corolla pale 



yellow, about 1 line long 10. D. corrugata. 



Flowering stems naked, simple; corolla deep yellow, 2 to 4 lines long 11. D. Jiowellii. 



Leaves carinate by the prominent midnerve, becoming rigid, witli reflexed margin; alpine or sub- 

 alpine cushion plants. 

 Eacemes produced beyond the leaves; corolla yellowish, fading white; pods mostly flattened; 



var. of 12. D. oUgosperma. 



Eacemes mostly hidden by the leaves; corolla white; pods about as thick as broad 



13. Z>. douglasii. 



1. D. unilateralis Jones. Stem short, parting into 2 or 3 racemes; racemes 

 lax, diffuse, or horizontal and trailing, in age rigid and wiry, 6 to 18 inches long; 

 leaf -blades cuneate-obovate to oblanccolate, 4 to 12 lines long, few-toothed or 

 entire, sessile; flowers 1 line long, on pedicels % as long; pods round-oval, 1 to 2^ 

 lines long, hispidulous, twisted when mature, tardily dehiscent, the pedicels thick, 

 recurved, ^/o to 1 line long. 



Hillsides and valleys, 100 to 800 feet : inner Coast Range from Fresno Co. to 

 Colusa Co. ; Tehachapi Mts. South to Lower California, north to Oregon. Apr. 



Tax. note. — This is a peculiar species whose phylogeny is not as yet well understood. It is 

 the monotype of Greene's proposed genus Heterodraba. The pods are often distant 1 inch or 

 more. The seeds are mostly 8 to 11. 



Locs. — Tehachapi Mts. (n. slope), ace. Peirson. Coast Eanges: Zapato Chino, sw. Fresno 

 Co., T. Brandegee ; upper San Benito Eiver, near James Creek, E. Crum 995; Livermore, Bioletti; 

 Byron, Contra Costa Co., Bioletti; Lake Co., K. Brandegee; Sites, Colusa Co., T. Brandegee. 

 Ashland, Oi'e., Howell. 



Eefs.— Draba unilateralis Jones, Bull. Torr. Club 9:124 (1882), type loc. All Saints Bay, 

 L. Cal., Jones. Heterodraha unilateralis Greene, Bull. Cal. Acad. 1:72 (1885). Athysanus 

 unilateralis Jepson, Fl. W. Mid. Cal. 224 (1901), ed. 2, 190 (1911), Man. 446 (1925). 



