MUSTARD FAMILY 339 



Terminal segments not greatly elongate; segments of the lower 



leaves obovate. 11. S. magna. 



Petals not much exceeding the sepals; segments narrow; terminal 



segments of the upper leaves not elongate. 12. 3. intermedia. 

 Leaves and stem cinereous-stellate. 



Petals longer than the sepals, about 2 mm. long; upper leaves mostly 

 once pinnate, with elongate, broad terminal segments. 



13. S. andrenarum. 

 Petals not longer than the sepals, about 1.5 mm. long; upper leaves 



usually more dissected; terminal segment narrow, not elongate. 



14. S. halictorum. 

 Pods 5-8 mm. long. 



Pods acute above, acuminate below; style obsolete. 



Pods ascending or spreading. 15. S. pinnata. 



Pods erect; leaves sparingly stellate. 16. S. Nelsonii. 



Pods acuminate at both ends; style evident. 17. S. leptostulis. 

 Pedicels erect. 



Pods over 1 mm. thick. 



Plant green and almost glabrous. 18. S. procera. 

 Plant cinereous-pubescent. 19. S. Hartvegiana. 

 Pods about 0.75 mm. thick; plant glandular-puberulent, especially the inflores- 

 cence, or glabrous. 20. S. glandulifera. 

 Lower leaves merely coarsely toothed or lobed; pod twisted. 21. S. perplexa. 



1. S. Sophia (L.) Britton. Stem much branched, 3-10 dm. high, minutely 

 pubescent; leaves thrice pinnate, with narrowly linear divisions; petals cream- 

 colored; pod erect, somewhat curved, glabrous, about 2 cm. long, less than 1 

 mm. thick, torulose. Sisymbrium Sophia L. Waste places: N.B. N.Y. 

 Utah Ore. Wash.; nat. from Eu. Je-Jl. 



2. S. sophioides (Fisch.) Heller. Stem 3-5 dm. high, slightly viscid-puberu- 

 lent; leaves thrice pinnate, with linear or oblong divisions, nearly glabrous; 

 petals spatulate, cream-colored; pod 2-2.5 cm. long, 1 mm. thick, filiform. Sisym- 

 brium sophioides Fisch. Subarctic regions: Hudson Bay Man. B.C. Alaska. 

 Subalp. Jl. 



3. S. gracilis Rydb. Stem slender, 1-3 dm. high, finely stellate, somewhat 

 branched; leaves 1-5 cm. long, once or twice pinnatifid, with linear or oblong 

 lobes; petals 2-2.5 mm. long, light yellow; pedicels ascending; pods 1-1.5 long, 



1 mm. thick, more or less curved. Hills and meadows: Wyo. Wash. Mack. 

 Submont. My-Jl. 



4. S. californica (T. & G.) Rydb. Stem 3-4 dm. high; leaves twice pin- 

 nate, the lower with oblong obtuse divisions, the upper with linear ones; petals 

 light yellow, 3-4 mm. long; pedicels ascending; pod filiform, 1-1.5 mm. (rarely 



2 mm.) long, 1 mm. thick, erect. Sisymbrium canescens californicum T. & G. 

 Waste places: Calif. B.C. Mont. Son. Submont. Ap-Je. 



5. S. leptophylla Rydb. Stems 5-7 dm. high, sparingly glandular; leaves 

 very thin, only once pinnate; segments of the lowest leaves rounded, those of the 

 middle lanceolate and somewhat incised, those of the upper entire; petals bright 

 yellow, about 1.5 mm. long; pod linear, 8-10 mm. long, much less than 1 mm. 

 thick, torulose, spreading, arcuate, curved up. Foot-hills: Colo. Mont. Sub- 

 mont. Mont. Jl-Au. 



6. S. incisa (Engelm.) Greene. Stem 3-10 dm. high, usually branched, 

 slightly stellate or glabrate; leaves thin, pinnate or the lower twice pinnate; 

 segments lanceolate, deeply toothed, acute; petals bright yellow, 3 mm. long;, 

 pedicels usually spreading; pod filiform, 1-1.5 cm. long, scarcely 1 mm. thick, 

 somewhat curved. Sisymbrium incisum Engelm. Hills and canons: N.M. 

 Wyo. Utah. Submont. Mont. My-Jl. 



7. S. viscosa Rydb. Stem 5-10 dm. high, at least the upper part decidedly 

 glandular or viscid-villous; leaves 3-10 cm. long, twice pinnatifid, densely pubes- 

 cent; primary divisions of the lower leaves ovate and obtuse, those of the upper 

 lanceolate and acute; secondary divisions oblong, acute or obtuse; petals bright 

 yellow, spatulate, 2-3 mm. long; pod over 1 cm. long and less than 1 mm. thick. 

 Canons and grassy slopes: Wyo. Nev. B.C. Son. Je-Au. 



8. S. purpurascens Rydb. Stem very slender, diffusely branched above, 

 glabrous and purplish; upper leaves simply pinnate, with linear-oblong divisions, 

 slightly stellate; pedicels ascending in fruit, 4-5 mm. long; fruit very slender, 



