340 BRASSICACEAE 



5-8 mm. long, 0.75 mm. thick, linear, nearly cj-lindrical, tapering somewhat 

 at both ends, slightly tonilo.se. Mountains: Colo. Submont. S. 



9. S. ramosa Rydb. Stems 3-6 dm. high, finely but sparingly stellate; 

 leaves once or twice pinnate; divisions linear or linear-oblong; petals oblanceolate, 

 pale yellow, slightly longer than the sepals; pod somewhat clavate, 8-10 mm. 

 long, erect or strongly ascending, about 1 mm. thick. Mountains: Colo. Mont. 

 S. 



10. S. filipes (A. Gray) Heller. Stem branched, 3-6 dm. high, ahnost 

 glabrous; leaves once to twice pinnatifid, sparingly stellate or glabrous; segments 

 linear or oblong, often lobed; petals bright yellow, 3 mm. long or more; pedicels 

 1-2 cm. long; pods clavate, erect, 12-15 mm. long, 1.5-2 mm. thick. Moun- 

 tains, canons, and plains : Sask. — N.D. — Colo. — Utah — Wash. — B.C. Submont. 

 Ap-Jl. 



11. S. magna Rydb. Stem branched, 5-10 dm. high, sparingly stellate- 

 puberulent or glabrous, stout; basal leaves twice to thrice pinnatifid, 1-2 dm. 

 long, nearly glabrous; segments obovate, often toothed; petals spatulate, nearly 

 3 mm. long, rather light yellow; pod glabrous, more or less clavate, 12-15 mm. 

 long, 1.5-2 mm. thick. River bluffs: Colo. Mont. 



12. S. intermedia Rj-db. Stem 3-7 dm. high, often glandular above; 

 leaves twice or thrice pinnatifid; segments hnear or linear-oblong; petals spatu- 

 late, slight^ if at all exceeding the sepals; pedicels in fruit 1-1.5 cm. long, usually 

 spreading; pods clavate, glabrous, 8-12 mm. long, 1.5 mm. thick, near!}' erect. 

 Prairies, plains, and waste places: Mich. — Tenn. — Colo. — Calif. — B.C. Plain — • 

 Mont. My-Jl. 



13. S. andrenarum CockereU. Stem 3-7 dm. high; lower leaves twice 

 pinnatifid, with small oblong or ovate divisions, the upper more simple and 

 with linear elongated divisions; petals spatulate; pod ascending or erect, clavate, 

 about 1 cm. long, 1.5 mm. thick. Dry ground: Mont. — N.M. — Ariz. — -Wash. 

 Plain — Mont. My-Jl. 



14. S. halictorum CockereU. Stem branching, 3-5 dm. high; leaves twice 

 pinnate, with short linear or oblong divisions; pedicels 5-10 mm. long; pods 

 clavate, nearly 1 cm. long, erect or nearly so. Dry regions: Tex. — -Colo. — Utah 

 — Ariz. Son.- — Submont. Ja-Je. 



15. S. pinnata (Walt.) HoweU. Stem 3-6 dm. high; leaves thrice or twice 

 pinnatifid into short, obovate, oval, or elliptic divisions; petals pale j-eUow; 

 pedicels spreading, 7-12 mm. long; pod clavate, 5-8 mm. long. Sisymbrium 

 canescens Nutt. Sandy or dry soil: Va. — Fla. — Ariz. — Colo. Plain. ^Ir-Je. 



16. S. Nelsonii Rydb. Stems 2-A dm. high; leaves pinnatifid or bipinnatifid, 

 with linear or oblong divisions; petals light yellow, spatulate, 1.5 mm. long; 

 fruiting pedicels ascending, 4-6 mm. long; pods clavate, 5-8 mm. long, glabrous, 

 slightly over 1 mm. thick. Gravelly flats, sandy plains, &c.: Wyo. — Utah. 

 Plain — Submont. 



17. S. leptostylis Rydb. Stem 3-6 dm. high, rather simple below, spar- 

 ingly stellate or glabrous; leaves 3-10 cm. long, twice pinnatifid into oblong 

 divisions; petals spatulate, slightly surpassing the sepals; pedicels in fruit 5-8 

 mm. long; pod about 5 mm. long, tapering at both ends; style 0.5-0.7 mm. long. 

 Mountain vallej-s: U+ah. Mont. Je-Au. 



18. S. procera Greene. Stem 5-20 dm. high, simple below; leaves twice 

 pinnatifid, with lanceolate, toothed segments, or the lower ones with obovate 

 segments; petals spatulate, about 2 mm. long; pedicels 5-8 mm. long; pods 6-10 

 mm. long, over 1 mm. thick, tapering at both ends; style nearly 0.5 mm. long. 

 Sandy valleys and hills: Colo. — Utah — Wyo. Submont. — Mont. Jl-S. 



19. S. Hartvegiana (Fourn.) Greene. Stem 6-20 dm. high; leaves twice 

 pinnatifid, with lanceolate divisions; petals spatulate, light yellow, 2.5-3 mm. 

 long; pedicels 5-8 mm. long; pod linear, 10-15 mm. long, 1 mm. thick. S. 

 brevipes (Nutt.) Rydb. River banks, waste grounds, and sandy valleys: Sask. 

 — Minn. — Colo. — Utah — B.C. Plain — Submont. Jl-Au. 



