336 BRASSICACEAE 



yellow, about, 2.5 mm. long, spatulate; pedicels in fruit spreading; pod 7-10 

 mm. long, 2 mm. thick; style 0.5-0.75 mm. long. Roripa pacifica Howell. Wet 

 places: Alaska -Wash. 'Utah Alta. Submont. My-Au. 



7. R. hispida (DC.) Heller. Biennial; stem stout, branched above, 3-12 dm. 

 high; leaves lyrate-pinnatifid, with lanceolate or ovate, toothed divisions; petals 

 spatulate, yellow, 2 mm. long; fruiting pedicels ascending or spreading; pod 4-6 

 mm. long, 2 mm. thick, glabrous; style about 1 mm. long. N. hispidum DC. 

 Water and wet places: N.B. Fla. N.M. Wash. Utah Alaska. Plain 

 Submont. Je-Au. 



8. R. terrestris (R. Br.) Woot. & Standl. Annual or biennial; stem branched 

 above, 3-10 dm. high; leaves lyrate-pinnatifid, with oblong or lanceolate, toothed 

 divisions; petals yellow, spatulate, 2 mm. long; fruiting pedicels usually spreading; 

 pod 5-7 mm. long, 2 mm. thick; style 1 mm. long. Sisymbrium amphibium 

 palustre L. N. terrestre R. Br. N. palustre DC. Radicula palustris (L.) Moench. 

 Water and wet places: Lab. -Ga. N.M. Alaska; Eurasia, Mex. Plain 

 Submont. Ap-O. 



9. R. alpina (S. Wats.) Greene. Biennial; stem branched below, 1-3 dm. 

 high; leaves sinuately lobed, rarely pinnatifid, elliptic or oblanceolate, obtuse; 

 petals spatulate, 2.5 mm. long; pedicels spreading; pod about 5 mm. long, 2 mm. 

 thick; beak about 0.5 mm. long. N. obtusum alpinum S. Wats. Wet places in 

 the mountains: Mont. Colo. Utah -Ida. Submont. Subalp. Jl-Au. 



10. R. sphaerocarpa (A. Gray) Greene. Annual or biennial; stem diffusely 

 branched from the base, 1-3 dm. high, glabrous; leaves sinuately or lyrately 

 lobed, with rounded lobes; petals yellow, 1.5 mm. long; pedicels 2-3, rarely 5 mm. 

 long; pod 2-3 mm. long, nearly 2 mm. thick; style about 0.5 mm. long. .V. 

 sphaerocarpum A. Gray. Along streams: 111. -Tex. Calif. Wyo. Plain 

 Submont. Jl-S. 



11. R. obtusa (Nutt.) Greene. Annual; stem diffusely branched at the 

 base, 1-3 dm. high, glabrous; leaves pinnatifid, with obovate or rounded, sinu- 

 ately toothed divisions; petals narrowly spatulate, 1 mm. long; pedicels ascend- 

 ing or spreading; pod 4-8 mm. long, 1-2 mm. thick; style about 1 mm. long. 

 N. obtusum Nutt. Wet places: Mich. Mo. Tex. Utah Wash. Plain 

 Submont. Je-S. 



12. R. curyipes Greene. Annual; stems 1-3 dm. high, diffusely branched; 

 leaves lyrate-pinnatifid or lobed, usually with acute divisions; petals about 1 

 mm. long; pedicels spreading or recurved; pod about 5 mm. long, somewhat 

 curved, about 2 mm. thick, acute at the apex. Roripa curvipes Greene. Wet 

 places in the mountains: Utah Wyo. N.M. Submont. Subalp. Jl-S. 



13. R. curvisiliqua (Hook.) Greene. Annual or biennial; stem diffusely 

 branched, 1-3 dm. high, glabrous; leaves pinnately divided, with many oblong, 

 mostly obtuse divisions, glabrous; petals yellow, 2.5 mm. long, oblanceolate; 

 pedicels 4-5 mm. long; pod curved, 8-12 mm. long, about 1 mm. thick. Sisym- 

 brium curvisiliquum Hook. N. curvisiliquum Nutt., in part. Wet places: Mont. 

 Wyo. Ore. Wash. My-S. 



14. R. Nuttallii (S. Wats.) Greene. Biennial; stems solitary or several, 

 erect, rather simple, 3-4 dm. high, glabrous; leaves pinnately lobed or toothed, 

 with lanceolate or triangular lobes or teeth, or the lower ones with linear divis- 

 ions; petals 2-2.5 mm. long, oblanceolate; pedicels 2-4 mm. long; pod' 8-15 mm. 

 long, 1 mm. thick, somewhat curved. N. curvisiliqua Nuttallii S. Wats. N. 

 Nuttallii Rydb. Wet places: Wash Calif. (? Mont.) 



15. R. lyrata (Nutt.) Greene. Annual; stems diffusely branched, 1-3 dm. 

 high, glabrous; leaves pinnately divided, with oblong to ovate, coarsely toothed 

 divisions; petals scarcely 1 mm. long; pedicels 1-3 mm. long, ascending; pod 

 6-15 mm. long, 1-1.5 mm. thick. N. lyratum Nutt. Wet places: Mont. Colo. 

 Calif. Wash. Plain Submont. Jl-Au. 



16. R. Underwoodii (Rydb.) Heller. Biennial; stem 2 dm. or more high, 

 divaricately branched, perfectly glabrous; leaves 3-5 cm. long, lyrately pinna- 

 tifid, thin; lobes oblong, obtuse, the terminal one elliptic to broadly oval, sinu- 



