MUSTARD FAMILY ^ 335 



Annuals or biennials. 



Pods tliickened towards the apex and truncate, curved, longer than the pedicels. 



Pods not thickened towards the apex, acute or obtuse. 



Pods spherical to oblong-ellipsoid, in the latter case shorter than the pedicels 

 Pedicels 4-10 mm. long. 



Pods 5-8 mm. long, 2-3 mm. thick; stem sparingly hirsute. 



•n J « ^ , . , Q. R. pacifica. 



Pods 3-5 mm. long (rarely 6-7 mm. in R. palustris), 1.5-2 mm. thick. 



Stem more or less hirsute. 7. R. hispida 



Stem glabrous. 



Stem tall, 3-8 dm. high; stigma prominent, 2-lobed. 



8. R. terrcslris. 

 Stem low, divaricately branched, 1-3 dm. high; stigma scarcely 

 X. ^. , « thicker than the style. 9, R, alpina. 



Pedicels 2-5 mm. lon^. pod globose. 10. R, sphaerocarpa. 



Pods oblong to hnear-cyhndrical, equalling or longer than the sliort pedicels. 

 Style about 1 mm. long. 



Leaves nearly all pinnatifld, with obtuse divisions. 11. R. obtusa. 

 Leaves mostly sinuate, or if pinnatifld, with acute divisions. 



Pods short-ellipsoid, straight on straiglit pedicels. 10. R. sphaerocarpa. 

 Pods elongate-ovoid, curved, on curved pedicels, 12. R. curvipes. 

 Style minute, 0.5 mm. long or less. 



Pods 1.5 mm. thick or less, distinctly pedicelled; seeds tuberculate. 



Petals about 2 mm. long or more; pods linear, 1 mm. or less thick, 



strongly curved. 

 Leaves divided to near the midrib, their segments obtuse. 



13. R. curvisiliqua. 

 Leaves merely cleft, with acute segments. 14. R, NuUallii. 



Petals rarely more than 1 mm. long; pods usually slightly tapering 



upwards, about 1.5 mm. tliick, straight or slightly curved. 

 Leaves pmnatifid. 



Low, slender, less than 2 dm. high ; leaves not auricled at the base. 



15. R. lyrata. 

 Taller and stouter, over 2 dm. high; petioles of the stem-leaves 

 auricled at the base. 16. R. Underwoodii. 



Leaves entire or merely sinuate. - 17. R. Integra. 



Pods fully 2 mm. thick, almost sessile; seeds pitted. IS. R. sessiliflora, 



!• R. calycina (Engelm.) Greene. Stem hirsute, erect, 2-3 dm. high; leaves 

 oblong or oblanceolate, sessile and even subclasping, coarsely toothed; racemes 

 rather dense; pedicels ascending, 5-8 mm. long; petals light yellow, shghtly 

 exceeding the sepals; pod erect, ovate, 3-5 mm. long; st3'le more than half as 

 long. Nasturtium calycinum Engelm. Sandy bottoms: Mont. Plain, Jl. 



2. R. trachycarpa (A. Gray) Rydb. Stem branching, papillose-puberulent 

 or glabrous; leaves lyrate-pinnatifid, with many oblong divisions, nearly gla- 

 brous; petals white, 5 mm. long; pedicels spreading; pod oblong-linear, curved, 



ascending. A^. trachycarpum A. Gray. Wet places: s Colo. Plain — Submont. 

 Je. 



- 3. R. Columtaiae (Suksd.) Greene. Stem branched, 1-3 dm. high, papil- 

 lose or glabrate; leaves pinnatifid, with many oblong often toothed divisions; 

 petals yellow, spatulate, 4 mm. long; pedicels ascending or spreading; pod ascend- 

 ^g or erect, curved, 5-8 mm. long; style nearly 2 mm. long. Roripa calycina 

 Rydb., not Nasturtium calycinum Engelm. River banks and wet sandy places: 

 Mont.— Neb.^N.M.— Wash. Plain— SubmanL Je-JL 



4« R. sinuata (Nutt.) Greene. Stems 1-4 dm. high, glabrous or nearly so; 

 leaves glabrous, pinnately divided or cleft, with numerous oblong or lanceolate, 

 often toothed divisions; petals yellow, 4-5 mm. long; pod curved upwards, gla- 

 brous, 1-1.5 cm. long, 2 mm. thick; style 3 mm. long. N. sinuaium Nutt. 

 River valleys: Sask.— Minn.— III.— Tex.— Ariz.— Wash.; Ont. Plain. Ap-Au. 



6. R, clavata (Rydb.) J. M. Macoun. Biennial, perfectly glabrous; stem 

 y-lQ dm. high, simple up to the inflorescence; leaves lyrate-pinnatifid, 5-10 cm. 

 long, more or less auricled at the base; lobes oblong to ovate, broadly dentate; 

 pedicels in fruit 5-10 mm. long, divaricate; petals spatulate, about 3 mm. long; 

 pod 10-12 mm. long, 2.5-3 mm. thick; style nearly 1 mm. long. Roripa clavata 

 -K-ydb. River valleys: Ida. — Ore. — -Alaska. Submont, Ap-S. 



6. R. pacifica (Howell) Greene. Annual or biennial; stem 3-10 dm. high, 

 glabrous, or shghtly hairy, branching above; leaves lyrately pinnatifid or pin- 

 nately lobed, with oblong-lanceolate or triangular, toothed divisions; petals 



