MUSTARD FAMILY 367 



Pods 2-3 cm. long; basal leaves oblanceolate or spatulate. 



Petals 5-6 mm. long; blades spatulate; pedicels nearly erect. 



1. T. P aimer i. 

 Petals 7-9 mm. long; blades obovate; pedicels spreading or ascending. 



2. T. sagittatum. 

 Pods 1-2 cm. long; basal leaves oval. 3. T. ovalifolium. 



Petals 10-15 mm. long, about three times as long as the sepals. 



Pods 4-5 cm. long, 1 mm. wide. 4. T. macropetalum. 



Pods about 3 cm. long, nearly 2 mm. wide. 5. T. Nuttallii. 

 Pods 5-10 cm. long, arcuate, spreading or ascending. 



Stem stout; lower leaves coarsely sinuate-dentate; petals obovate, more than 2 



mm. wide. 6. T. ambiguum. 

 Stem slender; lower leaves entire or slightly sinuate; petals narrowly spatulate, 



barely 2 mm. broad. 7. T. eucosmum. 

 Upper leaf-blades attenuate at the base; leaves mostly laciniate. 

 Petals narrowly linear-oblanceolate. 



Pods divergent; raceme lax. 8. T. leptosepalum. 



Pods erect; raceme dense. 9. T. milleflorum. 



Petals spatulate; pods reflexed; raceme lax. 10. T. utahense. 



1. T. Palmeri Rydb. Biennial, with a taproot; stem 3-5 dm. high, spar- 

 ingly hirsute below, glabrous above; basal leaves 2-4 cm. long, more or less hir- 

 sute beneath, especially on the veins; stem-leaves sagittate, 2-4 cm. long, gla- 

 brous or nearly so; inflorescence usually branched; petals white or rose; pod 

 about 2-5 cm. long, 1 mm. wide. Arid regions: s Utah. Son. 



2. T. sagittatum (Nutt.) Endl. Biennial; stem 3-6 dm. high, branched 

 above, glabrous or nearly so; basal leaves oblanceolate, 2-6 cm. long, glabrous 

 or sparingly hirsute; stem-leaves sagittate, 2-6 cm. long, glabrous; petals white 

 or purplish; pods 1 mm. wide, nearly erect, somewhat torulose. T. paniculatum 

 A. Nels. T. torulosum Heller. Sage plains and alkali soil: Mont. Colo. 

 Utah Ida. Son. Submont. Je-Au. 



3. T. ovalifolium Rydb. Biennial or perennial, perfectly glabrous; stems 

 terete, 3-5 dm. high; earliest basal leaves about 5 cm. long, petioled, with broadly 

 oval blades, the later ones oblanceolate; stem-leaves sagittate, 2 cm. long, thick; 

 petals about 5 mm. long, with spatulate blades; pedicels in fruit 4-5 mm. long, 

 spreading; pods ascending, about 1 mm. wide, somewhat torulose. Plains: 

 Utah. Son. Au-S. 



4. T. macropetalum Rydb. A glabrous perennial, 4-6 dm. high; basal 

 leaves oblanceolate or spatulate, 2-5 cm. long; lower stem-leaves oblong, obtuse, 

 sessile, 5-6 cm. long; upper leaves lanceolate-sagittate, acute; pedicels divari- 

 cate; petals purple, spatulate; pods 1 mm. wide, ascending or erect and some- 

 what incurved. Hills and plains: Utah Ida. Submont. My-Je. 



5. T. Nuttallii S. Wats. Biennial, glabrous and glaucous; stem 4-10 dm. 

 high; basal leaves 5-15 cm. long, lanceolate; stem-leaves sagittate, 2-10 cm. 

 long; petals lilac or whitish, 10-15 mm. long; pod nearly 2 mm. thick; style 1 

 mm. long. Streptanthus sagittatus Nutt. T. sagittatum Heller, not Endl. 

 Plains and valleys: Wyo. Utah Ore. 'Wash. Son. Je-Au. 



6. T. ambiguum S. Wats. Stout biennial, glabrous; stem 6-15 dm. high; 

 radical leaves thick, coarsely toothed, 1-2 dm. long, oblanceolate; stem-leaves 

 4-5 cm. long, subentire; petals purplish, about 1 cm. long; blade obovate; pod 

 2 mm. thick; style very short. Arid regions: s Utah Ariz. Son. 



1. T. eucosmum B. L. Robins. Glabrous biennial or perennial (?); lower 

 leaves oblong, entire or slightly sinuate, the upper lanceolate, clasping, 3-7 cm. 

 long; racemes several, many-flowered; pedicels 4-6 mm. long, spreading; petals 

 deep purple, 8 mm. long; pod arcuate, ascending. Mountains: Ore. Ida. 

 My-Je. 



8. T. leptosepalum Rydb. Annual or biennial, glabrous throughout; stem 

 4-6 dm. high, branched; leaves thin, glabrous, 6-10 cm. long, lyrate-pinnatifid, 

 with lanceolate divergent lobes; petals with scarcely any distinction between 

 blade and claw, 8 mm. long, 0.5 mm. wide or less. Rocky banks: Ida. Son. 



9. T. milleflorum A. Nels. Glabrous biennial, 1-2 m. high; leaves coarsely 

 and irregularly dentate to entire, oblong or lanceolate below to linear above; 

 inflorescence often 4-6 dm. long; flowers numerous, crowded; petals white, twice 



