344 BRASSICACEAE 



12. C. nivalis (Greene) Rydb. Cespitose perennial; stems 1-2 dm. high, 

 very leafy; leaves narrowly oblanceolate to linear, 3-5 cm. long, sparingly pubes- 

 cent; petals bright yellow, about 15 mm. long; pedicels about 5 mm. long, ascend- 

 ing; pods erect, 3-5 cm. long. Cheiranthus nivalis Greene. Summits: Colo. 

 Mont . -A lp . Jl- An . 



13. C. radicata Rydb. Perennial, branched at the base; stems 1.5 dm. or 

 less high; leaves linear-oblanceolate, sinuately toothed, 4-7 cm. long; petals 

 light yellow, about 15 mm. long; fruiting pedicels ascending; pods ascending, 

 tetragonal, about 4 cm. long. E. radicatum Rydb. High mountains: Colo. 

 Subalp. Alp. Jl. 



14. C. Wheeleri (S. Wats.) Rydb. A tall strigose biennial or perennial; 

 stem strict, simple, 3-6 dm. high, striate; basal leaves 2-7 mm. wide, subentire 

 or sinuately denticulate, grayish strigose; stem leaves mostly narrowly linear, 

 the upper sessile; pedicels short, ascending; petals with slender claws, about 15 

 mm. long, varying from orange or brown to. rose-purple; pods four-angled, 

 slender, erect, 7-8 cm. long and 1.5 mm. in diameter; beak about 2 mm. long, 

 stout. E. Wheeleri Rothr. E. alpestre Rydb., in part. Mountains: Colo. 

 N.M. Ariz. Utah. Submont. Subalp. My-Jl. 



15. C. amoena (Greene) Rydb. Cespitose perennial; stem 1-3 dm. high; 

 leaves linear-oblanceolate, 4-6 cm. long, more or less sinuate-dentate; petals 

 15-18 mm. long, brown, purple, or rose, with whitish claws; pedicels ascending; 

 pods erect, 3-5 cm. long. Cheiranthus nivalis amoenus Greene. Erysimum 

 asperum alpestre Cockerell. E. Cockerellianum Daniels. High mountains: 

 Colo. Mont. Alp. Je-Jl. 



16. C. Pallasii (Pursh) Rydb. Dwarf biennial; stem 2-10 cm. high, densely 

 leafy; leaves linear-oblanceolate or linear, 1-2 cm. long, sinuate-dentate; sepals 

 scarious-margined ; petals deep purple, 10-16 mm. long; pedicels ascending; pods 

 ascending, 4-5 cm. long, 2 mm. thick. Cheiranthus Pallasii Pursh. Arctic 

 regions: Greenl. Alta. Alaska. Alp. Subalp. Je-Jl. 



25. HESPERIS (Tourn.) L. DAME'S ROCKET, DAME'S VIOLET. 



Perennial or biennial herbs, with forked hairs. Leaves simple, dentate. 

 Flowers large, racemose, perfect. Sepals equal, not saccate at base. Petals 

 purple or white, with long claws and broad blades. Pod elongate, nearly cylin- 

 dric; valves keeled and 1-nerved. Stigma with 2 erect lobes. Seeds in a single 

 row in each cell, globose, wingless. Cotyledons incumbent. 



1. H. matronalis L. Stem erect, simple; branched above, 3-10 dm. high; 

 leaves 5-20 cm. long, ovate or ovate-lanceolate, dentate, pubescent on both 

 sides; petals purple, pink, or white; pod 5-10 cm. long, ascending or spreading, 

 somewhat torulose when ripe. Fields and roadsides: N.S. Pa. la. Mont.; 

 escaped from cultivation; native of Eurasia. My-Au. 



27. CAMPE Dulac. WINTER CRESS, SCURVY GRASS. 



Biennial or perennial herbs with angled stem, and alternate lyrate-pinnatifid 

 leaves. Flowers perfect in racemes or panicles. Sepals erect, the outer two 

 slightly saccate at the base. Petals yellow, spatulate, clawed. Pod elongate, 

 linear, somewhat 4-angled, style short; stigma more or less 2-lobed. Seeds in 

 one row in each cell, flattish, marginless. Cotyledons accumbent. [Barbarea 

 R. Br., not Scop.] 



Pod obtusely angled; leaves with 1-4 pairs of divisions. 



Divisions of the basal leaves 1-2 small pairs; pod slender, ascending. 



1. C. americana. 

 Divisions of the basal leaves 3-4 pairs; pod stouter, erect and appressed. 



2. C. stricta. 

 Pod sharply 4-angled; leaves with 4-8 pairs of divisions. 3. C. verna. 



1. C. americana (Rydb.) Cockerell. Biennial; stem 3-5 dm. high, glabrous, 

 strict; divisions of the basal leaves broadly elliptic; stem-leaves with the petioles 

 auriculate-clasping; petals 2-4 mm. long, light yellow; pod 2-2.5 cm. long, 



