342 BRASSICACEAE 



V 



coarsely toothed; petals clawed, spatulate, 4 mm. long; pods erect, stellate, 2-3 

 cm. long, about 1 mm. wide, torulose; style about 0.5 mm, long. Sisymbrium 

 humile Hook., not Meyer. Pilosella Richardsonii Rydb. Sandy plains: Mack. 

 — Alta.— (? Ore.)— B.C.— Alaska. Boreal— Mont J^Jl. 



3. A. virgata (Nutt.) Rydb. Stem 2-4 dm. high, simple or branched; 

 hu-sute with branched hairs; basal leaves 2-5 cm. long, oblanceolate, spatulate, 

 or oblong, stellate and somewhat hirsute; petals about 4 mm. long, spatulate; 

 pod erect, 2-3 cm. long, nearly 2 mm. wide, style obsolete. Sisymbrium vir- 

 gaium Nutt. Arabis Brebneriana A. Nels. Plains and hills: Wyo.— Colo. 

 Plain — Submoni. Je. 



4. A. stenocarpa Rydb. Stem hirsute with branched hairs; basal leaves 

 oblanceolate, 2-3 cm. long, sinuate-dentate, short-petioled, hirsute-stellate; 

 petals spatulate, 3 mm, long; pod 2.5-4 cm. long, glabrous, scarcely 1 mm. wide. 

 Pilosella slenocarpa Rydb. Dry plains: Sask.— Colo.— Wyo. Plain, Je--Jl. 



6. A. glauca (Nutt.) Rydb. Stem 2-3 dm. high, glabrous; basal leaves 



spatulate, entire; stem leaves lanceolate, sagittate at the base; petals spatulate, 



2 mm. long; pod erect, about 1.5 cm. long, nearly 1 mm. wide, glabrous; style 



obsolete. Sisymbrium glaucum Nutt. Prairies: Colo.— Ida.— Alta. Plain— 

 SubmonL 



25. CHEIRINIA Link. Wild Wall-flower, Praihie-rocket, 



Yellow Phlox. 



_ Annual, biennial, or perennial leaf^^-stemmed herbs, with appressed 2-branched 

 hairs (the hairs appearing as if attached near the middle). Flowers perfect in 

 terminal racemes, usually rather large. Sepals erect, the outer two gibbous at 

 the base. Petals yellow, brown, or purple, clawed, with spreading blades, 

 -bilaments free, unappendaged. Pods elongate-hnear, more or less 4-angled, or 

 at least with a strong midrib. Style short; stigma 2-lobed. Seeds in one row 

 in each pell, numerous, marginless or margined at the apex. Cotyledons in 

 ©ur species incumbent or nearly so. [Erysimum L., in part.] 



Petals less than 1 cm. long. 

 Petals 4-5 mm. long. 

 Petals 6-10 mm. long. 



Perenmals or biennials; pods ascending. 2 C inconspicua. 



T>«f .Annuals; pods spreading. - 3] C. repanda. 



Petals more than 1 cm. long o. ■ y 



Petals light yellow. 



Biennials or short-lived perennials, not cespitose 



i'ocls almost terete, slightly compressed, tapering into a style more than 2 mm. 



long. A {J nridQ, 



Pods 4-angled: style only slightly narrower, very short. 



nasal leaves, as well as whole plant, graj-ish-strigose. not silvery. 



-Pods widely spreading. 4-8 cm. long, stout; stem-leaves usually sinuate- 

 dentate. 5. c. aspera, . ^ 



f'oas strongly ascending or almost erect, 8-12 cm. long (except in ^^ 



orachycarpa) . 

 Stem-leaves usually sinuately dentate. 6. C. elata. 



btem-leaves entire or rarely denticulate. 



Stem-leaves linear or nearly so; pod usually twisted, slender. 



7. C. asperrima. 



1. C. cheiranthoides 



Stem-leaves oblanceolate; pod straight, stout 

 Pod about 8 cm, long, 1.5 ram. thick. i 



8. C. oblanceolata 



Tioo<.i 1 \. . "^"^ ^"^- ^^"g' 2.5 mm. thick. 9. C. brachycarpa 



uasai leaves at least, silvery white; stem-leaves narrowly linear, 

 i-iant 2-3 dm. lugh; stem-leaves sinuate-dentate. 

 ■Di * , « J , . 10. C. Baken. 



Low cespitole^'per^nnl^s.'^'^'^^ stem-leaves entire. 11. C. argiUosa, 



T^on^f entire-margiaed or minutely denticulate. 12. C. nivalis. 



Leaves sinuate-dentate. "^ ^' W c radicata. 



Petals varying from orange to brown or purple ' 



i^lant simple. 3-5 dm. high; basal leaves 5-10 cm. long, oblanceolate. 

 T>i 4- .. 14 C Wheelen. 



dm 



:nni 



^^^^.^^ ^«u»^cA, ai,exii usually more cnan x uiu. uib"- 



^'^IVi^^lf*®'" ^ ^'^^^'^ ^ ^^^ ^ni- ^gb» inore elongate inVuit.^Cafy.o^ly at 

 tne Dase. =* ir r? Pallasit, 



