486 CRUCiFKRAi-: (mustard family^ 



leaflets ; stem-leaves on sarjittntdii appendaf/ed petioles ; terminal leaflet mostly 

 3-lobed ; pods 2.5-3 cm. long, much exceeding the pedicels. — Springy places in 

 the mts., s. Va. and southw. 



* * * Fibrous-rooted alpine perennial with simple leaves ; northern. 



5. C. bellidifolia L. Dvmrf (2-3.5 cm. high), densely tufted; leaves ovate, 

 entire, or sometimes with a blunt lateral tooth, 2-10 mm. long, slender-petioled ; 

 riowers 1-5, white; pods 1.5-2 cm. long, upright, linear; style extremely short, 

 stout. — Arctic regions and alpine districts of the n. hemisphere. Represented 

 with us by 



Var. laxa Lange. Looser and taller (4-11 cm. high) ; leaves 6-15 mm. long, 

 on very long petioles ; pods 2-3 cm. long. — By alpine brooks, and in cold 

 ravines, Lab. to ]Mt. Katahdin, Me., and Mt. Washington, N. H. ; by a brook, 

 W. Baldwin, Me. {Miss Furbish). June, July. (Greenl.) 



* * * * Boot perennial ; leaves pinnate ; flowers showy. 



6. C. pratensis L. (Ccckoo Flower.) Stem ascending from a short root- 

 stock, simple ; leaflets numerous, tho.se of the lower leaves rounded and stalked, 

 of the upper oblong or linear, entire, or slightly angle-toothed ; petals (white 

 or rose-color) thrice the length of the calyx ; pod 2-3 cm. long, 2 mm. broad ; 

 style short. — Wet places and bogs, Lab. to Vt., N. J., Minn., and northw. ; 

 rare. May. Also introduced or a local escape in e. and s. N. E. (Fu.) 



* * * * * j^ooi mostly biennial or annual; leaves pinnately 6-11-foliolate ; 



flowers small, white. 



1- Stamens 4; leaflets strigose-hispid upon the upper surface. 



7. C. hirsiita L. Leaves chiefly radical, with short and broad leaflets, but 

 those on the erect stem reduced and with narrow leaflets ; pods erect, on 

 ascending or appressed pedicels. — Moist places, s. Pa. to N. C, and "Mich." 

 (Eu.) Perhaps introduced. A doubtful specimen from w. Mass. {Miss Vail). 



•t- -t- Stamens normally 6; leaflets glabrous; stem leafy. 



8. Cc parviflbra L. Very slender, subsimple, glabrous or slightly pubescent 

 upon the stem ; leaflets of the radical leaves oval or the terminal suborbicular ; 

 those of the cauline very narrow, linear, not confluent; pods erect, on ascending 

 pedicels. (C hirsuta, var. sylvatica of some Am. auth.) — Rocky and barren 

 soil, Me. to Ga. and westw. (Fu.) A form more branched from the base and 

 with leaflets all narrow and often toothed has been described as C. arenicola 

 Britton, growing in sandy soil in the Atlantic States but lacking constant 

 characters. 



9. C. pennsylvanica Muhl. Larger, nearly or quite glabrous ; leaflets 7-11, 

 the terminal one obovate, the lateral oblong, tending to be confluent along the 

 rhachis ; pods erect, on ascending pedicels. (C. hirsuta Man. ed. 6, in gi'eat 

 part.) — Moist ground, common. Passes impercepti])]y into a form (C flexuosa 

 Britton, perhaps Withering) with fewer more flabelliform leaflets and spreading 

 pods. — Brooks, etc. 



31. ARABIS L. Rock Cress 



Pod linear, flattened ; placentae not thickened ; the valves plane or convex, 

 more or less 1-nerved in the middle, or longitudinally veiny. Seeds margin- 

 less or winged. Cotyledons accumbent or a little oblique. — Leaves seldom 

 divided. Flowers white or purple (rarely yellowish). (Name from the 

 country, Arabia.) 



§ 1. SISYMBRINA Wats. Seeds oblong or elliptical, very small, wingless, in 

 one row ; cotyledons often more or less oblique ; biennial or perennial, 

 branching from base. 



1. A. lyrata L. Mostly glabrous, excei)t the lyrate-pinnatifld root-leaves; 

 Stem-leaves .scattered, spatulate or linear with a tapering base, sparingly toothed 



