32 CRUC1FERJE. 



feet high. Flowers yellow, very small, terminating the raceme which becomes 1 to 

 2 feet long, environed by the appreseed sessile pods. 



2. S. Thalianum, Hook. Mouse-ear Hedge Mustard. 



Radical leaves obovate or oblong, entire or barely toothed ; stem leaves lanceolate, 

 sessile ; pods ascending, rather longer than the pedicels. 



Hocks and sandy fields. April and May. Stem 6 to 15 inches high, Blender, 

 terete, with slender erect branches. Leaves mostly in a radical cluster, 1 to 2 inches 

 long ; those of the stem y^iol inch long, denticulate, ciliate. F lexers email, white. 

 Probably introduced. 



3. S. canescens, Nutt. Hoary Hedge Mustard. 



Leaves 2-pinnatifid, the divisions small and toothed ; petals scarcely exceeding tho 

 ealyx ; pods in long racemes, oblong or rather clavate, not longer than the spreading 

 pedicels. 



Ranks of streams. Rather rare. May. Stem slender, 1 to 2 feet high. Flower* 

 very small, pale yellow. Fedi'-els spreading with the pod, often erect. A very 

 variable species, often hoary pubescent. 



18. ERYSIMUM. Linn. Treacle Mustard. 



Gr. eruo, to draw blisters. 



Calyx erect, closed. Pods columnar, 4-sicled; stigma 

 capitate. Seeds in a single row in each cell, oblong, mar- 

 ginless; cotyledons often obliquely incumbent. — Chiefly 

 biennials with yellow flowers. 



1. E. cherianthoides, L. Wormseed Mustard. 



Leaves lanceolate, somewhat toothed, minutely roughish ; pods erect, spreading, 

 twice as long as the pedicels; stigma small, nearly sessile. 



Along streams : rare. Introduced. July — Sept. Stem 1 to 2 feet high, erect, 

 branched, roughish. Floioers yellow, in long terminal racemes. F«d about 1 inch 

 long, pointed with a short style. 



2. E. ArkansANUM, Nutt. Western Wallflower. 



Minuteby rourhish hairy ; stem simple; leaves lanceolate, somewhat toothed; 

 lower ones runcinate-toothed; flffafers racemose corymbed at summit. 



A fine plant with showy flowers resembling the Wall-flower. Native of the 

 Western States, cultivated in gardens. June and July. Biennial. £teml to 3 

 feet high, slender. Leavcs2 to 3 inches long, J/£ to Yi ' ,lf - wide. SfpaU straw-color. 

 Fetals large bright orange-yellow. Siliques 3 inches long, 4-angled. sub-erect. 



19. SINAPIS.. Linn. Mustard. 



Gr. sinapi. which is said to come from the Celtic nap, a turnip. 



Sepals equal at the base, spreading. Petals ovate, with 

 straight claws. Pods nearly terete, with a short beak ; 

 valves bearing nerves. Seeds globose, 1-rowed. — Annual 

 or hiennial European plants, with yellow flowers, and lyrate, 

 pinnatifld, or incised leaves. 



1. S. nigra, L. Blade Mustard. 



Lower leaves lyrate or lobed ; upper linear-lanceolate, entire, smooth ; pods smooth 

 and even, somewhat 4-sided, appressed to the stem, tipped with a slender style. 



