232 ORDER 13. CRUCIFERJ3. 



Siliques when mature 1 J 2' long, 1" wide, tipped with a short style. Cotyledons 

 obliqueiy 0= or nearly 0||. Apr., May. 



0. A variety (A. PETR./EA Lam. ?) has very slender, upright stems, smooth, a 

 few small, incised root-lvs., few linear stem-lvs. and cotyledons wholly 0=. 

 Shores of the great lakes (Ohio), Can. 



3 A. Thaliana L. MOUSE-EAR CRESS. Sts. branched at base, erect; Ivs. pilous, 

 oblong, nearly entire ; petals twice longer than calyx; pods erect, squarish. @ Rocks 

 and sandy fields, Vt. to 111. and Car. "Whole plant pubescent with stellate-hairs. 

 St. several from ihe same root, erect, simple, slender, 4 12' high. Root-lvs. 

 rosulate, petiolato, 12' long, cauline oppressed, an inch long, base somewhat 

 clasping. Pis. small, white. Pods 6 8" long. Cotyledons obliquely Oj. May. 

 Kar. (Sisymbrium, Gay.) 



4 A. dentata Torr. & Gr. Sts. branched at base, diffuse ; Ivs. roughish-downy, 

 oblong, sharply toothed; petals hardly longer than calyx; pods spreading. CD 

 River banks, N. Y. to Mo. Plant scabrous with stellate hairs. Sts. decumbent, 

 a foot high. Root-lvs. 2' Jong by f ; cauline half-clasping with an auriculato 

 base, all very obtuse and irregularly toothed. Pis. small, whitish. Pods very 

 slender, 1' long. May. 



5 A. patens Sullivant. Erect, pubescent; cauline Ivs. coarsely toothed ; siliques 

 spreading and curved upwards, beaked with a distinct style. Rocky banks of tho 

 Scioto, 0. (Sullivant), and southward. Sts. 1 2f high. Root-lvs. rosulate, petio- 

 late ; stom-lvs. oblong-ovate or linear, auriculate-clasping. Pis. rather large (5 6" 

 broad), white. Pods nearly 2' long. May. 



6 A. hirsuta Scop. Erect, hirsute ; radical Ivs. oblong-ovate, tapering to a pe- 

 tiole, cauline oval or lanceolate, sagittate-clasping, entire or toothed ; siliques 

 straight, erect ; sty. none. (1) Pound in low, rocky grounds, Can. to Va., W. to 

 Oregon. Sts. 2 or more from the same root, round, hairy at base, near a foot 

 high, slender and parallel. Lvs. scarcely dentate, sessile, with heart-shaped or 

 arrow-shaped bases, the upper acute. Pis. greenish-white. Siliques 1 2' long. Jn. 



7 A. laevigata DC. Tall, glaucous, smooth; stem-lvs. linear-lanceolate, and 

 linear, sagittate-clasping, the upper entire ; siliques very long, linear r at length 

 spreading and pendulous. ^ In rocky woods and low grounds, Can. to Tenn. 

 and westward. St. 2f high, round, simple, or branched above. Root-lvs. often 

 purplish, obovato and oblong, petiolate, | !' long, as wide, with acute teeth. 

 Stem-lvs. 3 5' long and very narrow. Pis. erect, greenish, the petals hardly 

 longer than the calyx. Siliques 3' long, scarcely 1" wide. May. 



8 A. Canadensis L. SICKLE POD. Tall, pubescent; stem Ivs. lanceolate, pointed 

 both ways, sessile ; silique subfalcate, veined, pendulous. ^J. On rocky hills Can. 

 to Ga., W. to Ark. A plant remarkable for its long, drooping pods which resem- 

 ble a sickle-blade, or rather a scythe. St. 2 3f high, slender, round, smooth, 

 Lvs. 3 5' long, \ as wide, the lowest early marescent, middle and upper ones 

 sessile or clasping, with narrow bases, remotely denticulate. Pis. small, the nar- 

 row, white petals twice longer than the calyx. Pods slender, flattened, 3' long. 

 May, Jn. 



8. CHEIRANTHUS, L. WALL FLOWER. (Arabic Jcheyry, the name 

 of a certain plant, and Gr. av6og, flower.) Calyx closed, 2 of the sepals 

 gibbous at base ; petals dilated ; silique terete or compressed ; stigma 

 2-lobed or capitate ; seeds flat, in a single series, often margined. (0). 

 Garden perennials, mostly European. Lvs. undivided. 



C. Cheiri L. St. somewhat shrubby and decumbent at base ; Ivs. entire or 

 slightly dentate, lanceolate, acute, smooth ; branches angular ; petals obovate ; 

 siliques erect, acuminate. r M- Prom S. Europe. A popular garden flower, ad- 

 mired for its agreeable fragrance, and handsome corymbous clusters of orange 

 or yellow flowers. Plant about 2f high. Jn.-j- 



9. LEAYENW6RTHIA, Torr. (Named for Dr. Leavenworth, the 

 discoverer.) Calyx rather erect ; petals cuneate, retuse or truncate ; 



