902 ARABIS. [CLASS XV. order ii. 



Root tapering, and with many branched fibres. Stem erect, about 

 two feet high, smooth, angular, leafy, branched. Leaves smooth, 

 dark green, paler beneath, the radical ones lyrate, with the terminal 

 lobe roundish, heart-shaped, entire, crenated, lobed or waved, the 

 lateral lobes ovate or oblong, entire or waved, the upper leaves pin- 

 natifid, with spreading linear oblong lobes, the terminal one scarcely 

 broader than the others. Inflorescence a terminal sub-corymbose 

 raceme of a few small yellow flowers, shortly forming an elongated 

 raceme, the pedicles short, thick. Calyx ovate oblong, with a narrow 

 membranous margin, equal at the base. Petals smaller than the last 

 species, paler, the claw narrow, about the length of the calyx, the 

 limb obovate, spreading. Stamens with awl-shaped filaments and 

 yellow ovate oblong two celled anthers. Fruit about three inches 

 long, linear, obtuse, with the nearly sessile stigma, smooth, the valves 

 with a prominent dorsal rib. Seeds numerous, ovate. 



Habitat. — Waste places in the South of England. 



Biennial ; flowering from April to October. 



This species is much more palatable than the last as a vegetable, 

 and is commonly cultivated in gardens under the name of American 

 Cress; and it has probably escaped from cultivation, and become 

 a naturalized plant. It is frequent on [the Continent iu moist fields, 

 on banks of rivers, &c. 



GENUS XX. ARA'BIS Linn. Rock-cress. 



Nat. Ord. Crccif'er^. Juss. 



Gen. Char. Siliqua linear, valves flat or convex, with a longitudinal 

 rib or vein. Calyx erect. Stigma obtuse, entire, or sub-emar- 

 giuate. Seeds oval or orbicular, compressed. Cotyledons accum- 

 bent. — (See Fig. 1, p. 871.) — So named because originally an 

 Arabian genus. 

 1. A. stric'ta, Huds. (Fig. 1041.) Bristol Rock-cress. Leaves 

 oblong, ovate, the radical ones lyrato-sinuated, obtusely toothed, taper- 

 ing into a footstalk, the upper ones sessile ; racemes of about six 

 flowers; calyx smooth; petals erect; siliqua linear, erect, compressed, 

 the valves with prominent longitudinal veins. 



English Botany, t. 614. — English Flora, vol. iii. p. 210. — Hooker, 

 British Flora, ed. 4. vol. i. p. 252. — Lindley, Synopsis, p. 24. 



Root tapering, and with numerous branched fibres. Stems mostly 

 numerous, erect or ascending, from three to six inches high, round, 

 leafy, simple or branched, smooth above, hairy below, with simple 

 spreading hairs. Leaves a dark green, roughish, with simple or 

 forked hairs, the radical leaves numerous, spreading, purplish beneath, 

 deeply toothed or lobed in a lyrate manner, tapering into a footstalk, 

 the upper ones smaller, sessile, distant. Inflorescence a terminal lax 



