CLASS XV. ORDKtt II.] ARABIS. 903 



raceme of about six flowers, erect. Calyx erect, smooth, of four equal 

 ovate oblong purplish pieces. Corolla of four ovate oblong white or 

 yellowish petals, about as long again as the calyx. Stamens with 

 simple awl-shaped filaments and small ovate yellow anthers, of two 

 cells. Stigma sessile, obtuse. Fruit an erect linear smooth siliqua, 

 somewhat compressed, the valves marked with prominent longitudinal 

 veins. Seeds ovate, with a narrow margin, winged at the apex. 



Habitat. — St. Vincent's rock, near Bristol ; rare. 



Perennial ; flowering in May. 



2. A, petrcB'a, De Cand. (Fig. 1042.) Alpine Rock-cress. Stem 

 erect, smooth ; leaves smooth, or slightly hairy, the radical ones 

 obovale, petiolated, deeply toothed or lobed, the upper ones oblong 

 linear, entire, sessile ; petals spreading ; siliqua slender, linear, spread- 

 ing ; valves with a very slender longitudinal vein. 



Hooker, British Flora, ed. 4. vol. i. p, 252. — A. hispida, Linn. — 

 English Flora, vol. iii. p. 211. — Lindley, Synopsis, p. 24.— Cardamine 

 hastulata. — English Botany, t. 469. — C. petraa, Huds. 



Root tapering, with slender branched fibres, tufied at the crown. 

 Stems mostly several, from three to four inches high, erect, or ascend- 

 ing, simple or branched, slender, round, smooth, or slightly hairy at 

 the base, leafy. Leaves dark green, smooth, or slightly hairy, the 

 radical ones numerous, tufted, obovate, on a slender footstalk, toothed 

 or lobed in a lyrate or pinnatifid manner, the upper ones simple, sessile, 

 linear, oblong. Inflorescence terminal sub-corymbose racemes, be^ 

 coming much elongated. Pedicles short. Calyx of four smooth ovate 

 pieces, with a narrow membranous margin. Corolla pale purple or 

 white, with dark veins, the claw narrow, as long as the calyx, the limb 

 spreading. Stamens with simple filaments and small two celled 

 anthers. Style sessile, obtuse. Fruit slender, narrow, linear, smooth, 

 the valves with very slender longitudinal veins. Seeds small, ovate. 



Habitat. — Alpine rocks; North Wales, frequent in Scotland, Ross- 

 shire and Sutherland. — Prof. Graham. 



Perennial ; flowering in June and July. 



3. A. ciliaHa^ Brotrni. (Fig. 1043.) Fringed Rock-cress. Stem erect, 

 smooth ; leaves smooth, ciliated on the margins, ovate, oblong, entire 

 or toothed, the radical ones tapering into a short footstalk, the upper 

 sessile, rounded at the base ; petals erect ; siliqua narrow, linear, com- 

 pressed, erect ; valves with a prominent rib, and slender longitudinal 

 veins. 



English Flora, vol. iii. p. 212.— Hooker, British Flora, ed. 4. vol. i. 

 p. 252.— Lindley, Synopsis, p. 24.—Turritis alpina, Linn.— English 

 Botany, t. 1746. 



Root slender, tapering. Stem erect or ascending, from two to four 

 inches high, round, slender, simple, smooth, leafy. Leaves a dark 

 green, smooth and shining on both sides, the margins ciliated with 



