TETRADYNAMIA— SILIQUOSA. Arabis. 211 



side of the Avon, about a mile below the hot-wells, but sparingly. 

 Mr. W. Claijfield and Mr. Dyer. I have also seen it on the tine 

 turf just below the hot- wells. 



Perennial. May. 



Root simply tufted, very long, tapering and fibrous, not creeping, 

 certainly perennial. Stems for the most pnrt several, erect, or 

 ascending, from 3 to 6 inches high, round, leafy ; the central 

 one usually branched ; all rough in the lower part with mostly 

 simple, spreading or deflexed, bristly hairs. Radical leaves nu- 

 merous, obtuse, dark green, purplish underneath, deeply toothed 

 or sinuated in a lyrate manner, rough with simple, rarely forked, 

 rigid hairs ; stem-leaves scattered, smaller, and more entire, 

 coarsely and sparingly fringed. Fl. few, corymbose, erect, 

 cream-coloured, rather large, their petals upright. Cal. smooth, 

 reddish, scarcely if at all spreading. Pods slender, erect, straight, 

 smooth, slightly corrugated, on short smooth stalks, of which 

 some of the lowermost are accompanied by small linear leaves, 

 looking like hracteas, but not properly such. 



3. A. liispida. Alpine Rock- cress. 



Radical leaves lyrate or hastate, smooth or bristly, tufted ; 

 stem-leaves lanceolate, entire, scattered, mostly smooth. 

 Petals spreading. Root branched at the crown. . 



A. hispida. Linn. Suppl. 298. IVilld. Sp.Pl.v.'S.b38. Fl.Br.7\3, 

 Comp. ed. 4.113. Br. in Ait. H. Kew. v. 4. 1 OG. Hook. Scot. 199. 



A. petraea, a, /3, y. DeCand. Syst. v. 2. 229, 230. 



A. thaliana. Crantz Austr.fasc. 1 . 41 . ^ 3./. 2. 



A. crantziana. Ehrh. Herb. 78. Willd. Sp. PL v. 3. 535. 



Sisymbrium arenosum. Linn. Fl. Suec. ed. 2. 233 ; 7iot of Sp. PI. 



Cardamine petreea. Huds. 293. fVith. 577. Lightf. 347. t. 15. 

 /. 2. Jacq. Enum. 120 ; from the author. Host Syn.367. 



C. petraea cambrica, nasturtii facie. Dill. Elth. 70. t.Q\.f. 71. 



C. hastulata. Engl. Bot. v. 7. t. 469. Fl. Dan. t. 14G2. 



Nasturtium petrseum Johnsoni. Raii Syn. ed. 2. 174. ed.3. 300. 

 Pliik. Almag. 26 1 . Phyt. t.\0\.J.3; very bad. 



Welsh Rock Cress. Petiv. H. Brit. t. 50. f. 3. 



On lofty alpine rocks of Whales and Scotland, in moist places. 



First observed in various ])arts of North Wales, by ^Ir. Lhwyd, 

 before 1090, Ray. Gathered in Scotland, by Mr. Lindesav, in 

 1728. 



Perennial. July. 



Root tapering, running deep into llie ground, subdivided and 

 tufted at the crown, not at all creeping. Slon one, or more, 3 

 or 4 inches higli, erect or ascendinf:j,sim])Ie orsligluly l)ranched, 

 round, leafy, frequently quite smootli, sometimes rougli towards 

 the base, with simple si)readinc^ hairs. Radical Imves numerous, 

 about half an incli long, composing several lax tufts, slightly suc- 

 culent, deep green, sometimes nearly or quite smooth, but most 



I' J 



