212 TETRADYNAMIA— SILIQUOSA. Arabis. 



frequently rough, especially on the upper side, with short, spread- 

 ing, cloven or 3-forked bristly hairs ; their outline more or less 

 perfectly lyrate, sometimes merely hastate, rarely only obovate 

 and slightly pinnatifid, always tapering at the base into a slender 

 footstalk, longer than the leaf. Stem-leaves scattered, lanceo- 

 late, or elliptic-lanceolate, obtuse, mostly quite entire and 

 smooth, sometimes hairy; the lower ones having now and then 

 a lateral notch, and more or less of a footstalk. Fl. in terminal, 

 solitary, erect, lax, corymbose, veiy smooth clusters, much elon- 

 , gated, and somewhat wavy, after flowering. Cal. smooth, 

 slightly spreading, membranous at the margin. Pet. twice as 

 long, pale purple, or white, with a horizontal, obovate, entire 

 border. Pods spreading, smooth, linear, tipped with the capi- 

 -tate, somewhat elevated, stigma-, their valves separating at the 

 top and bottom, slightly recurved at each end, but not revolute ; 

 in Ehrhart's specimen they have a slender, not very prominent 

 keel, which may also be perceived in some of my British ones, 

 though not so far advanced. Seeds disposed in a simple row. 

 The suggestions of my learned friend DeCandolle have induced me 

 to be very particular in my description, and to examine carefully 

 how far the real Linnaean Cardamine petrcea differs from our plant. 

 In theflowers and pods I can find no discriminating character, but 

 the leaves of that Cardamine, to which Linnaeus has misapplied 

 synonyms of our Arabis, are truly, as he defines them, " oblong 

 and toothed," at least the radical ones ; being rather linear-lan- 

 ceolate, or partly obovate, with numerous, regular, equal, blunt, 

 prominent teeth, and by no means approaching to a lyrate, much 

 less a hastate, form; the stem-leaves are linear and entire; 

 every part of the plant is perfectly smooth, and seems of a lighter 

 green. Such is the original Swedish specimen, above 6 inches 

 high, with which f.386 of F/. Dan., though not particularly good, 

 appears to agree tolerably well. I have another wild Swedish 

 specimen of a smaller size, about 3 inches high, of which all the 

 leaves are obovate and nearly entire. 

 The plate of Dillenius in Hort. Elth. is excellent. That of Loesel, 

 Fl. Pruss. t. 13, represents the true Sisymbrium arenosum. The 

 leaves in Crantz's figure, as well as in Ehrhart's specimen, are 

 not so deeply sinuated as in my numerous British ones, but their 

 notches are not like the teeth of Cardamine petrcea. 



4. A. ciliata. Fringed Rock-cress. 



Leaves somewhat toothed, smooth on both sides, distantly 

 fringed and bearded ; radical ones obovate. Stem simple. 



A. ciliata. Br. in Ait. H. Kew. v. 4. 1 07. Comp. ed. 4. 1 13. Hook. 



Scot 200. DeCand. Sy St. V 2.225. 

 Turritis ciliata. Willd. Sp. PI. v. 3. 544. Schleich. Cat. 59. 

 T. alpina. Linn. Syst. Veg. ed. 13. 502. Willd. Sp. PI. v. 3.545. 



Sm. in Rees'sCycl.v.36. n.9. Engl. Bot. v. 25. 1. 1746. 

 T. hirsutBe varietas. Linn. Fl. Suec. ed. 2.236. 



