rO TETRADYNAMIA. SliTQCOSA. 



natifid; siliques pedunculate, slender and spreading", most- 

 ly scabrous. Hab. Not unconnmon on the bank's oitjie 

 Ohio, from Le Tan's rapids downwards. Obs. Kooi pe- 

 i-enmal. Stem 2 or 3 feet higji, s'-mpie or branched, siiiooth, 

 angular and grooved. Leaves ovate-lanceolate, sessile, re- 

 mote, sharply and unequally toothed, thin and naembra- 

 naceous, the under side minutely sCabrous, lower stem 

 leaves amplexicaule and pinnatifid only towards tiie at- 

 tenuated base; (about 3 inches loHg, and 1 wide.) Ra- 

 ceme mostly terminal and simple, occasionally axillary. 

 Peduncle very distinct, in the fruit half an inch long. Ita- 

 chis, peduncle and silique usually scabrous. Calix ovate, 

 a little purplisli, leaves membranaceous on the margin, 

 shorter than the claws of liie petals, 2 of them d:slincl'y 

 gibbous at the base. Petals obtusely obovate, entire, pale 

 purple, small. Anthers revoluie. Stigma a little dilated 

 at the base, lobes conniveut. Silique rather compressed, 

 torulose, near 2 inches long, and about the thickness of an 

 ordinary sowing thread, shortly rostratei curved upwards 

 in a line with the peduncle. 



A genus of about 20 species, with the above exception, 

 exclusively indigenous to the soutli of Europe, and Nof- 

 thern Africa. 



464. ARABIS. L. (Wall-Cress.) 



« Silique linear (mostly compressed) crowned 

 with the subsessile stigma; valves venose or 

 nerved. Seeds disposed in a single series. 

 Cotyledones accumbent. Calix erect." R.Brown. 

 Hort. Kew. 4. p. 104. 



Species. 1. \. alpina. 2. thaliana. 3. reptans. 4. 

 It/rata. Perennial. Stem and upper entire linear leaves 

 smoo"h and glaucous; radical le;(ves lyrate, often pilose; 

 pcdancle spreading, si licjue erect and compressed. 5. strtc- 

 ta. 6[caiHid.iis-is. Jl.falcata. M,ch. 7- Jtenduh.P Leaves sa- 

 gittate oblong, amplexicaule, entire and smooth; silique 

 a icipiird, linear, pendulous. 11a o. Near Fort Mandan on 

 the b.mks of tlie .Miss^Juri. Stem itearly simple, spike 

 very long. Calix and corolla erect. 8. rhoml-oidea, A. 

 hi/hosay .Muhlenberg- Carclamine rotiimUj'uUa? Midi. Obs. 

 Kadical leaves roundisli, upon long petioles, proceeding 

 Irom the bulb or tuber, cauline subsessile, rhomboid-ovate, 

 sparingly and incisely toothed; flowers very much like 

 those of Canlamlne pn.ti'Hsis^.hut white; siliques divaricate, 

 upon very long peduncles, linear, very smooth, flat, and. 



