228 Obdbb 13.— ORUCIPER^. 



1. NASTtfRTIUM, E. Br. Water Cress. (Lat. nasus tortus ; from 

 the eflfect of these acrimonious plants upon the nose.) Sepals equal at 

 base, spreading; siliques subterete, generally curved upwards, some- 

 times shortened so as to resemble a silicle; valves veinless; seeds 

 small, lens-shaped, go, in a double row (0=). — Aquatic plants with 

 pinnate or pinnatifid Ivs. 



* Petals wliite. Siliques vatber long (10—12") No. 1 



* Petals yellow. Siliques shortened (4—8"), but longer than the pedicels (a). 



* Petals yellow. Siliques or silioles (1—6") shorter than the pedicels (b). 



a Leaves pinnate or pinnatifid. Diffusely branched Nos. 2, 8 



a Leaves iyrate, or merely toothed. Stems erect Nos. 4, 5 



b Petals not longer than the calyx, obscure Nos. 6, 7 



b Petals longer than the calyx, bright yellow Nos. 8, 9 



1 N. ofScinale E. Br. English "Water Ceess. Lvs. pinnate, Ifts.' ovate, sub- 

 cordate, repand; petals white, longer than the calys. — 1( Brooks and springy 

 places, rare. (Yellow Springs, 0.) Sts. decumbent, thick, branching, 6 — 12' long. 

 Lfts. 3 — 1, broad, mostly rounded at base, obscurely toothed, terminal one 

 largest. Fla. corymbed. Siliques hardly 1' long. Occasionally cultivated for 

 salai May, Jn. § \. 



2 N. tanaoetifolium Hook. Tansbt-leaved. Tipper lea/segm. confluent, lower 

 distinct, oblong or roimdish, sinuate-toothed teeth obtuse ; pods linear-oblong. — (D 

 Damp soils, Ga. and Pla., W. and N. "W. to the Miss. Sts. smooth, diffusely 

 branched from the base, 4 — 12' high. Root lvs. 2^—4' long, narrow, regularly 

 pinnate with 19 — 15 segm. in the larger plants, the 3 upper segm. often conflu- 

 ent. Fls. minute. Pods 4 — 8" long, slightly curved, on ped. J as long, and 

 tipped with a distinct but short style. Mar., May. 



/3. OBTUSUM. Lfts. mostly distinct, oval, obtuse ; pods shorter (3 to 5"), twice 

 longer than pedicel. (N. obtusum, Nutt.) 



3 N. Walteri. Segm. of the lvs. aS distinct, narrow, with a few linear, acute lobes 

 or teeth; pods linear, — 11 1 Ga. (Feay and Pond.) and Car. Et. thick, blackish, 

 with many strong fibres. Lvs. numerous, mostly radical or subeauline, 1 — 2' 

 long, finely dissected, the terminal segm. 3-lob6d. Sts. branched fi'om the base 

 (only?), 3 — 5' high, puberulent. Fls. minute. Pods slender, about 5" long, 

 ped. half as long ; style distinct. Mar., Apr. (Sisymbrium "Walteri Ell.) 



4 N. limosum Nutt. Iais. kmceolaii, toothed, lower ones pinnatified at base 

 (Iyrate), upper entire at base; pods elliptic-oblong (3— 4").— <D Edges of the 

 Miss., La. (Hale.) Glabrous. Sts. erect, simple, branched only at top, 10 — 16' 

 high. Lvs. aU cauline and petiolate, the lower irregularly divided at base, where 

 they touch the water. Eac. several. Fls. minute. Pods on very short pedicels, 

 with styles much shorter. Apr., May. Hardly distinct fi'om- the next. 



5 N. sessilifldrum Nutt. Z/vs. cuneaie-obovaie, repandly toothed or sub-entire ; 

 pods linear-oblong (5 — 6"), subsessile. — © Banks of the Miss. Glabrous. Sts. 

 erect, nearly simple. Lvs. attenuated at base, those of the stem nearly 

 entire. Ms. minute. Eac. elongated in fi'uit, both pods and stigmas almost 

 sessile. Apr. — Jn. 



6 N. paltiBtre DO. Maesh Cress. CHahrous ; lvs. pinnately lobed, amplexical, 

 lobes confluent, dentate ; rt. fusiform ; pet. as hng as the sepals ; silicle spreading, 

 turgid, twice longer than widc-^H In wet places. St. 1 — 2f high, erect, branched 

 above. Lvs. 2 — 3' long, all more or less pinnatified, with the terminal lobe 

 large, ovate. Els. numerous, small. Silicle 3" long, pedicels tvrioe as long, often 

 deflexed. Jn. — Aug. 



7 W. hfspidum DC. Villous; hs. runcinaie-pinnaiified, lobes dbtusety .dmtate; 

 ailicles tumid, ovoid or globula/r, the pedicels longer, ascending; pet. scarcely as 

 long as the calyx, — @ Banks of streams N. H. to Penn. Stem angular, branched, 

 1 — 3f high, with many paniculate racemes above. Lvs. 3 — 6' long. Els. 

 minute. Silioles 1" long, on pedicels 2 — 3" long and somewhat spreading. Jn. 

 —Aug. 



8 N. sylv^stre E. Br. Wood Cress. Z/us. pirmateh/ divided, segm. serrate or in- 

 cised; pods linear, style very short. — % "Wet meadows, near Philadelphia (Nutt); 



