Dicotyls or Exogenous Plants. 53 



3. Genus BAR-BA-RE'-A. — Pod linear, terete or somewhat 4-sided, 

 the valves keeled by a nerve ; flowers yellow. . 



Bar-ba-re'-a bar-ba-re'-a (L.) Macm. {B. vulgaris R. Br.| Winter 

 Cress: Yellow Rocket. — Smooth, lower leaves lyrate, the terminal di- 

 vision large and round, flowers yellow. 



4. Genus l-O-DAN'-THUS. {Tljelypodiian)~Vod terete or nearly 

 so, valve l-nerved, seeds one row in each cell; stout plants, with large 

 purplish flowers. 



l-o-dan'-thus pin-na-tif'-i-dus (Mx.) Prantl. (Thelypodium plnnatifi- 

 diiui Wats.) Rocket Cress. — Root-leaves round or cordate, stem leaves 

 auricled. 



5. Genus ROR'-IP-A. {Xasttirtium.) — Pod short, varying from 

 oblong-linear to globular, terete or nearly so, valves nerveless ; seeds 

 mostly in two irregular rows ; aquatic or marsh plants, with yellow or 

 white flowers. 



A. Petals -ccJu'lc, hvice the length of calyx ; leaves pinnate. 



Ror'-ip-a nas-tur'-ti-um (L.) Rusby. [NastiirtiuDi officiiiale R. Br.) 

 True Water Cress. — Perennial, stems spreading and rooting; leaflets 

 8-11, pods 0-8 lines long. In brooks and ditches. 



A. Petals yelloie 01- yelloii'ish, small. 

 b. Pods longe>- than the pedicels.] 



Ror'-ip-a ses-sil-i-flo'-ra (Nutt.) Hitch. {Nasturtiinn sessiliflornm 

 Nutt.) Water Cress. — Leaves obtusely incised or toothed, obovate or 

 oblong; flowers minute, nearly sessile; pods elongated-oblong, 5-6 

 lines long. 



Ror'-i-pa ob-tu'-sa (Nutt.) Britt. [Nasturtium obtiiston Nutt.) 

 Water Cress. — Leaves pinnatel}- parted or divided, the divisions round- 

 ish and obtusely toothed or repand ; pod linear-oblong to short oval. 



b. Pods mostly shorter tha>i the pedicels] 



Ror'-i-pa pa-lus'-tris (L.) Bess. [Nasturtium palustre DC.) Marsh 

 Cress. — Leaves pinnately cleft or parted or the upper laciniate, the 

 lobes oblong, cut-toothed; pods oblong, ellipsoid. 



Ror'-i-pa his'-pi-da (Desv.) Britt. [Nasturtium palustre var. hispi- 

 diim Gr.) Marsh Cress. — Like the last, but the pods ovoid or globular. 



