CRUCIFERAE. 



[Voi,. II. 



i. Roripa sylvestris (L,.) Bess. 



Creeping Yellow Water-cress. 



(Fig. 1713.) 



Sisymbrium sylvestre L,. Sp. PI. 657. 1753. 

 Nasturtium sylvestre R. Br. in Ait. Hort. Kew. Ed. 



2, 4: no. 1812. 

 Roripa sylvestris Bess. Enum. 27. 1821. 



Perennial, glabrous; stems creeping, branches 

 ascending. Leaves pinnately divided or deeply 

 pinuatifid, petioled, $'-$' long, i'-2' broad, 

 ovate in outline, the divisions obovate, or ob- 

 long, toothed or lobed, the terminal one often 

 somewhat larger than the lateral; pedicels slen- 

 der, 3 // long; flowers yellow, 3 // -4 // broad; pod 

 linear, 4 // -6 // long; style very short. 



In low grounds and waste places, occasional from 

 Massachusetts to Virginia and Ohio. Adventive or 

 naturalized from Europe. Native also of northern 

 Asia. Summer. 



2. Roripa sinuata (Nutt.) A. S. 

 Hitchcock. Spreading Yellow- 

 cress. (Fig. 1714-) 



Nasturtium sinuatum Nutt.; T. & G. Fl. N. A. 



1:73. 1838. 

 Rortpa sinuata A. S. Hitchcock, Spring Fl. 



Manhattan, 18. 1894. 



Perennial, diffuse, glabrous, the branches 

 ascending. Leaves oblong, lanceolate, or 

 oblanceolate, 2 / -3 / long, %'-i f wide, piuna- 

 tiful, the lobes linear or oblong, obtuse, en- 

 tire, or sparingly dentate; pedicels slender, 3" 

 long; flowers yellow, about 2" broad; pods 

 linear-oblong, sometimes slightly curved* 

 4 // -6 // long; style slender, i // -i / '4 // long. 



Banks of the Mississippi, Minnesota to Mis- 

 souri, west to the Sierra Nevada. The eastern 

 forms referred to this species may be specifically 

 distinct. June -Sept. 



3. Roripa obtusa (Nutt.) Britton. 



Blunt-leaved Yellow-cress. 



(Fig. 1715.) 



Nasturtium oblusum Nutt. ; T. & G. Fl. N. A. 



i:74- 1838. 

 Rorif>a obtusa Britton, Mem. Torr. Club, 5: 



169. 1894. 



Annual or biennial, diffuse, much 

 branched, the branches ascending or erect. 

 Leaves oblong or oblanceolate, 2 / -4 / long, 

 pinnately divided, or pinnatifid, the lobes 

 obtuse, repand-toothed, or sometimes entire; 

 pedicels i // -2 // long; flowers yellow, i" 

 broad or less; pods narrowly oblong, or lin- 

 ear, 3 // -5 // long, ascending; style YI" long. 



In low grounds, Michigan, south to Texas, 

 west to the Pacific Coast. April-Aug. 



