472 BRASSICACEAE 



2. Camelina sativa ( L. ) Crantz. Foliage glabrous or nearly so. Stems erect, 

 3-9 dm. tall, simple or branching above : basal leaves spatulate or oblanceolate, undu- 

 late, or repand : stem-leaves with sagittate-lanceolate blades 2-7 cm. long, acntish, entire, 

 sessile, clasping by the auricled bases : pedicels ascending, 1-1.5 cm. long, enlarged at the 

 apex : sepals oblong, 2.5-3 mm. long : petals yellowish, nearly twice as long as the sepals : 

 silicles pyriform, 6-8 mm. long, somewhat flattened, each tipped with the acute style, the 

 sutures margined. 



In fields and waste places, southern British America and the eastern United States. Naturalized 

 from Europe. Spring. 



7. RORIPA Scop. 

 Aquatic or terrestrial herbs, with erect or creeping stems and glabrous or pubescent 

 foliage, the hairs simple. Leaves alternate : blades toothed, lobed or pinnately dissected. 

 Flowers perfect, in terminal or axillary racemes. Sepals 4, equal, spreading during anthe- 

 sis. Corolla yellow or white : petals 4 (or rarely wanting), usually small, without very 

 manifest claws. Stamens 1-6. Ovary sessile : styles stout or slender : stigmas 2-lobed. 

 Pods of various lengths, terete or nearly so, rarely didymoiis, the valves commonly 1-nerved. 

 Seeds in 2 rows, turgid. Cotyledons accumbent. [Nasturtium R. Br.] AVater-cress. 

 Sturshum. 



Corolla white. 



Blades of all leaves similar : sepals 2-2.5 mm. long : pods fully 1 cm. long. 1. R. Nasturtium. 



Blades of submersed leaves unlike those of emersed leaves : sepals 3 mm. long : 



pods less than 1 cm. long. 2. R. Americana. 



Corolla yellow. 



Annual or perennial from fibrous roots : petals mostly shorter than the sepals. 

 Flowers and pods sessile or nearly so. 



Leaf-blades bipinnatifld : style 2 mm. long : pods 4-7 mm. long. 3. R. Walteri. 



Leaf-blades pinnatifid : style almost wanting : pods 3^ mm. long. 4. R. scssiliflora. 



Flowers and pods manifestly i)edicelled. 

 Stems upright : pedicels 4-8 mm. long. 



Pods subglobose or oval, shorter than the pedicels : stem pubescent. 5. R. hispida. 



Pods linear or narrowly oblong, as long as the pedicels or longer : stem 



glabrous or nearly so. 6. R. palustris. 



Stems diffuse : pedicels 2-4 mm. long. 



Pods subglobose, about 2 mm. in diameter. 7. R. sphaerocarpa. 



Pods oblong, 4-8 mm. long. 8. R. vbtusa. 



Perennial by creeping or horizontal stems : petals mostly surpassing the sepals. 



Leaf-blades pinnatifid : style slender. 9. R. sinuata. 



Leaf-blades j)iiHiately parted : style short and stout. 10. R. sijlvestris. 



1. Roripa Nasturtium ( L. ) Rusby. Perennial, aquatic, glabrous. Stems floating, 



or decumbent and creeping, 1-6 dm. long, simple or branched : leaves alternate ; blades 



unequally pinnate, 2-15 cm. long ; leaf-segments 3-9, irregular, obtuse, the lateral ones 



sometimes nmch reduced, the terminal one larger, usually truncate or cordate at the base : 



racemes elongating in fruit : pedicels finally spreading, 5-15 mm. long : sepals oblong, 



2-2.5 mm. long, obtuse : petals white, about twice as long as the sepals : pods linear, 1-2.5 



cm. long, nearly terete, more or less strongly curved upward. [Nasturtium officinale R. Br.] 



In swampy places or in brooks, Nova Scotia to Idaho, Georgia and Texas. Naturalized from 

 Europe. Spring to fall. Water-cress. 



2. Roripa Americana (A. Gray) Britton. Perennial, aquatic, glabrous or nearly so. 

 Stems 3-8 dm. long, zigzag, liranching above : leaves alternate ; submersed with finely pin- 

 nately dissected blades, readily deciduous ; emersed, oblong-elliptic or linear-oblong, 3-10 

 cm. long, undulate, serrate or pinnatifid : pedicels spreading, 5-15 mm. long, slender : sepals 

 oblong, 3 mm. long, obtuse : petals white, about twice as long as the sepals : pods oblong 

 or oval-oblong, 5-6 mm. long, nearly 1-celled. [Nasturtium lacustre A. Gray.] 



In ponds or in sluggish streams, Quebec to Minnesota, Florida and Louisiana. Summer. 



3. Roripa "Walteri ( Ell. ) Mohr. Annual or biennial, glabrous. Stems more or less 



diffusely branched at the base ; branches ascending or spreading, 1-4 dm. long, branched : 



leaves basal and cauline, 2-10 cm. long ; blades biijinnatifid, the segments of various shapes : 



racemes elongating in fruit : pedicels .spreading or ascending, 1-5 mm. long : sepals about 



1 mm. long : petals slightly longer than the sepals : pods oblong, 8-15 mm. long, slightly 



curved, erect or ascending. [Nasturtium tanacetifolium (Walt.) Hook.] 



In low ground and ditches. South Carolina to Florida, the Indian Territory, Texas and Mexico. 

 Spring. 



4. Roripa sessiliflora (Nutt. ) A. S. Hitchcock. Annual or biennial, glabrous. 

 Stems erect, 2-6 dm. tall, branching above : leaves alternate ; blades lanceolate or ovate 

 to obovate or oblanceolate, 3-15 cm. long, obtuse, coarsely toothed, lobed or ])innatifid, 

 the lower ones petioleil, the upper often sessile : racemes elongating : pedicels mostly 1-2 



