BEASSICACEAE. 133 



2. C. sativa (L.) Crantz. Plants glabrous or nearly so, 3-9 dm. tall: leaves 

 nearly similar to those of C. microcarpa: pods broadly obovoid, 6-7 mm. wide: 

 seeds fully 2 mm. long. M. Eather rare, on banks and roadsides. Nat. of Eu. 



5. RADICTJIiA [Dill.] Hill. Annual, biennial, or perennial herbs. Leaf- 

 blades toothed, lobed, or dissected. Baeemes often branched. Sepals 4, broad 

 or narrow. Petals 4, yellow, often scarcely longer than the sepals. Stamens 

 1-6: anthers ovoid to globose. Style very short. Pods short or elongate. 

 Seeds turgid. WATER-CRESS. STURSHUM. 



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

 Pods subglobose or oval, shorter than the pedicels : stem 



pubescent. 1. R. hispida. 



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



stem glabrous or nearly so. 2. R. palustris. 



Perennial by creeping or horizontal stems : petals mostly surpass- 

 ing the sepals. 3. R. sylvestrls. 



1. R. hispida (Desv.) Heller. Stems hirsute or hispid, 3-12 dm. tall: leaf- 

 blades oblanceolate, elliptic, or oblong, pinnatifid or rarely only toothed, 2-18 

 cm. long: ovary globular: pods 2-3 mm. long. Common, in sandy soil, 

 especially along streams. Sum. 



2. R. palustris (L.) Moench. Stems glabrous or minutely pubescent, 2-10 

 dm. tall: leaf -blades oblanceolate to oblong or linear-oblong, pinnatifid, or 

 toothed or repand above, 2-20 cm. long: ovary oblong: pods 5-8' mm. long. 

 Frequent, in low grounds and meadows. Apparently nat. of Eu. Spr. and 

 sum. MARSH-CRESS. 



3. R. sylvestris (L.) Druce. Stems ascending or decumbent, 2-7 dm. long: 

 leaf -blades often ovate or oblong, 4-15 cm. long, pinnately divided, the seg- 

 ments distant, entire or toothed: sepals becoming 2-2.5 mm. long: filaments 

 scarcely longer than the anthers: pods slender, 8-15 mm. long, short-beaked. 

 Common, especially along streams. Nat. of Eu. Spr. and sum. YELLOW- 

 CRESS. 



6. ARMORACIA Gaertn. Perennial erect herbs with long pungent roots. 

 Leaf-blades coarsely toothed or sometimes pinnatifid. Eacemes stiff, with 

 slender pedicels. Sepals rather broad. Petals white, much exceeding the 

 sepals. Stamens 4 or 6: anthers ovoid. Ovary obovoid: style short-columnar: 

 stigma capitate. Pod short and stout. 



1. A. Armoracia (L.) Britton. Stems erect: leaf -blades various, those of the 

 basal leaves oblong to oblong-lanceolate, mostly 15-40 cm. long, irregularly 

 crenate, unequally cordate or truncate at the base; those of the cauline leaves 

 smaller and more coarsely toothed or incised: petals white, obovate, 6-8 mm. 

 long: pods 5-7 mm. long, straight. [Roripa Armoracia (L.) A. Hitchc.] 

 Common, on roadsides and in thickets. Nat. of Eu. Spr. HORSERADISH. 



7. SISYMBRIUM [Tourn.] L. Perennial diffuse aquatic herbs with 

 creeping stems. Leaf -blades pinnately divided. Eacemes lax. Sepals broad. 

 Petals 4, white, much exceeding the sepals. Stamens mostly 6: anthers ovoid. 

 Ovary narrow: style very stout: stigma discoid. Pod elongate, linear. 



1. S. Nasturtium-aquaticum L. Stems diffuse or floating, 1-6 dm. long: leaf- 

 blades unequally pinnate, 2-15 cm. long, the segments irregular: petals white, 

 3-4 mm. long: pods linear, 10^25 mm. long, curved. [Roripa Nasturtium (L.) 

 Eusby.] Common, in springs and slow streams. Nat. of Eu. Spr.-fall. 

 WATER-CRESS. 



8. ERYSIMTJM [Tourn.] L. Annual or perennial herbs. Leaf-blades 

 entire, lobed or pinnatifid. Eacemes elongating, strict. Sepals 4, rather nar- 



