CR UCI FERAE. 453 



eels slender, 6 mm. long in fruit; flowers yellow, 4-6 mm. broad; pods linear, or 

 linear-oblong, 2-6 times as long as thick, about equalling the pedicels, spreading 

 or curved; style I mm. long or less. In wet places, nearly throughout N. Am. ex- 

 cept the extreme north. Apparently nat. from Europe. May-Aug. 



7. Roripa hispida (Desv.) Britton. HISPID YELLOW-CRESS. (I. F. f. 1718.) 

 Resembling the preceding, but often stouter, sometimes 12 dm. high, the stem, 

 branches, petioles and veins of the lower surfaces of the leaves hirsute. Leaves 

 lyrate-pinnatifid ; pedicels slender, spreading, about 6 mm. long, longer than the 

 globose or ovoid pod, which is 1-2 times as long as thick. In wet places, N. B. to 

 Br. Col., Fla. and N. Mex. Summer. 



8. Roripa curvisiliqua (Hook.) Bessey. CURVED-FRUITED CRESS. (I. F. f. 

 1719.) Annual or biennial, sparingly pubescent or glabrous; stems 1.5-4.5 dm. 

 high. Leaves oval or oblanceolate, pinnatifid, pinnately lobed or toothed, the 

 lower 2-8 cm. long; flowers light yellow, 4 mm. broad in short racemes; petals 

 rather longer than the sepals; style short; pods linear, 8-16 mm. long, less than 

 2 mm. wide, strongly curved upward; pedicels spreading or ascending, 2-4 mm. 

 long. In moist soil, Mont, to Br. Col. and Cal. Not certainly known within our 

 range. May-Aug. 



9. Roripa sessiliflora (Nutt.) A. S. Hitchcock. SESSILE-FLOWERED CRESS. 

 (I. F. f. 1720.) Annual or biennial, erect, glabrous, 2-5 dm. high. Leaves 

 petioled, the lower 7-10 cm. long, obovate or oblong, obtuse, crenate, lobed or 

 pinnatifid, with obtuse lobes; flowers yellow, 2 mm. broad, nearly sessile; pods 

 very slightly pedicelled, 6-12 mm. long, 2 mm. broad, narrowly oblong; style 

 very short. In low grounds, Tenn., III. and Iowa to Kans., Fla. and Tex. 

 April-June. 



10. Roripa Nasturtium (L.)Rusby. WATER-CRESS. (I. F. f. 1721.) Aquatic, 

 glabrous, rooting from the nodes. Leaves odd-pinnate, of 3-9 segments, the 

 terminal one larger than the lateral, all obtuse, ovate or oval, or the terminal one 

 nearly orbicular; flowers white, 4-5 mm. broad; pods 1-3.5 cm - l n g. 2 mm - wide, 

 slightly curved upward, on pedicels of about their length ; seeds in 2 rows. In 

 brooks and streams, N. S. to Manitoba, Ore., Va. and Neb. and Ariz. Nat. from 

 Europe. April-Nov. 



11. Roripa Armoracia (L.) A. S. Hitchcock. HORSERADISH. (I. F. f. 1722.) 

 Erect, 6-10 dm. high, from deep thick roots. Basal leaves on thick petioles 

 1.5-3 dm. long, the blade oblong, often nearly as long, crenate, sinuate or even 

 pinnatifid, rough but glabrous; upper leaves sessile, narrowly oblong or lanceolate, 

 crenate or dentate; racemes paniculate; pedicels slender, ascending, 4-6 mm. 

 long; flowers white, 4-8 mm. broad; pods oblong or nearly globose; style very 

 short. Escaped from gardens into moist grounds, especially along streams. 

 Adventive from Europe. Summer. 



12. Roripa Americana (A. Gray) Britton. LAKE WATER-CRESS. (I. F. f. 

 1723.) Aquatic, branching, 3-6 dm. long. Immersed leaves 5-8 cm. long, 

 pinnately dissected into numerous filiform divisions; emersed leaves oblong, 2-8 

 cm. long; pedicels 6-8 mm. long, slender, spreading; flowers white; style slender, 

 about 2 mm. long; pods ovoid, 4 mm. long, i-celled. In lakes and slow streams, 

 Vt. and Quebec to Ont., Minn., Fla., La. and Ark. Summer. 



19. CARDAMINE L. 



Erect or ascending herbs, with scaly or tuberiferous rootstocks or fibrous roots, 

 entire lobed or divided leaves, and racemose or corymbose white or purple flowers. 

 Stamens 6, rarely 4. Siliques elongated, flat; valves nerveless or faintly nerved, 

 elastically dehiscent at maturity. Stipe none. Seeds in I row in each cell, 

 compressed, marginless; cotyledons accumbent. [Greek, heart-strengthening.] 

 About 75 species, natives of temperate regions. 



* Leaves pinnately divided, or some of them of but a single terminal segment. 

 Flowers 1-2 cm. broad, white or purplish. i. C. pratensis. 



Flowers 2-8 mm. broad, white. 



Leaf-segments numerous, small, the terminal one 4-20 mm. wide, narrowed, rounded 

 or subcordate at the base. 



Leaves nearly all basal, pubescent. 2. C. hirsuta, 



Stem leafy ; leaves glabrous or very nearly so. 



