Voi,. II.] 



MUSTARD FAMILY 



10. Roripa Armoracia (Iy.) A. S. Hitchcock. 

 Horseradish. (Fig. 1722.) 



Cochlearia Armoracia L. Sp. PI. 648. 1753. 

 Nasturtium Armoracia Fries; A. Gray, Man. Ed. 2, 31. 



1856. 

 Roripa Armoracia A. S. Hitchcock, Spring Fl. Manhat- 



tan, 1 8. 1894. 



Erect, 2-3 high, from deep thick roots. Basal 

 leaves on thick petioles 6 / -i2 / long, the blade oblong, 

 often nearly as long, crenate, sinuate or even pinnati- 

 fid, rough but glabrous; upper leaves smaller, sessile, 

 narrowly oblong or lanceolate, crenate or dentate; ra- 

 cemes paniculate, terminal and axillary; pedicels very 

 slender, ascending, 2 // -3 // long; flowers white, showy, 

 2 // -4 // broad; pods oblong or nearly globose; style 

 very short. 



Escaped from gardens into moist grounds, especially 

 along streams. Frequent. Adventive from Europe. The 

 roots furnish the well-known sauce. Summer. 



ii. Roripa Americana (A. Gray) Britton. 

 Water-cress. (Fig. 1723.) 



Nasturtium natans var. Amerir.anum A. Gray, Ann. 



Lye. N. Y. 3: 223. 1836. 



Nasturtium lacustre A. Gray, Gen. 111. i: 132. 1848. 

 Roripa Americana Britton, Mem. Torr. Club, 5: 169. 1894. 

 Neobeckia aquatica Greene, Pittonia, 3: 95. 1896. 



Aquatic, branching, i-2 long. Immersed leaves 

 2'-3' long, pinnately dissected into numerous fili- 

 form divisions; emersed leaves oblong, obtuse or 

 acute, i/-3' long, entire, serrate or lobed; pedicels 

 3 // -4 // long, slender, widely spreading; flowers white; 

 petals longer than the sepals; style slender, about i" 

 long; pods ovoid, 2" long, i-celled. 



In lakes and slow streams, Ferrisburg, Vt. ; western 

 Quebec and Ontario, northern New York; Sussex Co., 

 N. T-, to Minnesota, south to Florida and Louisiana. 

 Local. Much resembles N. ampliibium of Europe, ex- 

 cept in its white flowers and smaller upper leaves, which 

 are readily detached from the stem. Summer. 



18. CARDAMINE L. Sp. PI. 654. 1753. 



Erect or ascending herbs, with scaly or bulbiferous rootstocks or fibrous roots, entire 

 lobed or divided leaves, and racemose or corymbose white or purple flowers. Stamens 6, 

 rarely 4. Siliques elongated, flat, generally erect; valves nerveless or faintly nerved, elasti- 

 cally dehiscent at maturity. Stipe none. Seeds in i row in each cell, compressed, margin- 

 less; cotyledons accumbeut, equal or unequal. [Greek, heart- strengthening, a name for 

 some cress supposed to have that quality. ] 



A genus of about 75 species, natives of the temperate regions of both hemispheres. 

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

 Flowers 6"-g" broad, white or purplish. I. C. pratensis. 



Flowers i"~4" broad, white. 



Leaf-segments numerous, small, the terminal one 2"-io" wide, narrowed, rounded or subcor- 



date at the base. 



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



Stem leafy; leaves glabrous or very nearly so. 

 Mature pods erect, X"-M!" wide. 



Flowers 2" -2^" wide; plants of swamps, streams, or wet grounds. 



Segments of basal leaves 2"-i2" wide; plant 8' -3 tall. 3. C. Pennsylvanica. 

 Segments of basal leaves X"-i l A" wide; plant 6 -12' tall. 4. C. arenicola. 

 Flowers i"-i l A" wide; plant of dry rocky situations. 5. C. parvtflora. 



Mature pods divergent or ascending, more than 1 A" wide. 6. C. flexuosa. 



Leaf-segments few, large, the terminal one i'-2' wide, deeply cordate. 7. C. Clemalitis. 



& & Leaves entire, toothed, or rarely with i or 2 lateral segments. 



Dwarf, alpine; leaves nearly entire, long-petioled. 8. C. bellidifolia. 



Erect or decumbent; leaves more or less toothed or lobed. 



Flowers purple ; stem erect. 9. C. Douglassii. 



Flowers white. 



Stem erect from a tuberous base. 10. C. bulbosa. 



Stem decumbent, stoloniferous; roots fibrous. 11. C. rotundifolia. 



