CRUCIFER.E. 29 



3. A. lyrata Linn. : stem somewhat branched, hairy at base ; radical 

 leaves lyrate-pinnatifid, often pilose ; those of the stem linear or spatulate, 

 entire, smooth ; pedicels somewhat spreading ; pod rather erect and nearly 

 straight. Sisymbrium arabidoides Hook. 



On rocks. Throughout the N. S. and Can. W. to the Rocky Mountains. 

 April June. (^J). Stem 8 12 inches high. Flowers large, white, or rarely 

 pale purple. Lyre-leaved Watt-cress. 



4. A. lavigata D. C. : erect, glabrous and glaucous ; radical leaves, 

 obovate, petioled, sinuate-dentate ; cauline linear, sessile, very entire ; pod 

 long and narrow, recurved-pendulous ; seeds margined. Turritis l&vigata 

 Wittd. 



Rocky places. N. S. May. .Stem 13 feet high. Flowers few, small, 

 in corymbed racemes. Pod 2 inches long, linear, somewhat tortuous, tapering at 

 the extremity into a very short style. Smooth Watt-cress. 



5. A. dentata Torr. fy Gr. : rough with a stellate pubescence ; radical 

 leaves obovate, tapering at base into a petiole which is as long as the la- 

 mina, irregularly dentate ; cauline oblong, clasping ; pod short, spreading ; 

 seeds slightly margined. 



Sandy grounds. N. Y. to Miss, and Arkansas. May. (J). Stem a foot or 

 more high, slender, decumbent at base. Leaves scabrous beneath. Flowers dull 

 white. Toothed WaU-cress. 



6. A. heterophylla Nutt.: nearly smooth; radical leaves spatulate, 

 toothed ; upper ones linear, sessile, entire ; pod long and spreading ; petals 

 linear-oblong, exceeding the calyx. 



Maine or N. H. Nutt. d). Radical leaves somewhat hairy. Pod about 3 

 inches long. Heterophyllous Watt-cress. 



7. A. Canadensis Linn. : cauline leaves sessile, oblong-lanceolate, acu- 

 minate, somewhat toothed ; pedicels thrice as long as the calyx, pubescent, 

 reflexed in fruit ; pod pendulous, subfalcate, nerved ; seeds with a broad 

 wing. A.falcata Mich. Pursh. A.mollisRaf. 



Rocky situations. Can. to Flor. W. to Miss. June. (). Stem 1 3 feet 

 high. Flowers white, in long terminal racemes. Pod very long. 



SicJclePod. 



14. CARDAMINE. Linn. Bitter-cress. 



(From the Greek KapSta, the heart, and <5a/*aw, to fortify ; on account of its sup- 

 posed strengthening qualities.) 



Pod linear; valves flat, nerveless, often opening elastically. 

 Seeds ovate, not margined ; funicle of the hilum slender. 

 * Leaves undivided. 



1. C. rhomboidea D. C. : root tuberous ; leaves ovate-rhomboid, obscurely 

 repand-toothed, smooth ; lower ones on long petioles^ AraMs rhomboidea 

 Purs/i. Pers. 



Low grounds. From Hudson's Bay to Geor. W. to the Rocky Mountains. 

 May, June. %.. Stem 9 18 inches high, erect, smooth, simple. Flowers in 

 terminal racemes, large, white. Spring-cress. 



2. C. rotundifolia Mich. : root fibrous ; stem weak, procumbent ; leaves 

 Buborbicular, subdentate, smooth, petioled ; pod spreading, slender, with a 

 long style. C. rhomboidea var. Torr. fy Gr. 



