CRUCIFER^. 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 Moimtains. 

 April — ^Jmie. @. — iitem 8 — 12 inches high. Flowers large, white, or rarely 

 pale purple. Lyre-leaved Wall-cress. 



4. A. Icevigata 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 Iccvigata 

 Willd. 



Rocky places. N. S. May. (§). — Stem 1 — 3 feet high. Flowers few, small, 

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

 the extremity into a verj-^ short style. Smooth Wall-cress. 



5. A. dentata Torr. tf« 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 ; cauUne 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 Wall-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. Null. @. — Radical leaves somewhat hairy. Pod about 3 

 inches long. Heterophyllous Wall-cress. 



7. A. Canadensis Linn. : cauUne 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.fakata Mich. Pursh. A. mollis JRaf. 



Rocky situations. Can. to Flor. W. to Miss. June. ©. — Stem ,1 — 3 feet 

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



SicTdePod. 



14. CARD AMINE. Z^wwi.— Bitter-cress. 



(From the Greek KupSia, the heart, and Sajxao), to fortify ; on account of its sup- 

 posed strengthening quaUties.) 



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. Arabis rhomboidea 

 Pursh. 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. ^ Gr. 



