30 CRUCIFEILE. 



high, angular, branched. Flowers larger than in the preceding. Introduced from 

 Europe. 



14. ARABIS. Linn. Wall Cress. 



SaiJ to have derived its name from Arabia, its native country. 



Sepals erect. Petals unguiculate, entire. Pod linear 7 

 plane; valves flat, 1-nerved in the middle. Seeds in a single 

 row in each cell, usually margined or winged. — Annual and 

 biennial plants with white floicers. 



1. A. Canadensis, L. SvJde Pod. 



Stem leaves sessile,, oblong-lanceolate, acuminate; the lower, toothed: pediceU 

 3-times as long as the calyx, pubescent reflexed in fruit ; petals twice the length of 

 the calyx, oblong-linear: pods pendulous, subfalcate, veined: seeds winged. 



Rocky situations. May — Aug. Stem 2 to 3 feet high, slender, round, smooth. 

 leaves 1 to 3 inches long. J^ as wide, sessile and clasping. Flowers in long terminal 

 racemes, small, white. Pods long, drooping, resembling a sickle blade. 



2. A. lyrata, L. American Roch Crc?s. 



Stem diffusely branched, low; stem leaves linear or spatulate, entire, smooth and 

 glaucous: radical leaves lyrately pinnatifid, often pilose: pedicels aomewhsi spread- 

 ing ; petals twice the length of the calyx ; pods erect, spreading, with a short, 

 straight style ; seeds marginless. 



Rocky hills. April — June. Stem 8 to 12 inches high, often many united at the 

 base. .Root-leaves numerous, rosulate, 1 to 3 inches long, % as wide, petiolate. 

 Flowers middle size, white or rarely pale purple. 



3. A. LMVIGATA, DC. Smooth Wall Cress. 



Erect, smooth and glaucous; radical leaves obovate and oblong, tapering to a 

 petiole, sinuate-dentate ; stem-leaves linear-lanceolate, amplexicaul, sparingly cut- 

 toothed or entire : petals scarcely larger than the calyx : pods long and narrow, 

 re-curved, spreading and pendulous. 



Rocky places. May. Stem 1 to 2 feet high, round, smooth, simple, or branched 

 above. Foot-leaves often purplish, % to 1% inch long, half as wide, with acute 

 teeth. Flowers white, few, small, in corymbed racemes. Fod 2 inches long, very 

 narrow. 



4. .A. hirsuta, DC. Hairy Wall Cress. 



Erect, branching; leaves dentate, pubescent, or scabrous; radical- ones ovate- 

 oblong, tapering to a petiole; stem leaves ovate, lanceolate, sagittate; ptdicd* as 

 long as the calyx: pod straight, erect. 



Low. rocky grounds. Xot common. May, June. St-em 6 to 12 inches high ; 2 or 

 more from the same root; round, hairy at the base, dividing into slender parallel 

 branches. Leaves scarcely dentate. Beanie, with heart-shaped or sagittate basefl- 

 Flowers small, greenish white. Fod 1 to 2 inches long. 



15. IODAXTHES. Torr. & Gray. False Rocket. 



Gr. iodes. violet colored ; and anthos, flower. 



Pod linear, elongated, terete. Seeds in a single row in 

 each cell, margined. Style thick. Stigma capitate. Claws 

 of the violet-purple petals longer than the calyx. — A smooth 

 perennial, with showy flowers in panicled racemes. 



