30 DICOTYLEDONOUS PLANTS. 



Ktaniens as long as the petals ; pod suberect, on longish pedicels, slen- 

 der. 



HAB. Dry hillg. N. S. April, May. Q.Stcm 2 8 inches 

 high. Flowers in a corymb, white. Common Watt-cress. 



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

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

 smooth ; pedicels somewhat spreading ; pod erect. 



HAB. Fields and hills. Throughout the N. 8. and Can. and W. to 

 Rocky mountains. April, June. <J. Stem8 12 inches high. 

 Flowers large, white. Dr. Hooker supposes this plant to be 

 identical with the European A* petraa. 



5. A. lamgata De Cand. : erect, glabrous and glaucous ; radical 

 leaves, obovate, petioled, sinuate-dentate ; stem leaves linear, sessile, 

 very entire ; pod erect ; seeds margined. Turritis lamgatd Wittd. 



HAB. Rocky places. N. S. May. 1{. Sterna foot to 18 in- 

 ches high. Flowers few, small, in corymbed racemes. Pod 2 

 inches long, linear, quite erect, tapering at the extremity into a 

 very short style. 



G. A. canadensis Linn. : stem leaves sessile, oblong-lanceolate, acu- 

 minate, somewhat toothed; pedicels thrice as long as the calyx, pubes- 

 cent, reflexed in the fruit ; pod pendulous, subfalcate, nerved ; seeds 

 with a broad wing. A.falcata Mich. Pursh. A. mollis Rqf. 



HAB. Rocky situations. Can. toGeor. June. It. Stem 1 2feet 

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



Sicklt Pod. 



15. CARDAM1NE. Lmn. 



Pod linear ; valves flat, nerveless, often opening elastical- 

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



Tetr adynamia. Siliquosa. 



* Leaves undivided, 



1. C. rhomboidea De Cand. : root tuberous ; leaves ovate-rhomboid, 

 obscurely repand-toothed, smooth, lower ones on long petioles. Ara- 

 l/is rhomboidea Pursh. Pers. 



HAB. Low grounds. From Hudson's Bay to S. Car. and W. to 

 the Rocky mountains. May, June. U.Stem 612 inches 

 high, erect, smooth, simple. Flowers in terminal racemes, large 

 white. 



2. C. rotundtfblia Midi. : root fibrous; leaves suborbicular, subdentate, 

 smooth, petioled ; stem weak, procumbent ; pod spreading, slender, 

 with a long style. 



HAB. Wet grounds. N. S. July. If. Stem 1215 inches 

 high. Flowers small, white. Dr. Hooker considers the two 

 preceding plants identical ; but Dr. Darlington, who has exami- 

 ned this point with much care, has designated the characters by 

 which they are distinguished. The roots of C. rotundifolia are 

 constantly fibrous, while those of C. rhomboidea are tuberous ; 

 the flowers of the former are not more than half the size of U- 



