DICOTYLEDONS. 89 



Pod many times longer than broad. 



Flowers yellow V. Sophia. 



Flowers white or colored. 



Seeds globose VII. Hesperis. 



Seeds flat III. Cardamine. 



Pod short. 



Flat, orbicular. 



Flattened contrary to the partition . I. Lepidium. 



Flattened parallel to the partition . . VI. Koniga. 



Flat, cuneiform IV. Bursa. 



Terete, globose or oblong .... II. Roripa. 



I. LEPIDIUM. 



Annual ; stem erect, or sometimes diffuse ; leaves entire, 

 toothed or pinnately divided ; flowers in a terminal raceme, 

 small, white ; petals short, sometimes wanting ; stamens 2, 

 4, or 6; silicle rounded or obcordate, flattened contrary to 

 the partition. 



L. ViRGixicuM L. Pkitergrass. Stem erect, smootli, much 

 branched, 1-2 ft. high; lower leaves ohovate in outline, pinnatifid 

 with dentate lol)es; upper leaves lanceolate, dentate, slightly pubes- 

 cent ; flowers on slender pedicels, petals often wanting in the later 

 ones ; stamens 2 ; silicle orbicular. JMarch-July. A weed growing 

 in waste places. 



II. RORIPA. 



Annual or biennial ; stems erect or diffuse, often widely 

 branching ; leaves simple, pinnately lobed ; flowers small, 

 wliite or yellow; sepals spreading; stamens 1-6; silique 

 short and broad or nearly linear ; seeds numerous, in 2 rows 

 in each cell. 



1. R. XASTi'KTirM (L.) Ru.sby. \Vateucrp:ss. Aquatic heriis; 

 stems glahrous, diffuse, rooting at tlie joints; leaves with '')-.) 

 rounded, pinnate lobes, the terminal lobe mucli the largest; racemes 

 elongating in fruit; petals white, twice the length of the sepals; 

 l>()d linear, i-ij in. long, on slender, sjjreading pedicels. Mareh- 

 Xovember. In <litches and slow streams. Often used for salad. 



2. R. I'Ai.rsTRis (L.) Bess. Yi.i.iow Watkkcrkss. .Annual 

 or biennial; stem erect, branched, slightly pubescent; leaves irregu- 



