CRUCIFERAE (MUSTARD FAMILY) 



71 



D. caroliniana. Whitlow Grass. Small, 2.5-12 cm. high; petals 

 usually twice the length of the calyx; pods broadly linear and smooth, 

 much longer than the ascending pedicels. Sandy and waste fields. 

 March to May. 



LEPIDIUM 



Small plants with simple leaves, small white or greenish flowers, 

 and a roundish pod much flattened in a direction opposite to the 

 narrow partition. 



L. virginicum. Wild Peppergrass. Leaves with tapering base, the 

 upper linear or lanceolate and entire, the lower incised or pinnatifid; 

 the orbicular or oval pods with a small notch at the top; stamens only 

 2. Common along roadsides. June to September. 



L. apetalum, Peppergrass. Pod orbicular and minutely wing- 

 margined at the top. Petals usually wanting. Dry places, especially 

 roadsides. 



CAPSELLA 



Low annual plants with clustered pinnatifid basal leaves, and 

 arrow-shaped sessile stem leaves. The raceme of small white 

 flowers continues to elongate 

 through the season. The pod is tri- 

 angular and flattened in a direction 

 opposite to that of the narrow par- 

 tition. Seeds numerous. 



C. Bursa-pastoris, Shepherd's 

 Purse. A very common weed, ex- 

 tremely variable in foliage and in out- 

 line of the pod, whose shape gives it 

 its common name. April to Sept. 



BRASSICA 



Annuals or biennials with yellow 

 flowers. The lower leaves are in- 

 cised or pinnatifid. 



B. arvensis, Charlock. A frequent and injurious weed in grain 

 fields. The knotty pods are fully one-third occupied by a stout 2-edged 

 beak. The upper leaves are scarcely petioled and are merely toothed 



Capsella Bursa-pastoris, Shepherd's 

 purse; a, flowers and fruit; b, 

 root leaf; c, stem leaf; d, clasping 

 upper leaf. 



