CRUCIFERAE (MUSTARD FAMILY) 179 
Means of control 
Infested grain fields and meadows should be sprayed with Iron 
sulfate or Copper sulfate before the first flowers mature. Stubbles 
should be cultivated after harvest in order to destroy autumn 
seedlings. 
SWINE CRESS 
Corénopus didymus, Sm... 
(Senebiera didyma, Pers.) 
Other English names: Lesser Wart Cress, Carpet Cress. 
Introduced. Annual or biennial. Propagates by seeds. 
Time of bloom: March to June. 
Seed-time: Early May to August. 
Hanae: Newfoundland to Florida and Texas, westward to Cali- 
ornia. 
Habitat: Yards, roadsides, waste places. 
Grazing cattle usually avoid plants with a disagreeable odor, but 
they seem to make an exception of the Mustards. The smell of 
this weed is suggestive of a pigsty, 
whence its name of Swine Cress; it 
is occasionally the cause of damaged 
dairy products. (Fig. 123.) 
Stems four inches to a foot in 
length, prostrate, diffusely branched, 
hairy, spreading on all sides from 
the root. Leaves very deeply pin- 
natifid, some but once, others with 
the segments also cut; upper ones 
sessile but those near the base having 
slender petioles. Flowers white, ex- 
tremely small, in slender axillary 
racemes on short, threadlike pedicels. 
Autumn plants flower earliest, com- 
ing into bloom as soon as uncovered 
from winter snows. Silicles small, wrinkled, warty, the two 
valves separating readily into two ovoid nutlets, each con- 
taining one seed. 
Fia. 123. — Swine Cress (Corono- 
pus didymus). X }. 
