DIPSACACEAE (TEASEL FAMILY) 403 
eat these weeds readily, but they are less nutritious than grasses 
and do not make good hay. The seeds are said to retain their 
vitality for about five years when buried in the soil. 
Means of control 
Prevent production of seed by early and frequent cutting. 
Where practicable, put the ground under cultivation for a season 
in order to stir dormant seeds into life and destroy them with the 
needed tillage. 
TEASEL . 
Dipsacus sylvéstris, Huds. 
Other English names: Card Thistle, Water 
Thistle, Gipsy Combs. 
Introduced. Biennial. Propagates by 
seeds. 
Time of bloom: July.to September. 
Seed-time: August to October. 
Range: Maine and Ontario to Virginia, 
westward to Michigan. 
Habitat: Pastures, roadsides, fence rows, 
and waste places. 
Stems stout, erect, strongly ridged, 
branching, beset with spines, three to six 
feet tall, springing from a stout taproot 
often more than a foot long with many 
feeding rootlets. Root-leaves of the pre- 
vious year’s growth tufted in a broad and 
very flat rosette, oblong to lance-shaped, 
obtuse, tapering at the base, scallop- 
toothed, the surface wrinkled and deep Sa eee 
green except the veins and midrib, which (pjipsacus sylvestris). Xt. 
are nearly white and beset with spines; 
stem-leaves opposite and often united at the base, forming cups 
which retain water, the rigid midribs spiny on the under side. 
Flowers in large, dense, solitary heads, sometimes nearly four inches 
long and two inches in thickness, protected by long, upcurving, 
spiny involucral bracts and lifted on long, spiny peduncles, terminal 
and axillary; corollas lilac or pinkish purple, tubular, four-lobed, 
