DIPSAC'ACEAE (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 sylvestris, 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 

 green except the veins and midrib, which (^Xpwew s^hestris). C ?|. 

 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, 



