166 i^ARM WEEDS OF CANADA 



large, nearly 2 inches across, solitary at the end of the branches. 

 The seed is also similar to that of Canada Thistle, but broader, 

 more flattened, about 1/3 of an inch long, highly shiny. This 

 is not a serious pest and soon disappears when the land is put 

 under crop. 



Closely allied to these thistles are the Knapweeds (Centaurea).- 

 Common Knapweed (Centaurea nigra L.), is rather abundant in 

 meadows in the Maritime Provinces. It is a coarse perennial with 

 thistle-like flowers, over 1 inch across and 1^ inches high. The 

 calyx-like whorl of bracts surrounding the flower heads is 

 spherical and composed of black-fringed scales. 



The seed (Plate 76, fig. 90) is about 1/8 inch long, half as wide, 

 tapering to the base, slightly angular, somewhat flattened and 

 the dark, shining gray surface striped lengthwise with pale 

 ridges; the whole seed is sparsely hairy. The large apical scar 

 covers the whole of the top and is surrounded by a pappus of 

 2 or 3 rows of short, flat bristles. A characteristic of this seed, 

 is the more or less hooked pointed end bearing the basal scar. 



TRIBE CICHORIEAE 

 CHICORY (Cichorium Intybus L.) 



Other English names: Wild Chicory, Wild Succory, Blue 

 Sailors. 



Introduced from Europe. Perennial from a deep, long, 

 thick root. Stems 2 to 3 feet high, branched, hairy below. Root- 

 leaves closely resembling those of Common Dandelion, 6 to 8 inches 

 long, spreading on the ground, dentate or pinnatifid with 

 the divisions directed backward; midribs hairy beneath; upper 

 leaves glandular hairy on the margins, clasping at base. 

 Flower heads bright blue, sometimes purple or nearly white, 

 about 2 inches across, composed entirely of strap-shaped flowers, 

 usually closing by noon, in stalkless clusters of 3 or 4 together 

 along the almost leafless stems. 



The seed (Plate 76, fig. 91) is 1/8 inch long, dark brown or 

 straw-coloured, mottled with brown, wedge-shaped, obtusely 



