176 FARM WEEDS OF CANADA 



BLUE LETTUCE (Lactuca pulchella (Pursh) DC.) 



Other English names: Showy Lettuce, Large-flowered Blue 

 Lettuce. 



Other Latin names : Mulgediumpulchellum }^utt.; Mulgedium 

 acuminatum DC. ; Sonchus pulchellus Pursh. 



Native. Perennial, deep-rooted. Stems 2 to 3 feet, leafy 

 below. Whole plant smooth and covered with a fine bloom, 

 filled with milky juice. Leaves variable, linear-lance-shaped 

 or oblong; without teeth or divisions, or sometimes dentate 

 or pinnatifid, the divisions directed backward ; stem-leaves less 

 divided and stalkless. The flower heads are nearly 1 inch 

 across, pale blue, not very numerous, on scaly footstalks, in a 

 narrow panicle. 



The seed (Plate 76, fig. 99) i3 about 1/4 inch long, including 

 the short, thick beak, the tip of which is whitish, expanded 

 into a short, cup-shaped disc, red when immature, slaty-gray 

 when ripe; club-shaped, flattened with thick ridges down each 

 face; whole surface dull and rough; pappus longer than the seed, 

 pure white and silky. 



Time of flowering : June-July ; seed ripe by about the end of 

 July. 



Propagation: By seeds and fleshy, deep, persistent, running 

 rootstocks. 



Occurrence: Throughout the Prairie Provinces and British 

 Columbia; in moist or sandy soil, particularly where there is some 

 alkali. 



Injury: A deep-rooted, troublesome weed, having all the 

 bad characteristics of Prickly Lettuce and much more difficult 

 to suppress. 



