THE SUNFLOWER FAMILY 173 



Occurrence : Widely distributed throughout eastern Canada 

 and westward to the Prairie Provinces, in fields, gardens and 

 waste places. 



Injury: A troublesome weed in cultivated lands. Because 

 of its natural means of distribution, it is difficult to suppress. 



Remedy : Prevent it from seeding in waste places by cleaning 

 them up and seeding them to permanent, vigorous grasses. 

 This annual weed, with its relatively small, pale yellow flowers, 

 when compared with the perennial species is not difficult to control 

 by ordinary methods of cultivation and alternation of crops. 

 Sheep, if in sufficient numbers, will prevent sow thistles from 

 seeding in pasture lands. 



ALLIED SPECIES: Spiny-leaved or Prickly Sow Thistle 



(Sonchus asper (L.) Hill.) is an annual of the same habit as Com- 

 mon Sow Thistle. It may be easily identified by its more prickly 

 nature and less deeply cut leaves, the base appendages of 

 which, instead of spreading, are appressed to the stem and 

 rounded. 



The seed (Plate 76, fig. 96) is similar to that of the preceding 

 species in size and shape; distinctly 3-nerved on each side, 

 with nerves and interspaces quite smooth. Pappus not persistent. 



Uncultivated lands, that are often a breeding ground for 

 sow thistles and other weeds, could be made less dangerous by 

 seeding to some vigorous, permanent grass that is able to main- 

 tain full possession of the soil. 



The thistle proves a great annoyance to some lands by killing the grass corn, etc., 

 although it be a sure token of the strength of the land. The way to destroy them is 

 to cut them up by the roots before feeding time; the advantage you will receive will ans- 

 wer your expense and more. 



John Worlidge, The Mystery of Husbandry Discovered and laid open, 1681. 



