COMPOSITAE (COMPOSITE FAMILY) 



539 



smooth, green, hollow between nodes, filled with milky juice. Leaves 

 lyrate-pinnatifid, the terminal lobe large and triangular, the others 

 narrow and decreasing in size toward 

 the base; the lower and basal leaves 

 petioled, but those on the stem clasping 

 with an auricled and pointed base ; the 

 margins toothed with small, weak 

 spines. Heads in crowded cymose 

 panicles, yellow, nearly an inch broad ; 

 the involucres are downy while they 

 enclose the buds, but later become 

 smooth. Achenes brown, slightly flat- 

 tened, with roughened ribs and thickly 

 tufted, white, silken pappus. (Fig. 

 372.) 



Means of control 



Prevent seed development. In gar- 

 dens and other small areas, hand-pull 

 before the first flowers mature. Stub- 

 bles should have surface cultivation 

 after harvest for the purpose of stirring 

 into life such seeds as are on the ground, A *' 

 the seedlings to be turned under at fall plowing. Waste places 

 and roadsides are too often permitted to mature seeds, to the 

 damage of adjacent ground. 



FIG. 372. Common Sow 

 Thistle (Sonchus oleraceus) . 



SPINY-LEAVED SOW THISTLE 

 Sdnchus dsper, Hill 



Introduced. Annual. Propagates by seeds. 

 Time of bloom : May to October. 

 Seed-time: June to November. 

 Range: All cultivated parts of the world. 

 Habitat: Fields, roadsides, waste places. 



More prickly than the preceding species ; the spines, though weak 

 compared with those of true thistles, can make themselves felt 

 when touched, while those of the Hare's Lettuce are too soft to pene- 



