62 



FIG. 26. 



YELLOW DAISY, CONE-FLOWER, BLACK-EYED SUSAN, OR NIGGERHEAD. 



Rudbeckia hirta (L). 



A biennial and sometimes annual weed found in pastures and mead- 

 ows. It grows about 1 to 3 feet high. The stems are sparingly branched 

 and very bristly. The leaves are thick, hairy, oblong and tapering to- 

 wards the point. The flower is about 1 in. across, with orange yellow 

 rays or petals (10 to 20 in number) and dark purple brown discs almost 

 spherical or cone-shaped. The seeds are dark brown, almost black, four- 

 angled, and aboub J in. long, with no pappus, or tuft of hair (Fig. 26, a). 

 An average plant produces about 2,000 seeds. 



Time of flowering, June-August 



Time of seeding, July-September. 



Dispersal as an impurity in seed grain. 



Eradication. It can generally be killed by mowing, but it is some- 

 times necessary to break up meadow or pasture land, as suggested in note 

 to Mr. Rennie's method of cleaning land (see page 8), and follow with a 

 hoed crop. If this is well cared for, it will destroy all Cone-flower. 



