462 COMPOSITAE (COMPOSITE FAMILY) 



pair of strong, hooked beaks at the tip and a covering of hooked 

 spines which enable them to cling to a garment or to the coats of 

 animals for a ride to new homes. Each bur contains two "seeds," 

 or achenes, oblong, flat, slightly ridged, with a tough, black coat, 

 or skin. It is believed that one 

 of the pair germinates the first 

 season and the other the next, 

 thus assuring a two-years' crop for 

 one sowing. But the entire bur 

 is also known to lie dormant in 

 the soil for several years. Sev- 

 eral other species of Clotbur are 

 common and all are about as 

 obnoxious as this one but none 

 ranges so widely as X. canadense. 

 (Fig. 322.) 



Means of control 



Hoe-cutting while the plants are 

 small ; or, if not too numerous, 

 FIG. 322. Clotbur (Xanthium hand-pulling before the burs are 

 canadense). x J. formed. Put infested corn land to 



a grain crop, followed by clover or grass, the harvesting of any 

 of which beheads the weed before it has attained to much size or 

 developed the burs. In its tender youth (three to eight inches in 

 height) Clotbur can be killed by a spray of Iron sulfate or Copper 

 sulfate. Plants on waste land or roadside which have been 

 allowed to mature their burs should be cut and burned. 



BLACK-EYED SUSAN 

 Rudbeckia hirta, L. 



Other English names: Yellow Daisy, Golden Jerusalem, Darkey- 

 head, Nigger-head, Ox-eye Daisy. 



Native. Biennial. Propagates by seed. 



Time of bloom : June to October. 



Seed-lime: July to November. 



Range: United States and Canadian Provinces east of the Rocky 

 Mountains. 



Habitat : Prairies ; meadows and pastures, waste places. 



