DESCRIPTIONS OF SOME COMMON WEEDS 239 



toothed; lower leaves abruptly contracted into a long, 

 slender petiole; involucral bracts lanceolate or oblong- 

 lanceolate, with acute or mucronate tips ; flowers one-half 

 inch or more in diameter. Especially distinguished from 

 two preceding species by character of petiole and the fact 

 that the head is smaller. Found in various parts of Iowa ; 

 naturalized in eastern parts 

 of state, especially on Mus- 

 catine Island, whither it was 

 probably carried in stock 

 cars. 



Meadow Sunflower (Heli 

 anthus grosseserratus, Mar 

 tens). A tall, smooth pe- 

 rennial six to ten feet high, 

 bearing numerous leaves, 

 short oblong-lanceolate, acu- 

 minate with sharp teeth, 

 the upper sometimes merely 

 denticulate, rough above, 

 whitish below; lower stem 

 leaves eight to ten inches 

 long, petiole one to two 

 inches long; heads one-half 

 inch long with deep yellow Fig. 151. Common sunflower 

 rays about an inch long; (Helianthus annuus). 

 bracts of involucre slender. 



Common throughout the state, and while at times 

 troublesome in corn fields, especially on low grounds, it 

 usually occurs in swales where there is considerable moisture. 



Maximilian's Sunflower (Helianthus Maximiliani, 

 Schrad.) This plant resembles meadow sunflower; it is 

 stout, often with simple leaves, rigid and scabrous. Heads 

 rather large. Common from Minnesota to Texas. 



Beggar-ticks, Stick-tights (Bidens frondosa, L.). A 

 branching, hairy, or smooth annual, two to six feet high ; 



