3^8 



WEED FLORA OF IOWA 



Fig. 215-A. Distribution of Biennial Wormwood. 



lower leaves twice pinnately parted, the upper pinnatifid, the 

 lobes linear or linear-oblong, serrate or cut-toothed; inconspicuous 

 flowers; ray flowers absent; heads numerous in short axiUary 

 spikes; bracts of involucre green, scarious, margined. 



Distribution. — Common in the northern Mississippi valley; now 

 widely scattered east to Nova Scotia and south to Kentucky. It 

 occurs in many parts of the state of Iowa. 



Extermination. — ^Readily succumbs to cultivation. The plant 

 should be cut off close to the surface of the ground. 



Fireweed {Erechtites Meracifolia L. Raf.). 



Description. — ^A coarse, annual weed of rank odor and grooved, 

 often hairy stem; leaves simple, lanceolate or oblong, acute, eut- 

 topthed, the upper with aUricled base; heads many-flowered; re- 

 ceptacle naked; flowers tubular and perfect; achenes oblong, tap- 

 ering; soft, white, capillary bristles. 



Distribution. — This weed is common in moist woods; in the 

 north especially in recent clearings which have been burned over, 

 hence the common name fireweed; also occurs in the Rockies, and 

 Kansas; common in many parts of Iowa, especially along streams. 



Extemvmation. — Easily exterminated by cultivation, 

 should b« cut off close to the surface of the ground. 



Plants 



