DESCRIPTIVE MANUAL 235 



Spreading Dogbane (Apocynum androsaemifolium L.). 



Description. — Root-stock horizontal, smooth, or rarely soft-tomen- 

 tose, branched above, spreading, leaves ovate, petioled, cymes loose, 

 spreading, both terminal and axillary; the latter pale rose color, 

 open, bell-shaped; calyx segments shorter than the tubes of the 

 corolla. 



Distribution. — Common along borders of thickets from eastern 

 Canada to British Columbia to Arizona and Georgia. Abundant 

 in Iowa in grain fields near thickets. 



Fig. 135. Distribution of Spreading Dogbane {Apocynum androsaemifolium). 



Extermination. — Spreading dogbane produces long, creeping 

 roots, which are quite tenacious of life. In order to destroy the 

 weed, the field should be given a shallow plowing after the grain is 

 harvested, followed by a disking in a week or ten days, depending 

 on the character of the weather. This should be followed by a 

 harrow. If the fall is dry dragging will probably get the larger 

 number of these weeds. 



Indian Hemp (Apocynum cannabinum L.). 



Description. — Glabrous or more or less softly pubescent; 2-3 ft. 

 high, smooth, terminated by an erect, close, many-flowered cyme; 

 corolla lobes nearly erect, the tube not longer than the lanceolate 

 segments of the calyx, greenish white ; appears in July and August. 



Distribution. — Common species eastward and troublesome as a 

 weed in northern Mississippi valley. Common in small-grain fields 

 and pastures. 



