70 



WEED FLORA OF IOWA 



Fig. 3 8- a. Distribution of Nettle. 



Distribution. — Eastern Canada to Wisconsin, Minnesota, central 

 Canada and Louisiana; found along roadsides, borders of thickets 

 and woods ; occasionally in gardens and waste places especially in 

 eastern and southern Iowa. 



Extermination. — The perennial root stocks make this weed quite 

 persistent and difficult to destroy, because the weed often occurs in 

 inaccessible places along fence-rows ; howevei-, persistent cultivation 

 will exterminate the weed. 



Chemical Composition.* 



I'RESH OB AIB DR^ tATEEIAL. 



Hemp (Cannabis sativa L.). 



Description. — A rough, stout, dioecious annual, 3-10 ft. tall; 

 inner bark of tough fibers ; leave's digitate, of 5-7 linear-lanceolate, 

 coarsely toothed leaflets, the upper alternate; flowers green; stam- 

 inate, in compound racemes; pistillate, in erect spikes, each con- 

 sisting of a calyx of a single sepal folded around the ovary and 2 

 filiform stigmas ; fruit an achene ; endosperm fleshy ; embryo 

 curved. 



♦Compiled by Jenkins and Winton: Bull. Off. Exp. Sta. 11. 



