130 FARM WEEDS OF CANADA 



HEMP NETTLE (Galeopsis Tetrahit L.) 



Other English names: Hemp Dead Nettle, Bee, Dog, Blind 

 or Stinging Nettle, Nettle-wild or Bastard Hemp. 



Introduced from Europe. Annual. Stem erect, tall, swollen 

 below the joints, rough hairy. Leaves ovate, with strong, 

 forward-pointing teeth, tapering at the end, on slender foot- 

 stalks. Flowers purplish, white or variegated, grouped into 

 nearly stalkless clusters at the axils of the leaves; corolla dilated 

 at the throat, about twice as long as the calyx; the teeth of the 

 latter needle-pointed, bristly. 



The seed (Plate 75, fig. 65) closely resembles that of cul- 

 tivated hemp, though smaller, about 1/8 inch long. It is broadly 

 egg-shaped in outline, one surface rounded, the other bluntly 

 keeled from the round, fiat, depressed scar up to the middle. 

 The whole seed is grayish brown, wrinkled from unevenly scat- 

 tered, whitish tubercles. 



Time of flowering: July to September; seed ripe in Sep- 

 tember. 



Propagation : By seeds. 



Occurrence: A common weed around barns and in rich, 

 damp soil in grain fields in all settled parts of Canada. 



Injury : This coarse-growing plant occupies much space 

 and crowds out crops. 



Remedy: Hand-pull whenever practicable. Sow clean 

 seed and prevent plants from seeding. Close cutting for a few 

 years will suppress it in waste places, which should be seeded 

 to permanent grass. Thorough cultivation with short rotation 

 of crops will eradicate it. 



ALLIED SPECIES: Catnip (Nepeta Cataria L.), an intro- 

 duced perennial, the seeds of which (Plate 75, fig. 62) are often 

 found in clover seed. They are about 1/16 of an inch long. 



