104 POLYGONACEAE (BUCKWHEAT FAMILY) 



Means of control 



Prevent seed development. Even so expensive a process as 

 hand-pulling is often worth the labor if it hinders so pernicious a 

 weed as this from fouling the ground with its long-lived seeds. In 

 grasslands and grain fields a spray of four-per-cent solution of 

 Copper sulfate will greatly damage the foliage of the weed, checking 

 growth and usually blasting the budding flowers. In cultivated 

 ground it is readily subdued by the necessary tillage. 



BLACK BINDWEED 

 Polygonum Convdlvulus, L. 



Other English names: Wild Buckwheat, Knot Bindweed. 

 Introduced. Annual. Propagates by seeds. 



Time of bloom: June to September. 

 Seed-time: July until cut off by frost. 

 Range: Throughout North America ex- 

 cept the extreme North. 

 Habitat : Fields and waste places ; invades 

 most crops. 



Not very troublesome in ground re- 

 quiring close tillage, but a special nuisance 

 ingrain fields ; climbing over and strangling 

 the rightful growth, robbing it of food 

 and moisture, bending it down by weight 

 of its own fruitage. The seeds have long 

 vitality and begin to ripen and drop into 

 the soil before harvest ; are gathered with 

 the grain and often distributed with it ; 

 often fed to cattle in screenings from the 

 mills, and returned to the soil in stable 

 refuse or in droppings. 



Stem slightly angular, roughish, branch- 

 ing, one to three feet long. Leaves 

 halberd-shaped or long-pointed, heart- 

 shaped, smooth, dark green, with slender 

 petioles usually not so long as the blades. 

 Flowers in slim, interrupted, axillary ra- 



volvulus). X \. 



