WEEDS OF THE BUCKWHEAT FAMILY. 



65 



Occurs in the same places as 

 the curled dock, but less common. 

 June- Aug. The seeds of both these 

 docks are often found in clover and 

 alfalfa seed which has not been 

 properly cleaned. Where found in 

 cultivated land, both can be eradi- 

 cated only by short rotation or thor- 

 ough cultivation with hoed crops. 



19. POLYGONUM PENNSYLVANICUM L. 



Pennsylvania Smart weed. Gland- 

 ular Persicary. (A. N. 2.) 

 Erect, simple or branched, 2-l> feet 

 high, the flower stems with numerous 

 glands; leaves lanceolate, pointed, 2-11 

 inches long. Spikes several, short, erect, 

 cylindrical, dense flowered ; calyx dark 

 pink or rose color, 5-parted. Seeds lens- 

 shaped, inch long, dark, shining. 



Fig. 31. ( After Vasey 



(Fig. 32.) 



Common in moist soil, 

 especially that near the 

 margins of lakes, ponds 

 and marshes. July-Oct. 

 Stems stouter than our 

 other forms and when old 

 very hard and woody. 

 Seeds frequent in those of 

 clover cut from lowlands. 

 The leaves are often spot- 

 ted with a reddish leaf- 

 spot fungus and the heads 

 are sometimes affected with, 

 a smut which destroys the 

 s(H j ds. Remedies: mowing 

 before the seeds have rip- 

 ened; hoeing, pulling and 

 cultivating. 



20. POLYGONUM PERSICARIA L. 

 Lady's Thumb. Spot- 

 ted Smartweed. Heart- 

 weed. (A. I. 2.) 

 Stem erect or ascendirg, simple or much branched, glabrous, (5 inche. 



to 2 feet high; leaves lanceolate, pointed at both ends, often with a tri- 



Fig. 32. Showing the flower opened and spread apart and 

 the fruit with its two styles. (After Small.) 



[5] 



