WEEDS OF TPIE BICKWHEAT FAMILY. 



65 



Fig. 31. (After Yasey— 



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 

 seeds. 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.) 

 st.'in erect or ascendii g. sini 



to 2 feet high; loaves lanceolate 



Occurs in tin 1 same places as 

 the curled dock, hut 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 he eradi- 

 cated only by short rotation or thor- 

 ough cultivation with hoed crops. 



19. Polygonum pennsylvanictjm L. 



Pennsylvania Suiartweed. Gland- 

 ular Persicary. (A. N. 2.) 

 Erect, simple or branched, 2-6 feet 

 high, the flower stems with numerous 

 glands ; leaves lanceolate, pointed, 2-1 1 

 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. 32.) 



Fig. ;52. Showing the flower opened and spread apart and 



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



pie or much branched, glabrous, 6 inche. 

 , pointed at both ends, often with a tri 



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