DESCRIPTIONS OF SOME COMMON WEEDS 165 



tario and Manitoba, extending south to Tennessee and 

 Arkansas, and west to the Great Basin in Utah. 



Another ally of these is the bushy knotweed (P. 

 ramossissimum), an annual with bright or yellowish 

 green, smooth leaves, erect o.r ascending stem, generally 

 branched, from two to three feet high ; flowers several in 

 axillary clusters, greenish, pedicellate, achenes exserted, 

 shining, three-angled, reticulate, dull in color. Common 

 in Manitoba, Dakotas, Maine and New Jersey to Mis- 

 souri, New Mexico and California, f 



Muhlenberg's Smartweed or Marsh Smartweed (Poly- 

 gonum Muhlenbergii (Meisn.) Watson). A decumbent 



or nearly erect perennial, 

 with long underground 

 rootstocks ; grows from one 

 to three feet tall; flowers 

 bright rose color, arranged 

 in spikes from one to three 

 inches long. Extremely com- 

 mon in low grounds, espe- 

 cially in old lake beds and 

 ponds, which, when drained 

 and planted with corn, 

 often grow up to this weed, 

 in the North. 



Lady's Thumb (Polygo- 

 num Per sic aria, L.). A 

 nearly smooth annual or 

 Fig. 98.. Dooryard weed (Poly- biennial from twelve to 

 gonum awculare). . 1 . . , . , 



eighteen inches high ; 



leaves lanceolate, pointed and somewhat rough, often 

 marked with a dark triangular spot near the middle; 

 spikes differ from those on P. pennsylvanicum, in being 

 on peduncles that are free from glands; spikes ovoid or 

 oblong, dense, and erect; calyx colored; stamens gener- 

 ally six; styles two to three-cleft; achene smooth and 



