BUCKWHEAT FAMILY. Polygonaceae. 



Knotgrass 



Polygonuvi 

 aviculare 

 Greenish 

 yellow 

 June- 

 September 



sheaths. 



Erect Knot= 

 weed 



Polygonum 



erectum 



Greenish 



yellow 



July 



September 



Pennsylvania 

 Persicaria 



Polygonum 



Pennsylvanicum 



Pink or white= 



green 



July 



September 



A slender species with a weak stem, 

 bluish green, small lance-shaped leaves, 

 scaly joints, and greenish pink-tipped 

 flowers. Common everywhere in culti- 

 vated and waste ground. The blue-green 

 leaves, alternate, or are in appearance 

 clustered, and issue from tiny brown 



A stouter and a j^ellowish green stem, 

 leafy ; the leaves nearly oval, and the 

 flowers greenish yellow. A common way- 

 side weed north of Tenn. and Ark., east 

 and west. The stem of this species is 

 noticeabl}^ erect with no tendencj'" to 

 sprawl. 



A somewhat.red-jointed species, at home 

 in wet waste places, with shiny lance- 



shaped leaves, and pink or white-green 

 flower-clusters; the upper branching stems 

 and flower-stems beset with tiny hairlike 

 glands. Common everywhere. It has a 

 branching, sprawling habit. 



A smooth-stemmed species, from the old 

 world, with similar leaves and crimson- 

 pink or deep magenta flowers, the leaves 

 rough and generally marked with a darker 

 green triangle in the middle. Very com- 

 mon in waste damp places. 



A common weed in all wet waste places, 

 indigenous in the far northwest, but 

 naturalized from Europe in the east. 

 Leaves narrow lance-shaped, very acrid 

 and pungent, and fringed with tiny 

 bristles. Flowers mostly green in a slim 

 long cluster, nodding. An annual 1-2 feet 

 liigh. The indigenous species P. hydropiperoides *vrith. 

 an equally wide distribution has pink or flesh-colored or 

 greenish flowers, branching stems, and very narrow 

 leaves, not acrid. Common south, and reported in Neb. 

 (Webber). 



Lady's Thumb 



Polygon um 

 Persicaria 

 Crlmson=pink 

 June- 

 September 



Smartweed 

 Water Pepper 



Polygonum 

 Hydropijjer 

 Green 

 July- 

 September 



io6 



