POL YGONACE.E— BUCKWHEAT 

 FAMILY 



PINK KNOTWEED. SMARTWEED 



Polygonum Pennsylvdnicum 



One of our native common weeds which bears pink 

 spikes above leafy stems; in moist ground, by the road- 

 side or over the fence, on rubbish heaps and in waste 

 places, from midsummer to frost. Nova Scotia to the 

 Gulf of Mexico, west to Minnesota and Texas. July- 

 October. 



Stems. — Erect, one to three feet high, smooth, simple 

 or branched, often reddish, the joints swollen and sheathed. 

 The sheaths are united stipules called ocrea3. The upper 

 branches and peduncles often glandular. 



Leaves. — Lanceolate or long-oval, two to ten inches 

 long, ciliate, acute or acuminateat apex; petiole short. 



Ocrece cylindric, naked; glabrous. 



Flowers. — Small, pink, borne in dense, terminal, obtuse 

 spikes, one to three inches long. 



Calyx. — Small, pink or greenish, five-parted. 



Corolla. — Wanting. 



Stamens. — Eight or ten. 



Pistil. — Ovary one; style two-parted. 



Fruit. — A shining, circular, flattened seed within the 

 protecting calyx. 



This Polygonum grows in colonies whenever it can 

 and is the plant chiefly responsible for the masses of 

 pale-pink flowers in low meadows and neglected fields 



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