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KNOT-GRASS. POLYGONUM. 

 (PERSICARIA. BUCK WHEAT.) 



The plants of this genus vary much in the number of the stamens; 

 sometimes there are only five, at other times six, eight or ten. Ihe styles 

 also vary from one to three, when one only it is always forked. 



* Styles three. Stamens eight or ten. Fruit three-cornered. 



COMMON KNOT-GRASS. Polygonum aviculare. 



Plate 5, fig. 4. 

 Stem prostrate. Leaves ovate, blunt. Flowers axillary. 



A small, prostrate, wiry, much-branched plant, neither ele- 

 gant nor useful, growing abundantly on every waste ground, 

 and flowering all the latter part of the summer. Every joint 

 of the stem is furnished with short sheath-like stipules, out of 

 which grow both the leaves and flowers. The leaves are without 

 stalks, of a blunt ovate form. The flowers are red, small, 

 three or four to each leaf, and very nearly sessile. 



CLIMBING BUCK WHEAT. Polygonum convolvulus. 



Plate 5, fig. 5. 



Stem climbing. Leaves arrow-shaped. Flowers in spikes. 

 The long climbing stem, growing as it does among the hedges 

 to the length of three or four feet, and the arrow-shaped stalked 

 leaves with which it is beset, at once distinguish the Climbing 

 Buck Wheat. Added to which, the manner of bearing its little 

 whitish -green flowers in very loose alternate leafy spikes is 

 another mark of distinction. 



** Styles one or two. Stamens five or six. Fruit two-edged. 



AMPHIBIOUS PERSICARIA. Polygonum amphilium. 



Plate 5, fig. 6. 

 Stamens five. Style one, forked. Spike ovate. 



A perennial plant, spreading widely over the surface of rivers 

 and ponds, where its rose-colored, large, ovate, thick, and up- 

 right spike of flowers, looks very handsome. The leaves are 

 lanceolate, stalked, serrated, sometimes smooth, at others hairy, 

 and generally lying upon or under the water, The roots are 

 fibrous and surround almost all of the lower joints, while the 



