CLASS VIII. ORDER III. X65 



marked with purple. Anthers scarlet before opening. Nectary 

 a dark, purplish, elevated ring, growing to the corolla, and sur- 

 rounding the two conical germs. The terminal flower is often 

 decandrous. Considered by Sir W. J. Hooker as a distinct spe- 

 cies from the European, from its different size and habit, and 

 from its flowers not being corymbed. — Wet places. — April, May. 

 — Perennial. 



TRIGYNIA. 



179. POLYGONUM. 

 Polygonum aviculare. L. Knot Grass. 



Stem proctimbent, herbaceous; leaves lance-oval; 

 flowers axillary, subsessile, with eight stamens and 

 three styles. 



A hardy weed growing every where, and even common among 

 the bricks and paving stones. Stem slender, spreading, striated, 

 interrupted with frequent joints, branching; the joints furnished 

 with short stipules. Leaves oblong-oval, smooth. Flowers 

 minute, white, in the axils of the leaves.^AU summer. — Pe- 

 rennial. 

 Polygonum tenue. Mx. Slender Polygonum. 



Leaves linear, straight, acuminate; sheaths tubu- 

 lar, villous at top; stem slender, erect, branched, 

 acute angled; flowers alternate, subsolitary. 

 Syn. Polygonum linifolium. Miihl. 



A small erect species with scattered, axillary, nearly sessile 

 flowers. — Dry soils.— July. — Annual. 

 Polygonum hydropiper. L. Water Pepper, 



Stamens from six to eight; styles two, half united ; 

 leaves lanceolate, spotless, waved ; spike filiform, 

 nodding; stem erect. 

 Syn. Polygonum hydropiperoides. Pursh. 

 Polygonum punctatum. Ell. 



Well known for its intense acrimony. Leaves lanceolate, 



