Pol^gonumJ] LXXII. POLYGONACEiK. 



363 



We Iiave seen foreign specimens (from Hamburgh) precisely inter- 

 mediate between this and the next. 



2. S. perennis L. (perennial K.) ; calyx of the fruit witli 

 obtuse closed segments edged with a broad white membrane, 

 stems procumbent, root perennial, i?. JB, t. 352. 



Open dry sandy fields, in Norfolk and Suffolk. 1/.. 8 — 10. — 

 Stems simple or irregularly branched, glaucous. The broad white 

 membrane gives the flowers a variegated appearance. 



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Ord. LXXII. POLYGONACEiE Juss. 



Sometimes monoecious or dioecious. Perianth free, divided, 

 the segments often in a double row. Stamens definite, but 

 varying In number, inserted into the base of the perianth. Ovary 

 superior, with 2 or more styles or sessile stigmas, Achene fre- 

 quently 3-angular or lenticular, with one erect seed. Embryo 



in a farinaceous albumen^ often lateral, 

 shrubby plants, with sheathing stipules! 



Herbaceous, rarely 

 The stems and leaves 



are acid and astringent ; the roots, in general, nauseous and 

 purgative ; while the seeds are very farinaceous and esculent. 

 The True Rhubarb belongs to this Order: it is a species of 

 Wieum not clearly ascertained. 



1. Polygonum, Perianth 5-partite. Styles 2 — 3. Achene wingless, 



compressed or triquetrous. 



2. RuMEX. Perianth 6-partite; the three inner segments at length larger, 



connivent, and covering the triquetrous wingless achene. Styles 3, 



3. OxYKiA. Perianth 4-partite : the two inner segments larger. Styles 



2. Achene compressed, with a membranous wing, at length 

 larger than the perianth, 



1. Polygonum Linn. Persicaria, Bistort, Knot-grass, and 



Buck-wheat. 



Perianth single, in 5 deep, coloured, persistent segments. 

 Stam. 5 — 8. Styles 2 — 3. Achene compressed or trigonous. 

 Named from ttoXvq^ many^ and yovv^ a knee or joint ; from the 

 numerous joints of the stem. 



Styles 3, ajid the fruit triquetrous. Stem simple, with one terminal 

 spiked raceme. Stipules truncated. Root thick and short. Bistort. 



!• P.^ Bistorta L. (common B. or Snakeweed) ; raceme dense 

 cylindrical, leaves subcordate-ovate waved, the radical ones 

 with a winged foot-stalk. E. B. t. 509. 



Moist meadows in various parts of England, Scotland, and Ireland, 

 ^. 6 — 9. — Stem 1 — l^ foot high. Upper haves with long sheaths. 

 Flowers flesh-coloured, ou short foot-stalks, with small hracteas at 

 their base. Stam. 8. Styles 3. Root large, tortuose, very astrin- 



gent. 



R 2 





