188 OCTANDRIA TRIGYNIA. [cL. VIII. 



TRIGYNIA. 

 10. POLY'GONUM. BUCE-WHEAT. 



Calyx inferior, turbinate, coloured, deeply divided into five 

 egg-shaped permanent segments. Corolla none. Filaments 

 variable in number, awl-shaped, very short ; anthers roundish. 

 Germen superior, roundish, triangular, or compressed. Styles 

 generally three, in some species two, thread-shaped, very short ; 

 stigmas simple. Seed solitary, triangular, or compressed, pointed. 

 Named from polys, many, and gonu, a knee or joint. 216. 



1. P. Bistdrta. Great Bistort. Snake-weed. Stem simple, bearing 

 a single spike ; leaves egg-shaped, waved, running down into the foot- 

 stalks. Stems erect, about two feet high, leafy : flowers rose-coloured. 



Perennial: flowers in June : grows in pastures and meadows: frequent. 

 Eng. Bot. vol. viii. pi. 509. Eng. Fl. vol. ii. p. 236. 607. 



2. P. viviparum. Alpine Bistort. Stem simple, bearing a single spike ; 



leaves lance-shaped, revolute at the margin. Stem from three to eight 



inches high, erect, leafy : flowers pale-red. Perennial : flowers in June 

 and July : grows in mountain pastures : frequent. Eng. Bot. vol. x. 

 pi. 669. Eng. Fl. vol. ii. p. 237. 608. 



3. P. aviculdre. Common Knot-grass. Flowers axillar ; leaves lance- 

 shaped, rough-edged ; stem procumbent. Stems several, decumbent, 



spreading in all directions: leaves alternate, stalked: flowers two or 

 three together, reddish. Annual : flowers in summer and autumn : 

 grows in fields, waste places, by roads, &c. : common. Eng. Bot. 

 vol. xviii. pi. 1252. Eng. Fl. vol. ii. p. 238. 609. 



4. P. Roberti. Robert's Knot-grass. Flowers axillar; leaves lance- 

 shaped, distant ; fruit shorter than the calyx, smooth. A large strag- 

 gling species, appearing intermediate between the preceding and follow- 

 ing. Annual : flowers in August and September : grows on the sea- 

 shore: common. Evg. Bot. Suppl. pi. 2805. Brit. Fl. 4th ed. p. 163. 



610. 



6, P. maritimunt. Sea-side Knot-grass. Flowers axillar; leaves 

 lance-shaped, fleshy, glaucous, crowded ; fruit longer than the calyx, 

 smooth. Annual : flowers in August and September : grows in the south 

 of England, and the Channel islands, on the sea-shore. Eng. Bot. Suppl. 

 pi . 2804. Brit. Fl. 4th ed. p. 1 64. 611. 



6. P. Fagopy'rum. Buck-wheat. Branks. Leaves between heart- 

 shaped and arrow-shaped ; stem nearly erect, without prickles ; angles 



of the seeds equal. Clusters many-flowered, panicled, spreading: 



flowers variegated with red, green, and white: the seeds furnish a nutri- 

 tious meal, which in some parts of England is made into thin cakes 

 called crumpets. It is usual for farmers to sow a crop of buck-wheat, 

 and plough it down for manure. Annual : flowers in July and August : 

 grows in cultivated fields, but is not indigenous. Eng. Bot. vol. xv. 

 pi. 1044. Eng. Fl. vol. ii. p. 239. 612. 



7. P. Convolvulus. Black Bind-veed. Leaves between heart-shaped 

 and arrow-shaped ; stem twining, angular ; segments of the calyx 

 bluntly keeled ; fruit striated with minute points. Stem twining to the 



