450 THE POlTGOKfM TAMILT. 



In maritime sands, on most of the seacoasts of the northern hemisphere, 

 and here and there also in tlie south. Common on the British coasts. Fl. 

 end of summer, and autumn. It is considered by American botanists as a 

 variety of the Knot-weed P. The P. Roherti or P. Sail (Eng. Bot. Suppl. 

 t. 2805) is rather a young or a hixm-iant state of this plant than a distinct 

 variety, although those names are sometimes given to the maritime variety 

 of the Knotweed P. 



3. Climbing Polygonum. Polygonum Convolvulus, Linn. 

 (Eng. Bot. t. 941. Climbing Buckwheat. BlacJc Bindweed.) 



A glabrous annual, with the twining stem of a Convolvulus. Stipules 

 short. Leaves stalked, heart-shaped or broadly sagittate, and pointed. 

 Flowers in httle loose clusters ; the lower ones axUlary, the upper ones 

 forming loose, irregular terminal racemes. Styles 3. Fruiting periantli 

 not 2 lines long ; the 3 outer segments closely surrounding the triangular 

 nut, and sometimes sharply keeled on the midrib, but not winged. 



In cultivated and waste places, throughout Europe, in central and Rus- 

 sian Asia, and North America, to the Arctic regions. Frequent in Britain. 

 Fl. summer and autumn. 



4. Copse Polygonum. Polygonum dumetorum, Linn. - 



(Eng. Bot. Suppl. t. 2811.) 



Stem, foliage, and infloreseenoe of the climbinff P., of which it may be a 

 mere variety ; but it is more luxuriant, and the 3 angles of the fruiting 

 perianth are more or less expanded into a white, scarious wing, wliich is 

 often decurrent on the pedicel, the whole perianth being often 3 hnes long. 

 The nut is also usually more shining. 



In hedges, open woods, or rich, cultivated places, in Europe, Russian 

 Asia, and North America, but not so common, nor extending so far north- 

 ward, as the climbing P. In Britain, chiefly in the southern counties of 

 England. Fl. end of summer, and autumn. 



5. Viviparous Polygonum. Polygonum viviparum, Linn. 



(Eng. Bot. t. 669.) 



Stock perennial and tubei-ous, with simple, erect, slender stems, 4 to 6 or 

 rarely 8 inches high. Radical leaves on long stalks, narrow-oblong or linear; 

 stem-leaves few, nearly sessile or clasping the stem. Spike solitary and ter- 

 mmal, slender, 1^ to 3 inches long. Flowers, when perfect, pale flesh- 

 coloured, and small, with 3 styles, but the lower ones, and sometimes aU, 

 are converted into httle red bulbs, by which the plant propagates. 



In alpine pastures, often at great elevations, in aU the great mountain- 

 ranges of Europe and Asia, descending to lower levels in the north, and 

 penetrating far into the Arctic regions. Frequent in the Highlands of 

 Scotland, and occurs also in northern England and North Wales, but is not 

 recorded from Ireland. Fl. summer. 



6. Bistort Polygonum. Polygonum Bistorta, Linn. . 



(Eng. Bot. t. 509. Bistort. Snakeweed.) 



Perennial rootstock thick, and often spreading considerably. Radical 



leaves in broad patches, on long stalks, ovate-lanceolate or cordate, often 



3 to 6 inches long. Stems simple and erect, 1 to 2 feet high, with a few 



nearly sessile leaves, and terminating in a single, dense, oblong, or cyhndri- 



