Polygonum.) © ° LXIII. POLYGONACER. 385 
It varies much in its branches, sometimes very long and slender, with very 
few distant leaves, sometimes short and densely matted, with the small 
leaves much crowded. A maritime variety, distinguished under the name 
of P. littorale, Link., with rather thicker leaves and larger flowers and 
nuts, has been sometimes confounded with young or luxuriant specimens 
of P. maritimum, but has not the shining nuts of that species. 
2. P.maritimum, Linn. (fig. 868). Sea Polygonum.—When flower- 
ing the first year of its growth, or when luxuriant, this species is distin- 
guished from P. aviculare by its thicker stems, larger and thicker, more 
glaucous leaves, larger scarious stipules, brown and much veined at the 
base, larger flowers, and especially by the nuts, often 2 lines long, project- 
ing beyond the perianth, and very smooth and shining. Older specimens, 
grown in drier sands, have a woody, perennial stock, with short, thick 
branches, completely covered by the stipules, the interncdes being all very 
short. 
In maritime sands, on most of the seacoasts of the northern hemisphere, 
and here and there also in the south. Common on the south coast of Eng- 
land and the Channel Islands.: #1. end of summer and autumn. It is 
considered by American botanists as a variety of P. aviculare. The P. 
Roberti, Loisel, or P. Ratz, Bab., is rather a young or a luxuriant state 
of this plant than a distinct variety, although those names are sometimes 
given to the maritime variety of P. aviculare. 
3, P. Convolvulus, Linn, (fig. 869). Climbing Polygonum, Climbing 
Buckwheat, Black Bindweed.—A glabrous annual, with a twining stem as 
in Convolvulus. Stipules short. Leaves stalked, heart-shaped or broadly 
sagittate, and pointed. Flowers'in little loose clusters ; the lower ones axil- 
lary, the upper ones forming loose, irregular terminal racemes. Styles 3. 
Fruiting perianth not 2 lines long; the 3 outer segments closely surround- 
ing 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, Frequentin Britain. 
Fl, summer and autumn. 
4, P. dumetorum, Linn. (fig. 870). Copse Polygonum.—Stem, 
foliage, and inflorescence of P. Convolvulus, 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, which is often 
decurrent on the pedicel, the whole perianth being often 3 lines 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 P. Convolvulus. In Britain, chiefly in the southern counties of 
England. FV. end of summer, and autumn. 
5. P. viviparum, Linn. (fig. 871). Viviparous Polygonum,—Stock 
perennial and tuberous, with simple, erect, slender stems, 4 to 6 or rarely 
8 inches high. MJadical leaves on long stalks, narrow-oblong or linear ; 
stem-leaves few, nearly sessile or clasping the stem. Spike solitary and 
terminal, slender, 14 to 3 inches long. Flowers, when perfect, pale flesh- 
coloured, and small, with 3 styles, but the lower ones, and sometimes all, 
are converted into little red bulbs, by which the plant propagates. 
Cc 
