THE PERSICARIA FAMILY 
123 
1. Black Bindweed, Climbing- Persiearia, op Buckwheat. (Polygonum Con- 
volvulus. Linn.) — As just described. A species with greenish-white flowers often tinged with 
red, in little loose clusters in the axils of the leaves ; the perianth enlarged in fruit, the 3 outer 
lobes being keeled or rarely winged ; 8 stamens, 3 styles, and a 3-sided nut-like fruit ; the 
angular stem twining, as in Convolvulus, round the neighbouring plants, some two or three feet in 
length ; and the leaves all stalked, shining, heart-shaped (cordate) or arrow-shaped (sagittate), and 
pointed, with entire semi-cylindrical sheaths. In the autumn the leaves are sometimes a very 
beautiful red. \Plate 4 r . 
Very common. In fields, cultivated ground, and waste places ; throughout England, Scotland, 
and Ireland. July — September. Annual. 
2. Copse Buckwheat. (Polyg-'onum dumetbrum. Linn.)— A very similar species, more 
luxuriant, with larger clusters of flowers which have a broad white membranous wing on the back of 
the 3 outer perianth lobes just continuing down the flower-stem, and a round stem, 3-5 feet in 
length. 
Rare. In hedges and thickets, only in the south of England. July — September. Annual. 
3. Common Knot-grass. (Polyg-'onum avicul&re. Linn.) — A very common little weed 
with 1-3 pink or greenish-white flowers in clusters in the axils of almost all the leaves, either 
distant from one another or so near as to form a leafy spike ; the 5-lobed perianth is hardly 
enlarged in fruit ; the stamens are 8 in number ; the styles 3 ; and the nut 3-sided, not shining, 
about as long as the perianth. The stem is from a few inches to 2 feet long, much branched, 
wiry, prostrate or erect ; the leaves are small, shortly stalked or the upper ones stalkless (sessile), 
oval, oblong, or strap-shaped, and entire ; and the stipules are white, membranous, sometimes 
long, with a few veins, at length torn. \Plate 41. 
This species varies very much in its growth according to the soil and situation in which it is found. 
Many varieties are given ; one, Polyg"Onum litorale. Link., a seaside variety, it would be well 
to note, as it is easily mistaken for the Seaside Knot-grass (Polygonum maritimum) because of its 
similar thick, rather fleshy leaves, and larger flowers and nuts than those of the ordinary Knot-grass. 
It has not, however, the smooth shining nuts of the Seaside Knot-grass. 
Very common. In cultivated and waste ground ; throughout England, Scotland, and Ireland. 
May — October. Annual. 
4. Ray’s Knot-grass. (Polyg-'onum R&ii. Bab.) — A very similar species to the last, 
intermediate between it and the next, but with rather larger flowers, shining nuts which are much 
longer than the perianth ; long, straggling, prostrate stems, and oblong, lance-shaped leaves which 
bend towards the stem and are often covered with bloom (glaucous). 
Not uncommon. Sandy sea-shores ; in England, Scotland, and Ireland. August — September. 
Annual or biennial. 
5. Seaside Knot-grass. (Polyg onum marit imum. Linn.)— A similar species to the 
Common Knot-grass (Polygonum aviculare) and to the last species. Like the last in the long 
shining nut, but more shrubby, with prostrate, stiff, woody stems often buried in the sand, and 
fleshy leaves with the margins rolled back (revolute) and the leaves diverging from the stem. 
Very rare. On sandy sea-shores in the south of England and in the Channel Isles. July— 
September. Perennial. 
6. Water Pepper, Biting Persiearia. (Polyg onum Hydrop iper. Linn.)— Flowers 
greenish, i inch long in long, slender, drooping spikes terminating the stem and branches ; perianth 
5-lobed, dotted all over with conspicuous glands, scarcely enlarged in fruit ; stamens usually 6, 
rarely 8 ; styles usually 2 when the nut-like fruit is compressed, or 3 when the nut is 3-sided. 
k 2 
