Polygonum. | LXIII, POLYGONACER. 387 
and the nuts usually concave on both sides, but these characters are not 
constant. 
In cornfields and waste places, with nearly the same range as P. Per- 
sicaria, but usually in richer soils, and does not extend so far north. In 
Britain not uncommon. FU. summer and autumn. Specimens agreeing 
with P. Persicaria in everything but the glandular dots, have been 
described as a third species under the name of P. laxum or P. nodosum, 
10. P. Hydropiper, Linn. (fig. 876). Waterpepper Polygonum.— 
Stature and foliage nearly as in P. Persicaria, but a more slender plant, 
often decumbent or even creeping at the base, the stipules more fringed at 
the top, the leaves narrower, and the flowers in slender spikes, often 2 or 3 
inches long, more or Jess nodding, the clusters of flowers almost all distinct, 
and the lower ones often distant and axillary. Perianths, and often the 
bracts and stipules or other parts of the plant, dotted with small glands, 
and the whole plant is more or less acrid or biting to the taste. 
In wet ditches, and on the edges of ponds and streams, throughout 
Europe and central and Russian Asia to the Arctic regions. Abundant 
in England and Ireland, more rare in the Scotch Highlands. £7. swmmer 
and autumn. 
11. P. minus, Huds. (fig. 877). Slender Polygonum.—Very near P. 
Hydropiper, and probably a mere variety. It is usually a smaller plant, 
with rather smaller flowers, in closer, although slender spikes, and has 
neither the glandular perianths nor the biting flavour of that species. 
In ditches and waste places, on roadsides, etc., over the whole range 
of P. Hydropiper. In Britain, not so common as that species, and 
scarcely extends beyond the middle of Scotland. Fl. summer and autumn. 
The smaller, most distinct form is usually found in drier situations. When 
growing in richer, wet situations, it can only be distinguished from P. 
Hydropiper by the absence of the glands on the perianth. This form has 
been published under the name of P. mite, Schrank, and is confined to 
England, It is not improbable that further observation may show that 
this and the last three Polygonums are all varieties of one species. 
LXIV. THYMELEACER, THE DAPHNE FAMILY. 
A family limited in Britain to the single genus Daphne. 
The exotic genera associated with it differ chiefly in the number 
of the stamens and in the number and form of the divisions of 
the perianth, or'in the consistence of the fruit. 
The species are rather numerous in southern Africa and Australia, 
including among the latter the Pimeleas of our greenhouses, with a few 
from the tropics or the northern hemisphere. 
I. DAPHNE, DAPHNE. 
Shrubs, or, in some exotic species, trees, with alternate or rarely 
opposite entire leaves, and no stipules; the flowers either coloured or 
sometimes green, either lateral, or, in exotic species, terminal. Perianth 
inferior, deciduous, with a distinct tube and a spreading 4-cleft limb. 
Stamens 8, inserted in the top of the tube. Ovary free within the tube, 
cca 
