io aa} 
Atriplex. | LXII, CHENOPODIACEZ. 379 
On the seacoasts and in the saline districts of Hurope, Asia, and 
Africa, but not extending to the Arctic regions. Not uncommon round 
the British Isles. 7. summer and autumn. 
oo 
LXIII. POLYGONACEA, THE POLYGONUM FAMILY. 
Herbs, or in some exotic species, shrubs, with alternate 
leaves, and thin, scarious stipules, forming a sheath or ring 
round the stem within the leafstalk. Flowers small, herba- 
ceous or sometimes coloured, clustered in the axils of the leaves 
or in spikes or racemes, forming terminal panicles. Perianth 
of 6, 5, or fewer segments, regular and equal, or the inner ones 
enlarged. Stamens variable in number, never more than 8 in 
the British species. Ovary free, with a single ovule, but with 
2, 3, or more styles or stigmas. Fruit a small, seed-lhke nut, en- 
closed in the persistent perianth. Embryo of the seed straight 
or curved, in a mealy albumen. 
A considerable Order, dispersed over every part of the globe, from 
the hottest. tropical plains to the extreme Arctic regions, or to the 
highest mountain summits, close to the limits of perpetual snows. 
Some tropical species are tall, woody climbers, or erect shrubs, but the 
majority of the Order are herbs approaching Chenopodiacee in char- 
acter, and sometimes in habit, but always readily known by their 
sheathing stipules, even when reduced to a narrow ring or a mere line 
surrounding the stem. They also very seldom acquire any of the 
mealiness of Chenopodiacee. 
Fruiting perianth of 6 segments, 3 inner ones often enlarged . 6 Le RUNEEX. 
Fruiting perianth of 4 segments, 2 inner ones enlarged. ; a De” COS VER TEA 
Fruiting perianth of 5 nearly equal segments. i F ‘ . 8 POLYGONUM. 
The Rhubarbs of our gardeners and druggists are species of the genus 
Rheum, belonging to Polygonacew. 
1. RUMEX. DOCK. 
Herbs or shrubs, the British species all perennials, with a thick root- 
stock, and erect, furrowed annual stems; the thin sheathing stipules 
never fringed on the edge, but soon becoming torn or jagged. Lower 
leaves stalked and often large. Flowers numerous, small, herbaceous, 
though often turning red, usually pedicellate, in whorl-like clusters, 
axillary or in terminal racemes, often branching into panicles. Perianth 
deeply 6-cleft; when in fruit the 3 inner segments become enlarged 
and close over the triangular nut. Stamens 6. Styles 3, very short, 
with often tubercled, fringed stigmas. 
A considerable genus, spread over the greater part of the world, 
very readily distinguished from the rest of the Order, but the species 
vary so much in appearance that it is often very difficult to fix their 
real limits. They can also seldom be determined without the fruit- 
ing perianth, from which most of the characters are taken. They 
