LV. — SHEEP’S SORREL. 
Rumex Acetosella Linne. 
E NGLER’S ninth Order of Dicotyledons, the Polygonales, is co-extensive with 
the Family Polygonacea. This is an extensive group of plants, mainly 
herbaceous and belonging to the North Temperate Zone, and includes three or four 
well-known genera : Rumex , the Docks and Sorrels ; Polygonum , the Knot-grasses; 
Fagopyrum , the Buckwheats ; and Rheum , the Rhubarbs. Among the chief characters 
in which they agree are those of the leaves and their stipules and those of the ovary 
and ovule and the resultant fruit and seed. The leaves are scattered, simple, 
revolute in the bud, with sheathing petioles and ochreate stipules, that is to say that 
the two stipules, which are generally membranous, are united by both margins so as 
to form a sheath round the stem. Though the perianth persists round the fruit, 
the ovary is superior and is not adherent to it, and almost always forms a triangular 
nut, one-chambered and containing one erect unbent ovule springing from its base 
and forming a seed with floury albumen. The flowers are usually perfect and 
polysymmetric and generally small, but often so massed as to form handsome 
inflorescences ; and, since they generally secrete nectar, they are mostly, but by no 
means universally, insect-pollinated. In the fruiting stage the persistent perianth 
generally forms a membranous wing, so that dispersal by wind is facilitated ; but in 
some members of the Family the fruits are provided with hooks so as to form burs 
to adhere to the coats of passing animals. 
The underground parts of some species are astringent or purgative, and the 
green parts are often very rich in oxalic and malic acids, chiefly probably in the 
form of acid binoxalate and malate of potash. This renders some of them useful as 
vegetables, though others are too pungent ; and possibly this acidity of their sap 
may be connected with the red colouring-matter with which the stems, leaves, and 
perianths of many members of the group are deeply tinged. 
An important distinctive character within the Family is the arrangement of the 
perianth-leaves, which may be either cyclic, that is in whorls, in this case of three 
leaves each, or acyclic , that is in a spiral, when they are generally five in number. 
The two large genera Rumex and Polygonum belong to these two Sub-Families, which 
have been termed Rumicoide<e and Polygonoide<e. 
The names of the genus Rumex have an interesting history. Rumex itself is 
supposed to be the name of some kind of spear, the pointed hastate , or halberd-shaped, 
leaves being strikingly characteristic of many of the species. Pliny makes use of 
the name, but speaks of the acid-leaved Sorrels, such as Rumex Acetosa Linne and 
R. Acetosella Linne, under the name Oxalis. This name remains in Lobel and 
Gerard. The former writes of our Sheep’s Sorrel in 1 570 : — 
“Oxalis tenuifolia — Oseille de brebis . . . tanto luxu sabulosls . . , Angliae oportuna.' 
