This family contains a great variety and great number of species. It is divided into seven genera and many of these are further divided. They are all inconspicuous in flower and most of them are regarded as obnoxious weeds. The genus Rumex, to which our common Sorrels belong, contains seventeen species: that of Polygonum, which contains the Knot-weeds, has 32 species included in its six sub-genera. The scope and size of this book prevents even mention of the majority of these, so we have selected types most common, most conspicuous and most interesting.

Field Or Sheep Sorrel (Rumex Acetosella)

Field Or Sheep Sorrel (Rumex Acetosella) has dioecious flowers that is staminate and pistillate ones grow on different plants. They are tiny, perfect, greenish at first but later turning dark red, on branching spikes. The leaves are arrow-shaped, on slender petioles from the base, but smaller ones alternate along the plant stem that grows from 6 to 12 in. high; they are very acrid to the taste and usually turn reddish as the season advances, especially if in a dry locality. It is very common and a troublesome weed everywhere.

Lady's Thumb; Persicaria; Knotgrass (Polygonum Persicaria) (European)

This is a very common weed everywhere in damp places, especially about farm houses. The small, crimson-pink flowers are in dense spikes terminating the branching stems that are from 1 to 3 feet high. The lanceolate, pointed leaves, that alternate along the angled and sheathed stem, are rather rough and usually have a dark triangular spot in the middle.

A. Lady's Thumb ; Persicaria.

Polygonum persicaria.

B. Smartweed.

Polygonum Hydropiper.

Common Smartweed; Water Pepper (P. Hydropiper)

Common Smartweed; Water Pepper (P. Hydropiper) has similar shaped flowers of a greenish color. The leaves are lanceolate and very acrid. It is very abundant in wet places throughout our range.