86 
Dicotyledons with Incomplete Flowers . 
Natural Order 
POLYGONACE2E. Tab. 70. 
Diagnosis.— -Herbs (or exotic shrubs) with alternate leaves and sheathing 
stipules. Perianth small, regular, often petaloid. Stamens 6-10. Ovaiy 
free, 1-celled, with 1 erect ovule, and 2-3 stigmas. Embryo straight or 
curved in mealy albumen. 
Distribution.. —A rather large cosmopolitan Natural Order, ranging from the Equator to the 
extremes of flowering vegetation. The woody species are mostly Tropical. 
Number of British Genera, 3; Species, 27. 
STIPULES almost invariably present and very characteristic, usually sheathing the stem as in Persicaria 
{Polygonum) and Dock {Rumex). 
Flowers pentamerous, tetramerous, or in Dock {Rumex) and Rhubarb {Rheum) trimerous, the 3 inner segments 
of the perianth enlarging after flowering. 
Stamens in Polygonum usually not corresponding in number with the perianth-segments (ctnisomerous); in 
Dock 6, in Rhubarb 9. 
USES, &c. — The valuable drug Rhubarb is the root of an Asiatic species of Rheum {R. officinale); 
Rhubarb of greengrocers, the acid leaf-stalks {petioles) of the large radical leaves of two or three species of the 
same genus. Sorrel {Rumex scutatus ), with herbage similarly acid, is used as salad. Buckwheat {Polygonum 
Fccgopyrum and P.tataricum) is largely cultivated, both in Europe and Asia, for its farinaceous seeds used in lieu 
of corn, and in Britain for feeding game and poultry. A few species of Polygonum are grown in gardens for 
ornament, as the tall shrubby P. orientate and the dwarf creeping P. Brunonianum , both of Asiatic origin. 
