380 THE POLYGONUM FAMILY. [Rumex. 



may be readily distributed into two distinct sections, Rumex proper 

 and Acetosa. 



Leaves never hastate at the base (though often cordate, with 

 obtuse auricles). Flowers mostly hermaphrodite (Ru- 

 mex.) 

 Inner perianth-segments entire, or with one or two scarcely 

 perceptible teeth. 

 Segments broadly ovate, more or less cordate. Panicle 

 narrow and crowded when in fruit. 

 No tubercle on any of the perianth-segments . . 1. R. aquaticus. 

 A tubercle on one at least of the perianth-segments . 2. R. crispus. 

 Segments ovate, not cordate. 

 Tall water-plant. Lower leaves above a foot long. 

 Panicle erect. A tubercle on all three perianth- 

 segments 4. R. Hydrolapathum. 



Plant seldom above 3 feet. Lower leaves not a foot. 

 Panicle very spreading. Perianths small. 

 A tubercle on all three perianth-segments . . 5. R. conglomeratus. 



A tubercle on one segment only 6. R. sanguineus. 



Inner perianth-segments toothed on the edge, one at least of 

 the teeth ending in a fine point. 

 Panicle erect. Pedicels longer than the perianth . . 3. R. obtiisifolius. 

 Panicle very spreading. Pedicels shorter than the fruit- 

 ing perianth. 

 Leaves chiefly radical. Pedicels thickened. Teeth of 



the perianth-segments stiff and short . . . 7. R. pulcher. 

 Panicle leafy. Perianths densely clustered with long 



fine teeth to the segments 8. R. maritimus. 



Leaves, at least the lower ones, hastate (with acute auricles). 

 Flowers mostly unisexual (Sorrels). 

 Leaves oblong or broadly lanceolate. Inner segments of 



the fruiting perianth enlarged and orbicular . . 9. R. Acetosa. 

 Leaves narrow lanceolate or linear. Inner segments of the 



fruiting perianth not enlarged 10. R. Acetosella. 



Besides the above, R. alpmus, Linn., from the mountains of con- 

 tinental Europe, formerly cultivated for its root, a very broad-leaved 

 species of true Rumex, with entire, grainless perianth-segments, and 

 the French Sorrel (R. scutatus), also a common plant in Continental 

 mountains, sometimes cultivated as a Sorrel, have both been met with 

 occasionally in Scotland or northern England, near the gardens from 

 which they had escaped, but neither of them appears to be really 

 established in Britain. 



1. It. aquaticus, Linn. (fig. 858). Smooth- Fruited D. — Closely re- 

 sembles the larger and denser-flowered forms of R. crispus, of which 

 it may be a luxuriant variety. The leaves are usually not so much 

 crisped, sometimes nearly flat, and often 9 or 10 inches long and full 

 3 inches broad; the panicle long and much crowded; but the chief 

 difference is in the inner segments of the fruiting perianth, which are 

 of the same shape, but have no tubercle, although a slight thickening 

 of the midrib may be sometimes observed. 



In rather rich and moist situations, in northern and Arctic Europe, 

 Asia, and America, and in the mountains of central Europe. In Britain, 

 confined to Scotland and the north of England. Fl. summer. 



2. R. crispus, Linn. (fig. 859). Curled D. — Stem 2 to 3 feet high, 

 with but few branches, usually short, and seldom spreading. Badical 

 leaves long and narrow, usually much waved or crisped at the edges, 

 and about 6 to 8 inches long, but varying much in size ; the upper ones 

 smaller and narrower gradually passing into mere bracts. Whorls of 



