SPECIES AND VARIETIES. 313 



a few small teeth, usually ending in a narrow entire point. — 

 Waste ground. Fl. July to September. 



** Leaves hastate, i. e. with acute basal auricles. 



R. Acetosa : stems scarcely branched, 1-2 feet high ; leaves 

 oblong, sagittate at the base, very acid ; flowers dioecious, in 

 long, terminal, leafless panicles, usually turning red, the inner 

 segments of the fruiting perianth enlarged, orbicular, entire, 

 almost petal-like. — Sorrel. — Meadows and pastures. Fl. May, 

 June. 



R. Acetosella : stems slender, ^-1 foot high, often turning 

 red ; leaves narrow-lanceolate, sagittate, the lobes of the base 

 usually spreading ; flowers small, dioecious, in slender terminal 

 panicles ; inner perianth-segments broadly ovate or orbicular, 

 scarcely enlarged. — Sheep Sorrel.-^ Dry open pastures. Fl. 

 May to July. 



(260) Oxyria. 



O. reniformis ; leaves glabrous, cordate-orbicular or kidney- 

 shaped, acid; stem slender and almost leafless, 6-10 inches 

 high, terminating in a simple or slightly-branched raceme; 

 flowers small. — High mountain ranges. Fl. July, August. 



(261) Polygonum. 



* Stems prostrate loiry hranched, or simple and floating. 



P. aviculare : annual ; stems often 1-2 feet long ; stipules 

 white, scarious, becoming ragged at the edges; leaves small, 

 narrow-oblong ; flowers small, shortly stalked, clustered in 

 the axils of the leaves. — Knotgrass. — Cultivated and waste 

 places. Fl. May to September. 



P. maritimum is distinguished by its thicker stems, larger 



