It. crispus: stem 2-3 feet high, with few branches; leaves long narrow, waved or crisped; whorls of flowers crowded in a long narrow panicle, one of the segments of the fruiting perianth bearing an oblong coloured tubercle or grain. - Roadsides and waste places. Fl. June to August.
‡‡ Segments ovate, not cordate.
R. Hydrolapathum: stem 3-5 feet high, slightly branched; leaves long, lanceolate, pointed; panicle long, dense, leafy at the base, the branches scarcely spreading; inner perianth-segments ovate, entire or scarcely toothed, with a large oblong tubercle on all three. - Edges of streams, pools, and ditches. Fl. July, August.
It. conglomerate: stem 2-3 feet high; leaves cordate-oblong, pointed; panicle with spreading branches and distant whorls; inner perianth-segments narrow-ovate, equal, each with an oblong tubercle. - Waste places. Fl. June to August.
It. sanguineus: stem two feet high, branched: leaves lanceolate, cordate at the base; panicle leafy at the base, with stiff, slender, spreading branches, the whorls of flowers distinct; inner perianth-segments narrow, entire or scarcely-toothed, one with a large tubercle. - Roadsides and waste places. Fl. June to August.
†† Inner perianth-segments toothed. R. obtusifolius: stem 2-3 feet high, slightly branched; leaves cordate-oblong, obtuse; whorls of flowers distant; inner segments of the perianth bordered below the middle by a few small teeth, usually ending in a narrow entire point. - Waste ground. Fl. July to September.
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, 1/4-1 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.