Synonyms: Emex APNI*
Acetosa APNI*
Acetosella APNI*
Description: Perennial or annual herbs, usually erect, rarely rhizomatous, usually with a basal rosette of leaves, with or without stem leaves.
Leaves petiolate or subsessile, not articulate; nectaries absent; ocrea short-tubular, brown to whitish, membranous, entire but soon disintegrating.
Flowers usually bisexual (occasionally unisexual), clustered at nodes in simple or branched spike-like or panicle-like inflorescences. Perianth segments 6 (rarely 5), not winged or keeled, innermost 3 ('valves') enlarging and thickening in fruit, often producing marginal teeth and/or dorsal callosities. Stamens 6 (rarely 4 or 5); anthers basifixed. Style trifid, short; stigmas flattened, fimbriate, delicate.
Achene trigonous, enclosed in persistent perianth valves.
Distribution and occurrence: World: 194 species, cosmopolitan, chiefly in Northern Hemisphere temperate regions. Australia: 19 species, all States.
This genus is taken here in a wide sense, including several former segregates (Acetosa, Acetosella, Bucephalophora and Emex). Besides the native and naturalised species, R. sanguineus L. is occasionally cultivated for its edible leaves with bright red/purple veins but it is not known to be naturalised in NSW and is not included in the key.
Text by K. L. Wilson (1993); key updated by H. Sauquet (Oct 2020); text edited KL Wilson (Jan 2021)
Taxon concept:
Taxa not yet included in identification key
Rumex x pratensis
| | Key to the species | |
| 1 | Outer 3 perianth segments smaller than inner 3, not spiny or hardened | 2 |
| Outer 3 perianth segments in female flowers enlarged and hardened in fruit and produced in a rigid spreading spine; perianth segments subequal in male flowers | 4 |
| 2 | Flowers unisexual; inner 3 perianth segments scarcely exceeding the nut; leaves hastate | Rumex acetosella |
| Flowers mostly bisexual; inner 3 perianth segments much exceeding nut; leaves variable
Back to 1 | 3 |
| 3 | Leaves hastate or sagittate at base; inner 3 perianth segments membranous, inflated | 5 |
| Leaves rounded, cuneate or cordate at the base; inner 3 perianth segments leathery, not inflated, often toothed
Back to 2 | 6 |
| 4 | Visible part of 3 inner segments of fruiting perianth broad-triangular to broad-ovate, with a short pungent mucro; fruiting perianth 9–13 mm wide including spines (each 2–5 mm long) | Rumex hypogaeus |
| Visible part of 3 inner segments of fruiting perianth ± narrow-oblong, with an acute apex but without a pungent mucro; fruiting perianth 4–6 mm wide including the spines (each 1–2 mm long)
Back to 1 | Rumex spinosus |
| 5 | Erect tufted annual with fibrous roots; valves 12–23 mm long, c. 15 mm wide, often tinged bright pink or purplish | Rumex vesicarius |
| Perennial climber with thick tuberous roots; valves 4–7 mm long, 6–9 mm wide, straw-coloured at maturity, occasionally with pink or purplish tinge
Back to 3 | Rumex sagittatus |
| 6 | Fruiting valves without teeth | 7 |
| Fruiting valves with lateral teeth
Back to 3 | 9 |
| 7 | Callosities absent; fruiting valves 10–15 mm long | Rumex hymenosepalus |
| Callosities present; fruiting valves less than 7 mm long
Back to 6 | 8 |
| 8 | Fruiting valves 3.5–6 mm long and wide, with callosity small and not covering most of valve surface; fruiting pedicel 3–7 mm long; flower whorls close together, rarely lowermost subtended by a leaf | Rumex crispus |
| Fruiting valves 2.2–3.2 mm long, 1–1.7 mm wide, with callosity large and covering most of valve surface; fruiting pedicel 1–2.5 mm long; flower whorls distant and each whorl mostly subtended by a leaf
Back to 7 | Rumex conglomeratus |
| 9 | Valves either with 1–3 straight or slightly curved teeth on each side and a straight or slightly curved tip, or with margins much divided | 10 |
| Valves with 3–5 hooked teeth on each side and with a hooked tip
Back to 6 | Rumex brownii |
| 10 | Water plant with inflated prostrate and/or floating unbranched stems, rooting at nodes; callosities present as convex lumps not distinct from valves | Rumex bidens |
| Land plant with erect, often intricately branched stems, not rooting at nodes; callosities absent or present as distinct convex lumps on valves
Back to 9 | 11 |
| 11 | Basal leaves ovate-oblong or elliptic, c. 2–3 times as long as broad | 12 |
| Basal leaves linear to lanceolate, at least 5 times as long as broad
Back to 10 | 13 |
| 12 | Flower whorls more or less close together, without subtending leaf; fruiting pedicels slender, at least twice as long as valves, articulate well below middle | Rumex obtusifolius |
| Flower whorls distant, each with a subtending leaf; fruiting pedicels thick, c. as long as valves, articulate eventually c. midway along their length
Back to 11 | Rumex pulcher |
| 13 | Perennials; valves 2.5–6 mm long; plants drying green or brown but not orange; stems flexuous to intricate | 14 |
| Annual; valves 1.5–2.3 mm long; plants usually drying orange; stems erect
Back to 11 | Rumex crystallinus |
| 14 | Flowers 2–8 per whorl; leaves 8–20 mm wide, 5–20 times as long as broad | 15 |
| Flowers numerous per whorl; leaves c. 5 mm wide, 18–30 times as long as broad
Back to 13 | Rumex tenax |
| 15 | Valves broad-triangular, c. 3 mm wide, with 2 or 3 teeth on each side, callosities present or absent | Rumex dumosus |
| Valves narrowly tongue-shaped, c. 1.5 mm wide, with 1 spreading tooth near base on each side, callosities present
Back to 14 | Rumex stenoglottis |
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