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Rumex
See list of 18 species in this genusPedicel measurements in the identification key include the actual pedicel (the proximal portion below the articulation point) and the pseudopedicel (the distal portion above the articulation point that is formed by the stipe-like hypanthium base). Complete specimens with mature fruit are crucial for confident identification of most species in our area. Rumex conglomeratus Murr. was reported from MA by Mosyakin (2005), but specimens are unknown. Rumex sanguineus L. was reported from CT by Hultén and Fries (1986), but specimens are unknown. Reference: Rechinger (1937).
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1a. Leaf blades sagittate or hastate; plants dioecious
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2a. Leaf blades predominantly sagittate; inner tepals of carpellate flowers 4–6 mm long in fruit, at least 1 of the them developing a tubercle; tepals of staminate flowers 2–3 mm long; achenes 2–2.5 mm long
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2b. Leaf blades predominantly hastate; inner tepals of carpellate flowers 1.2–3.5 mm long in fruit, none of them developing tubercles; tepals of staminate flowers 1.5–2 mm long; achenes 0.9–1.5 mm long
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3a. Inner tepals of carpellate flowers 1.2–1.7 (–2) mm long in fruit, about as long as the achene, unexpanded, not reticulate-veiny; pedicels articulated near summit just below origin of tepals; stems arising from thin, creeping rhizomes
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3b. Inner tepals of carpellate flowers 2.5–3.5 mm long in fruit, much surpassing the achene, accrescent and becoming reticulate-veiny; pedicels articulated in the basal portion; stems arising from a taproot
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1b. Leaf blades without basal lobes; plants synoecious, monoecious, or polygamous
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4a. Inner tepals (i.e., valves) with prominent teeth or spines on the margins [Fig. 801]
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5a. Margins of the inner tepals with 2 or 3 (–4) slender spines 0.5–2.7 mm long; achenes 0.9–1.75 mm long; basal leaf blades narrow-lanceolate to lanceolate or oblong-lanceolate, 4–7 times as long as wide; all 3 of the inner tepals with an enlarged tubercle on the midrib; plants fibrous-rooted annuals
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6a. Abaxial leaf blade surface and branches of inflorescence glabrous or inconspicuously papillose; leaf blades narrow-cuneate at base (rarely to broad-cuneate); tubercle of inner tepals usually smooth (infrequently finely striate or obscurely pitted)
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6b. Abaxial leaf blade surface and branches of inflorescence papillose-pubescent; leaf blades truncate to subcordate at base (rarely broad-cuneate); tubercule of inner tepals distinctly reticulate-pitted
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5b. Margins of the inner tepals with 2–6 teeth (0.2–) 0.8–1.5 mm long [Fig. 801]; achenes (1.8–) 2–2.8 mm long; basal leaf blades oblong or oblong-lanceolate to ovate-oblong or obovate-elliptic, up to 4 times as long as wide; only 1 of the inner tepals with an enlarged tubercle on the midrib (all 3 with tubercles in R. violascens); plants taprooted perennials (usually annual or biennial in R. violascens)
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7a. Inner tepals all bearing an enlarged tubercle on the midrib, with marginal teeth 0.2–0.5 mm long; basal leaf blades cuneate to rounded at the base (rarely truncate)
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7b. Only 1 of the inner tepals with an enlarged tubercle on the midrib, with marginal teeth 0.8–1.5 mm long; basal leaf blades truncate to cordate at the base (rarely broad-rounded)
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8a. Basal leaf blades 20–40 cm long; tubercles smooth [Fig. 801]; branches of inflorescence ascending, usually diverging from primary axis at an angle of 30–45 degrees; stems 60–120 (–150) cm tall
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8b. Basal leaf blades 4–10 (–15) cm long; tubercles usually verrucose; branches of inflorescence spreading, usually diverging from primary axis at an angle of 60–90 degrees; stems 20–60 (–100) cm tall
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4b. Inner tepals with entire or obscurely erose margins
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9a. Stems with lateral branches and/or axillary leaf tufts, lacking a basal rosette of leaves [Fig. 802]; leaf blades usually pale-green or glaucous, with flat, entire to undulate margins
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10a. Pedicels 10–17 mm long, 3–5 times as long as associated inner tepals, articulated near base; tubercle extending below the base of perianth [Fig. 803]
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10b. Pedicels (2–) 3–8 mm long, 1–2.5 times as long as associated inner tepals, articulated in the proximal ⅓ (sometimes near base); tubercle not extending below base of perianth
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11a. Inner tepals with a broad tubercle, the tubercle more than half as wide and nearly as long as its associated inner tepal; leaf blades mostly 7–10 times as long as wide; plants predominantly of coastal marshes and shorelines
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11b. Inner tepals with a narrow tubercle, the tubercle less than half as wide and much shorter than its associated tepal; leaf blades mostly 2.5–6 times as long as wide; plants predominantly of freshwater wetlands and inland disturbed habitats
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12a. Inner tepals 4.5–6 ×3–4.5 (–5) mm, 1–3 of them developing tubercles; leaf blades lanceolate to elliptic-lanceolate or broad-lanceolate, the larger 30–55 mm wide, mostly 2.5–4 times as long as wide; achenes 2.5–3.5 mm long
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12b. Inner tepals (2–) 2.5–3.5 (–3.8) × (2–) 2.5–3 (–3.5) mm, usually all 3 of them developing tubercles; leaf blades narrow-lanceolate, the larger 10–40 (–50) mm wide, mostly 5–6 times as long as wide [Fig. 802]; achenes 1.7–2.2 mm long
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9b. Stems lacking both lateral branches and prominent axillary leaf tufts, with a usually conspicuous rosette of basal leaves [Fig. 800]; leaf blades dark green to red-green, with crenate, undulate, and/or crisped margins
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13a. Plants with rhizomes; lower leaf blades broad-ovate to orbicular, ± as long as wide; inner tepals without tubercles
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13b. Plants with vertical taproots, lacking rhizomes; lower leaf blades narrow-lanceolate or lanceolate to oblong-lanceolate or narrow-ovate-triangular, usually more than 3 times as long as wide; inner tepals with or without tubercles
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14a. Inner tepals lacking well-developed tubercles (rarely the midrib of 1 tepal slightly thickened in R. longifolius)
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15a. Pedicels with a distinct articulation point that is swollen and thicker the remaining pedicel; inner tepals broad-orbicular to reniform, (4.5–) 5–6 (–7) mm long
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15b. Pedicels with an indistinct articulation point that is scarcely, if at all, thicker than the remaining pedicel; inner tepals ovate or broad-ovate-triangular to suborbicular, 5–10 (–12) mm long
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14b. At least 1 of the inner tepals with a well-developed tubercle
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16a. All 3 of the inner tepals with a tubercle, the tubercles equal in size or nearly so; pedicels with an indistinct articulation point that is scarcely, if at all, thicker than the remaining pedicel; native plants of wetlands and shores
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16b. One to 3 of the inner tepals with a tubercle, when 3, then 1 of the tubercles distinctly larger or smaller than the others; pedicels with a distinct articulation point that is swollen and thicker than the remaining pedicel; non-native plants primarily of disturbed habitats, occasionally in wet places such as ditches and shorelines
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17a. Inner tepals 5–8 (–10) ×5–9 (–10) mm, usually only 1 of the tepals with a tubercle (rarely as many as 3 tepals with tubercles); tubercle (or the largest one) up to 33% as long as associated inner tepal measuring from the base of the tubercle; achenes 3–3.5 mm long; leaf blades broad-lanceolate to oblong-lanceolate, with plane or slightly crisped margins
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17b. Inner tepals 3.5–6 ×3–5 mm, usually all of the tepals with a tubercle (rarely only 1); largest tubercle 40–60% as long as associated inner tepal measuring from the base of the tubercle; achenes 2–3 mm long; leaf blades lanceolate to narrow-lanceolate, with prominently crisped margins
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Each photo represents one species in this genus.