Rumex obtusifolius |
Rumex lapponicus |
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bitter dock, broad-leaf dock, broad-leaf or broadleaf or bitter dock, patience a feuilles obtuses |
dock, green sorrel, Lapland dock, Lapland Mountain sorrel, Lapland or Lapland Mountain sorrel |
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Habit | Plants perennial, glabrous or ± papillose especially on veins of leaf blades abaxially, with fusiform, vertical rootstock. | Plants perennial, glabrous or nearly so, with short and relatively thin, horizontal or slightly oblique rootstock (usually not reaching deep into substrate) and ± crowded 2d-order roots (occasionally with short-creeping rhizome). |
Stems | erect, branched distal to middle or occasionally in distal 2/3, often with few flowering stems from rootstock, 60–120(–150) cm. |
erect, rarely ascending, several from base or often solitary, branched in distal 1/2 (in inflorescence), (10–)20–60(–100) cm. |
Leaves | ocrea deciduous to partially persistent at maturity; blade oblong to ovate-oblong, sometimes broadly ovate, 20–40 × 10–15 cm, usually less than 4 times as long as wide, base normally distinctly cordate, occasionally rounded, rarely truncate, margins normally entire, flat or undulate, rarely slightly crisped, apex obtuse or subacute. |
ocrea of at least middle and distal leaves with margins entire, not fringed, sometimes laciniate but only in distal parts; blade broadly ovate, rarely almost round, oblong-ovate, rarely oblong-lanceolate, 3–10(–14) × 1–4(–5) cm, normally less than 2.5 times as long as wide, base sagittate (with acute or subacute lobes directed downward, ± parallel to petiole, or slightly incurved inward), margins entire, normally flat, apex subacute or obtuse. |
Inflorescences | terminal, occupying distal 2/3 of stem, usually lax and interrupted, narrowly or broadly paniculate, branches usually forming angle of 30–45° with 1st-order stem. |
terminal, occupying distal 1/3 of stem, usually lax and interrupted especially in proximal part, narrowly paniculate or occasionally simple, cylindric (with 1st-order branches simple, or with few 2d-order branches). |
Pedicels | articulated in proximal 1/3 or rarely near middle, filiform, 2.5–8.5(–10) mm, articulation distinctly swollen. |
articulated near middle, filiform, 2–5 mm, articulation distinct. |
Flowers | 10–25 in lax whorls; inner tepals ovate-triangular, deltoid or, occasionally, lingulate, 3–6 × 2–3.5 mm (excluding teeth), ca. 1.5–2 times as long as wide, base truncate, margins usually distinctly dentate, rarely subentire, apex obtuse to subacute, straight, teeth 2–5, normally at each side of margin, short-subulate or triangular-subulate, straight, 0.5–1.8 mm, or shorter than width of inner tepals; tubercle usually 1, sometimes 3, then 1 distinctly larger, smooth. |
(2–)4–8 in whorls; inner tepals orbiculate, occasionally broadly ovate, 3.5–4.5 × 3.5–4.5 mm, base rounded or cordate, apex obtuse; tubercles small or occasionally absent. |
Achenes | brown to reddish brown, 2–2.7 × 1.2–1.7 mm. |
brown or dark brown to brownish yellow, 1.7–2.5 × 0.9–1.3 mm, dull. |
2n | = 40. |
= 14 (pistillate plants), 15 (staminate plants). |
Rumex obtusifolius |
Rumex lapponicus |
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Phenology | Flowering late spring–early fall. | Flowering late spring–summer. |
Habitat | Waste places, roadsides, fields, shores, meadows, wet woods, swamps | Meadows, rock outcrops, alluvial habitats along rivers and streams in tundra and montane and subalpine zones |
Elevation | 0-2300 m (0-7500 ft) | 0-2500 m (0-8200 ft) |
Distribution |
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; VT; WA; WI; WV; BC; NB; NF; NS; ON; PE; QC; SPM; Greenland; Europe; w Asia [Introduced in North America; introduced elsewhere]
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AK; MT; WY; AB; BC; NT; YT; Greenland; n Eurasia |
Discussion | Rumex obtusifolius, a member of subsect. Obtusifolii Rechinger f. (K. H. Rechinger 1937), is a polymorphic species represented in Eurasia by three or four rather distinct races often treated by European authors as subspecies or varieties. These taxa differ mostly in inner tepal dentation and geographic distribution. In North America the morphotypes often intergrade. In Eurasia this species is differentiated into predominantly western subsp. obtusifolius [including R. obtusifolius subsp. agrestis (Fries) Danser], eastern subsp. sylvestris (Wallroth) Rechinger f., intermediate central European subsp. transiens (Simonkai) Rechinger f., and montane subsp. subalpinus (Schur) Simonkai. Only subspp. obtusifolius and sylvestris occur in North America; the former seems to be more common. Subspecies obtusifolius differs from subsp. sylvestris in having larger and more prominently dentate inner tepals with one tubercle, or with three distinctly unequal tubercles; in subsp. sylvestris the teeth are usually less than 0.6 mm, developing only near the base of the inner tepals, and the tubercles often almost subequal. Rumex obtusifolius may be expected elsewhere in the Great Plains region of the United States and Canada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The name Rumex acetosa has been commonly misapplied to R. lapponicus. Native North American montane plants of the R. acetosa aggregate from the Rocky Mountains southward to Beartooth Plateau in Montana and Wyoming usually were referred to as R. alpestris [= Acetosa pratensis Miller subsp. alpestris (Jacquin) Á. Löve; A. pratensis subsp. arifolia (A. Blytt & O. C. Dahl) Á. Löve; R. arifolius Allioni, not Linnaeus f.; R. acetosa subsp. alpestris (Jacquin) Á. Löve; R. acetosa subsp. arifolius A. Blytt & O. C. Dahl]. Recent nomenclatural studies demonstrated that R. alpestris is an ambiguous name, which was probably based on plants belonging to R. scutatus Linnaeus (see I. O. Pestova 1998), and accepted the name R. arifolius for the predominantly European montane taxon. It differs from arctic plants, as well as from montane forms of the R. acetosa aggregate from southern Siberia and temperate North America, by its more robust habit, more branched inflorescence (similar to that of R. thyrsiflorus), and larger and more acute triangular-sagittate leaves (see A. I. Tolmachew 1966; N. N. Tzvelev 1989b; Pestova; R. Elven et al. 2000). Montane races possibly developed independently from R. lapponicus-like or R. acetosa-like ancestors, and they are still unclear taxonomically. Because of that, I prefer to keep those forms within R. lapponicus. The whole aggregate needs careful study; however, some authors prefer to include all arcto-montane Holarctic races of this aggregate in the collective and rather polymorphic R. alpestris in the broad sense (see Á. Löve 1944; Löve and D. Löve 1957). Some arctic plants from western Alaska may be conspecific with Rumex pseudoxyria (Tolmatchew) Khokhrjakov [= R. acetosa subsp. pseudoxyria Tolmatchew; Acetosa pseudoxyria (Tolmatchew) Tzvelev], a taxon described from arctic eastern Siberia (A. I. Tolmachew 1966). This entity is evidently closely related to R. lapponicus but differs from all other members of the R. acetosa group in having basal leaves less than two times as long as wide, almost hastate or at least rounded-truncate at base, resembling those of Oxyria digyna (Linnaeus) Hill, cauline leaves small or completely reduced, and inflorescence occupying more than one-half of the stem; the plant itself is also somewhat similar in appearance to the European alpine species R. nivalis Hegetschweiler. According to E. Hultén (1973), his Rumex arcticus var. perlatus, described from a single specimen collected at Tin City, Seward Peninsula, Alaska, agrees perfectly with the original description of R. acetosa subsp. pseudoxyria. It is unlikely that Hultén would confuse two rather distantly related groups. There is also a possibility that var. perlatus is identical with R. arcticus var. latifolius Tolmatchew (see discussion under R. arcticus). Additional collections are needed to confirm the occurrence of R. pseudoxyria in northwestern North America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 526. | FNA vol. 5, p. 503. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Rumex > subg. Rumex > sect. Rumex | Polygonaceae > subfam. Polygonoideae > Rumex > subg. Acetosa |
Sibling taxa | ||
Synonyms | R. crispatulus, R. rugelii | R. acetosa subsp. lapponicus, Acetosa alpestris subsp. lapponica, Acetosa lapponica, R. alpestris subsp. lapponicus |
Name authority | Linnaeus: Sp. Pl. 1: 335. (1753) | (Hiitonen) Czernov: in B. N. Gorodkov and A. I. Pojarkova, Fl. Murmansk. Obl. 3: 154. (1956) |
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