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Rumex
crispus L. Standardized Common
Name: Yellow
Dock
Other Common Names: Curled Dock, Dock
Family: Polygonaceae
Taxonomy: Rumex
includes about 200 species, which are distributed worldwide and are often
weedy. Hybridization among species can occur; hybrids between R. crispus
and R. obtusifolius L. have been termed R. ×pratensis
Mert. & Koch. The recent Flora Europaea treatment recognizes three
slightly different subspecies, of which only subsp. crispus is
widespread.
Description: Perennial herb with
a thickened taproot. Leaves cauline and in a basal rosette; stem to 1.2(–1.5) m
tall, usually unbranched. Leaves in rosette usually ascending to nearly erect,
long-petioled, oblong to lanceolate, 20–30(–35) cm long; upper leaves smaller,
lanceolate, with short petioles; base rounded to subcordate, or sometimes
cuneate to truncate especially in stem leaves; apex acute; margins strongly crenate,
undulate and crisped; venation prominent, especially the midrib. Inflorescence
a narrow open panicle of dense racemes, mostly terminal, with smaller panicles
in axils of upper leaves, bracteate with leaflike bracts. Flowers small, borne
on long pedicels, perfect or unisexual and the plants monoecious; tepals 6, the
outer 3 remaining small, the inner 3 enlarging in fruit; stamens 6; ovary 1,
3-styled, 1-ovuled. Fruit an achene surrounded by thin wings formed by enlarged
tepals; wings forming a cordate or deltoid shape, 3–6(–8) mm long,
reticulate-veined, all 3 or only 1 with a tubercle; achene ovate, angled,
brown, shiny, 1.3–2.5(–3.5) mm long.
Parts
in Commerce:
Rhizome and root
Identification:
- Up to 35 cm
long, upper rhizome portion up to 7 cm in diameter, producing 1 to several
tap roots up to 2 cm thick
- Roots
cylindrical, tapering, often somewhat twisted, seldom branching
- Dark and often
reddish brown
- Upper portion of
rootstock (rhizome) bearing occasional circular scars, sometimes with stem
remains or buds; stems hollow, often purplish
- Roots
longitudinally wrinkled over entire surface when dry, bearing numerous
small, often transversely elongated rootlet scars and occasional rootlets
- Rootlets thin,
usually sparse except around rhizome, the thicker ones mostly confined to
the upper portion
- Fracture short,
dusty, sometimes splintery
- Inside of root
yellow to whitish
- Root in cross
section has thin brown cork layer; yellowish ring of cortex and phloem,
sometimes thick but tending to shrivel irregularly on drying; sometimes
brownish cambium; large yellowish wood with narrow interrupted xylem rays
separated by broader parenchyma rays (vessels are very large and may be
seen in cut surface with dissecting scope)
- Rhizome has a
central pith
- Roots grown in
very wet conditions may contain intercellular air spaces in parenchyma
- Taste
astringent, bitter
Adulterants: Adulteration is not
reported to be a problem, but it is questionable whether substitution of
related species would be noticed. Insufficient data on root morphology in this
genus are available to determine which species might be indistinguishable
substitutes. Several species have similar medicinal uses, of which the most
common is R. obtusifolius L. (Broad-Leaf Dock or bitter dock, also
sometimes called yellow dock). The roots of R. obtusifolius frequently
branch near the apex, and have more persistent rootlets than R. crispus;
the bark is usually very dark, but sometimes may be yellowish-brown.
References:
Laan P, Berrevoets MJ, Lythe S, Armstrong W, Blom
CWPM. Root morphology and aerenchyma formation as indicators of the
flood-tolerance of Rumex species. J Ecol. 1989;77:693–703.
Lousley JE, Kent DH. Docks and Knotweeds of the
British Isles. London: Botanical Society of the British Isles; 1981. BSBI
Handbook, No. 3.
Rechinger KH, revised by Akeroyd JR. Rumex.
In: Tutin TG, Heywood VH, Burges NA,
et al., eds. Flora Europaea. 2nd ed., vol. 1. Cambridge:
Cambridge University Press; 1993:99–107.
Youngken HW. Text-Book of Pharmacognosy, 5th ed. Philadelphia, PA: The
Blakiston Company; 1943:295–296.
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