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Taraxacum
officinale Weber ex Wigg.
Standardized Common
Name: Dandelion
Other Common Names: Common Dandelion,
Dumble-dor, Pissenlit
Family: Asteraceae
(Compositae)
Taxonomy: Taraxacum
includes perhaps 60 species, some of which are cosmopolitan weeds. Sect. Taraxacum
consists primarily of T. officinale (in the broad sense). This is a
usually asexual species, which has numerous slightly different triploid and
tetraploid forms that propagate themselves without interbreeding and thereby
maintain their individual features. As a result, literally hundreds of European
races of T. officinale have been described as species. The biological
concept of a species as a set of interbreeding populations is inapplicable to
asexually reproducing species, and no practical justification exists for
recognizing any of these entities.
Description: Perennial herb with
short rhizome at the top of a long, cylindrical, branching taproot. Leaves all
basal, short-petioled, spatulate to oblanceolate or occasionally obovate, to 40
cm long, 6 cm broad, membranous; base attenuate into petiole; apex obtuse;
margins with large irregular, often backward-pointing teeth or nearly entire;
upper surface dark green, lower surface pale. Inflorescence a head (capitulum),
solitary, 2–5 cm in diameter; scape hollow, often purplish, containing white
latex; involucre green, with 2 whorls of phyllaries, the outer short, the inner
much longer and linear; all florets ligulate, perfect, golden-yellow, with
short tube and 5-toothed strap. Fruit an achene (technically a cypsela), 2–4 mm
long, drab or olive; pappus of numerous bristles, white, elongated, fused for
most of length and free above.
Parts
in Commerce:
Root with rhizome, or leaves harvested before flowering
Identification:
Roots
- Long slender taproots,
often branching
- 0.5–1.5 cm thick
when dried
- Outer surface
dark brown, longitudinally wrinkled (fresh root plump, often yellowish
brown)
- In cross-section
often irregularly shaped, with outer cork layer, alternating wide rings of
whitish parenchyma and thin brownish rings of latex-bearing vessels making
up most of the root, and a small yellowish cylinder of vascular tissue in
the center
- Rhizome portion
differs from root by presence of a small pith at the center of the
vascular tissue
- Fracture corky;
breaks easily
- Taste weakly
bitter, sometimes slightly sweetish
Leaves
- Oblanceolate,
sometimes approaching narrowly obovate; size variable
- Base tapering;
petiole short
- Apex obtuse
- Margins usually
with large irregular teeth at least on lower portion, rarely almost
entire; teeth triangular, several on each side, pointing backward or
straight out, often with smaller teeth on their margins
- Both surfaces
sparsely hairy to glabrous; hairs white, weak, short, mostly along veins
especially on upper surface
- Upper surface
dark green, lower surface paler; midrib and primary veins may be
purple-tinged
- Midrib
prominent; venation otherwise usually weak and inconspicuous, sometimes
raised on lower surface
- Primary veins
pinnate, often parallel to lower concave side of teeth; if apical portion
of leaf lacks teeth, primary veins usually somewhat forward-pointing and
anastomosing well inside margin
- Taste bitter
Adulterants: Former substitutes
for dandelion root include Cichorium intybus L. (Chicory, cf.),
dock (Rumex) species, lettuce (Lactuca) species, and Leontodon
hispidus L. (hawkbit). Numerous latex vessels are seen in roots of Cichorium,
but they are in rays extending outward from the center, rather than in rings.
Other features that may be found in incorrectly identified roots include:
- Yellow color
throughout
- Fracture very
hard and tough
- Vascular
cylinder containing radial rays of xylem separated by narrow medullary
rays
- Taste bitter
There are other species of Taraxacum that can
be difficult to distinguish from T. officinale, though they are rarely
reported to be substituted; whether this is because they are comparatively
uncommon or because substitution goes unnoticed is unknown.
Leaves of other
rosette-forming species such as Cichorium can be confused with those of Taraxacum
in the spring. The rosette leaves of Cichorium are often only shallowly
toothed for much or all of their length, sinuate-margined, or with many narrow
teeth projecting outward from a broad blade, whereas these conditions are
atypical though possible in Taraxacum. Their leaf apices are often
narrowly acute. Cichorium may be more strongly pubescent than Taraxacum,
with ciliate leaf margins and hairs growing densely along veins, but this is
not always the case.
References:
British Herbal Medicine Association.
British Herbal
Pharmacopoeia. BHMA; 1996:68–69.
Fernald ML. Gray’s Manual of Botany, 8th ed. New York: American Book
Company; 1950:1549–1553.
Richards AJ, Sell PD. Taraxacum. In: Tutin TG, Heywood VH, Burges NA, et al.,
eds. Flora Europaea. Vol. 4. Cambridge: Cambridge University
Press; 1976:332–343.
Youngken HW. Text-Book of Pharmacognosy, 5th ed. Philadelphia, PA: The
Blakiston Company; 1943:888–892.
Figure 74: Taraxacum officinale, cross-section of young root with limited
secondary growth.
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