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, 8^th 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, 5^th ed. Philadelphia, PA: The Blakiston Company; 1943:888–892.

Figure 74: Taraxacum officinale, cross-section of young root with limited secondary growth.