Taraxacum officinale
Taraxacum hyparcticum
common dandelion, dandelion, pissenlit officinal, red seed dandelion
high-arctic dandelion
1–10+, erect or ascending, sometimes ± purplish (usually equaling or surpassing leaves), glabrous or sparsely villous, slightly more so distally.
1–5, ascending to erect, pinkish to reddish or purplish, (barely exceeding foliage), glabrous or glabrate (rarely sparsely villous and villous distally).
20+, horizontal to erect;
petioles ± narrowly winged;
blades oblanceolate, oblong, or obovate (often runcinate), (4–)5–45 × (0.7–)1–10 cm, bases attenuate to narrowly cuneate, margins usually shallowly to deeply lobed to lacerate or toothed, lobes retrorse, broadly to narrowly triangular to nearly lanceolate, acute to long-acuminate, terminals ± as large as distal laterals, ultimate margins toothed or entire (secondary lobules irregular, perpendicular to retrorse), teeth minute to pronounced apices acute to acuminate or obtuse, faces glabrous or sparsely villous (commonly on midveins).
fewer than 10, usually patent, rarely erect;
petioles sometimes narrowly winged;
blades oblanceolate (often ± runcinate), 2–12+ × (0.3–)0.5–1.2 cm, bases attenuate, margins lobed deeply and regularly to denticulate or subentire, lobes 5–6 pairs, straight to retrorse, triangular to deltate, teeth triangular 0–1 on lobes or 1–4 shallow pairs if subentire, acute to ± obtuse, apices obtuse to ± acute, faces glabrous.
green to dark green or brownish green, tips dark gray or purplish, campanulate, 14–25 mm.
dark green to bluish black or dark purplish green, narrowly campanulate, 15–30 mm.
40–100+;
corollas yellow (orange-yellow), 15–22 × 1.7–2 mm (outer).
25–50;
corollas cream-colored to white or pink-tinged distally, outer pinkish-striped abaxially, 15–20 × 1.2–3 mm.
13–18 in 2 series, lanceolate, 2–2.8 mm wide, margins scarious (proximal 2/3) to narrowly scarious, apices acuminate, erose-scarious, usually hornless (seldom appendaged), callous.
8–14 in 2 series, lanceolate to lance-ovate, 1.5–3.5 mm wide, margins narrowly (outer) to widely scarious in proximal 1/3 (inner), narrowly so distally, apices long-acuminate, sometimes callous, hornless (rarely very small horns), tips white-scarious, erose, rounded.
of 12–18, reflexed, sometimes ± glaucous, lanceolate bractlets in 2 series, 6–12 × 2.8–3.5 mm, margins very narrowly white-scarious, sometimes villous-ciliate distally, apices acuminate, hornless.
of 10–14, spreading to appressed (thinner than phyllaries), dark green, broadly ovate or ovate to oblong bractlets in 2–3 series, 6–10 × 3.4–5 mm, margins narrowly hyaline, scarious, apices abruptly acuminate to caudate, strongly horned, tip ± scarious, erose.
olivaceous or olive-brown, or straw-colored to grayish, bodies oblanceoloid, (2–)2.5–2.8(–4) mm, cones shortly terete, 0.5–0.9 mm, beaks slender, 7–9 mm, ribs 4–12, sharp, faces proximally smooth to ± tuberculate, muricate in distal 1/3;
pappi white to sordid, 5–6(–8) mm.
tan or straw-colored to brown (or reddish brown), sometimes grayish, bodies obovoid to oblanceoloid, 3–3.7(–4) mm, mostly broad, cones conic, 0.4–0.7 mm, beaks slender, 3.5–4.5 mm, ribs 10–13 (5–6 prominent), mostly broad, faces proximally tuberculate, muricate in distal 1/2;
pappi whitish or sordid, 5–5.5(–7) mm.
= 24, 40, [16, 32].
= [24, 32, 40? some erroneous reports in literature under this name from Eurasia].
Taraxacum officinale
Taraxacum hyparcticum
Taraxacum officinale is the most widespread dandelion in temperate North America, though its abundance decreases in the arid south. It is a familiar weed of lawns and roadsides. It is also the species most commonly used for medicinal and culinary purposes (e.g., E. Small and P. M. Catling 1999).
Phenotypic and genotypic variation of this species have been studied in North America (L. M. King 1993; King and B. A. Schaal 1990; J. C. Lyman and N. C. Ellstrand 1998; O. T. Solbrig 1971; R. J. Taylor 1987), but results of those studies did not lead to the recognition of microspecies.
Specimens of Taraxacum officinale with deeply lobed leaves are sometimes difficult to distinguish from those of T. erythrospermum when fruits are missing (see also R. J. Taylor 1987). Usually, however, early leaves of the former are much less deeply lobed than those of the latter, which are more consistently lacerate throughout development, though broadly winged initially. The two taxa are easily distinguished in fruit, the red cypselae of T. erythrospermum standing out from the dull olive ones of T. officinale.
In northeastern North America, Taraxacum officinale and T. lapponicum often are confused, which has led to reports of the common dandelion farther north than I have been able to verify (it has yet to be collected from the Nunavik region of Quebec, for instance). The characters in the key above help separate the two taxa.
The typification by A. J. Richards (1985) would leave the common dandelion of both Europe and North America without a valid name (J. Kirschner and J. Štepánek 1987). For the time being, with the nomenclatural situation still not resolved, I am following traditional usage of the name Taraxacum officinale.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Taraxacum hyparcticum is sporadic in Arctic Eurasia (coastal Russia from Russian Far East west to Novaya Zemlya); it is mainly high-arctic. It is characterized by its small stature and large heads with white to yellowish cream ligules.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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