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common dandelion, dandelion, pissenlit officinal, red seed dandelion

alpine dandelion, horned dandelion, pissenlit tuberculé

Habit Plants (1–)5–40(–60) cm; taproots seldom branched. Plants (1–)6–50 cm; taproots branched.
Stems

1–10+, erect or ascending, sometimes ± purplish (usually equaling or surpassing leaves), glabrous or sparsely villous, slightly more so distally.

1–10+, ascending to erect, ± purplish (at least proximally), densely villous (young) becoming glabrescent, sparsely villous to glabrate or glabrous proximally, ± densely villous distally.

Leaves

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).

± 10, horizontal to patent, sometimes erect;

sessile or petioles ± broadly winged (bases barely narrowed compared to blades);

blades narrowly oblanceolate to linear-oblanceolate or linear-oblong (often ± runcinate), 4–30 × (0.4–)0.5–5 cm, bases cuneate to attenuate, margins lobed ± deeply to lacerate, irregularly to regularly, often toothed, merely denticulate, or subentire, lobes retrorse, straight or antrorse, deltate to triangular, acute to acuminate, teeth 0–1 on lobes, often more or mostly in sinuses, apices obtuse to sometimes acute, sometimes mucronate, faces glabrous or glabrate to very sparsely villous.

Involucres

green to dark green or brownish green, tips dark gray or purplish, campanulate, 14–25 mm.

dark green, sometimes ± glaucous, campanulate to ± hemispheric, (5–)8–19(–21) mm.

Florets

40–100+;

corollas yellow (orange-yellow), 15–22 × 1.7–2 mm (outer).

40–85+;

corollas yellow, drying cream to whitish (outer abaxially gray or purple-striped on drying), 10–22 × 1–2.8 mm.

Phyllaries

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.

(10–)12–14(–17) in 2 series, lanceolate to ovate-lanceolate (inner), 1.5–4.5 mm wide, margins scarious or not (outer), inner broadly scarious in proximal 1/2, apices usually horned, occasionally hornless, horns sometimes exceeding apices, tips white to purplish, scarious, erose.

Calyculi

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 12–16(–20), appressed to spreading, pale, ovate to elliptic or lance-ovate to lanceolate (sometimes thin) bractlets in 2–3 series, 5–12 × (0.9–)1.5–5 mm, margins hyaline, white or purplish, scarious, apices caudate to acuminate, ± strongly horned, callous, or occasionally some (rarely all) hornless, tips obtuse to rounded, scarious, erose.

Cypselae

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.

olivaceous to olive brown, tan to olivaceous tan, brown to reddish brown, grayish brown or straw-colored, bodies oblanceoloid to obovoid, 2.5–4(–5) mm wide, cones conic or narrowly conic to broadly terete, 0.5–0.9 mm, beaks slender, 4.5–14 mm, ribs 5, large (bearing 10–15 narrower ones), faces proximally tuberculate or sometimes nearly smooth (usually with at least some tubercules) to muricate in distal 1/3–1/2, sometimes wholly muricate;

pappi white to cream, 5–7.5(–8) mm.

2n

= 24, 40, [16, 32].

= 16, [24], 32, 40, 48.

Taraxacum officinale

Taraxacum ceratophorum

Phenology Flowering nearly year-round (fall–spring, south; spring or summer, north). Flowering spring–summer.
Habitat Often damp low places, lawns, roadsides, waste grounds, disturbed banks and shores Wet to moist areas, calcareous or igneous rocks, gravel, sand, or clay, wet meadows, shores of streams, sandy or gravelly seashores, seepage slopes, early-melting snowbeds (south)
Elevation 0–2000+ m [0–6600+ ft] 0–3000 m [0–9800 ft]
Distribution
from FNA
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; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; SPM; Greenland; Europe [Introduced in North America; also introduced in Mexico; introduced nearly worldwide]
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; CO; MT; NM; NV; OR; UT; WA; WY; AB; BC; MB; NL; NT; NU; ON; QC; SK; YT; Greenland; Eurasia
[WildflowerSearch map]
[BONAP county map]
Discussion

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 ceratophorum is the most widespread native dandelion in North America, ranging from the low Arctic and boreal zone to the western Cordilleras, in the montane and alpine zones.

This complex has been subdivided into many microspecies in North America, most of which appear unworthy of recognition. In the Quebec-Labrador Peninsula, Taraxacum ceratophorum grades continuously into what has been called T. hyperboreum. Inclusion of T. hyperboreum bridges the gap between typical T. ceratophorum and T. lacerum. Taraxacum lacerum stands out by its very lacerate leaves, but intermediates exist and it is impossible to draw a firm boundary. The lacerate Newfoundland form, T. longii, may be a spontaneous mutation within the range of T. ceratophorum. If T. lacerum were recognized, we would have to place T. longii within the former based on leaf morphology, though leaf orientation would be odd there (T. lacerum tends to have ascending leaves, and T. longii leaves that are flatter on the substrate). A more thorough morphometric and biosystematic study of this complex is warranted. Nonetheless, I have recognized two segregates (T. laurentianum, T. trigonolobum) that stand out from the continuum otherwise observed in the complex.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 19, p. 244. FNA vol. 19, p. 247.
Parent taxa Asteraceae > tribe Cichorieae > Taraxacum Asteraceae > tribe Cichorieae > Taraxacum
Sibling taxa
T. alaskanum, T. californicum, T. carneocoloratum, T. ceratophorum, T. erythrospermum, T. holmenianum, T. hyparcticum, T. lapponicum, T. latilobum, T. laurentianum, T. palustre, T. phymatocarpum, T. scopulorum, T. trigonolobum
T. alaskanum, T. californicum, T. carneocoloratum, T. erythrospermum, T. holmenianum, T. hyparcticum, T. lapponicum, T. latilobum, T. laurentianum, T. officinale, T. palustre, T. phymatocarpum, T. scopulorum, T. trigonolobum
Synonyms Leontodon taraxacum, T. officinale var. palustre, T. sylvanicum Leontodon ceratophorus, T. ambigens var. fultius, T. angulatum, T. arctogenum, T. brachyceras, T. carthamopsis, T. coverum, T. dumetorum, T. eriophorum, T. eurylepium, T. groenlandicum, T. hyperboreum, T. integratiforme, T. integratum, T. lacerum, T. lateritium, T. longii, T. mackenziense, T. malteanum, T. maurolepium, T. microcerum, T. ovinum, T. pellianum, T. pseudonorvegicum, T. umbriniforme, T. umbrinum
Name authority F. H. Wiggers: Prim. Fl. Holsat., 56. (1780) (Ledebour) de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 146. (1838)
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