Dandelion

Taraxacum officinale ex Weber ex Wigg. s. lat.

Synonyms - Taraxacum dens-leonis.

Family: Asteraceae.

Names:

Taraxacum from the Latin tarasacon.
Officinale is medieval Latin meaning belonging to an officina or monastry store room where medicines were kept and is now applied to plants (or other organisms) that had an established herbal, medical, culinary or other use.
Officinale
Dandelion means lion's teeth referring to lion tooth like 'petals'.

Other Names:

Common Dandelion
English Dandelion
European Dandelion
True Dandelion

Summary:

A rosette forming, biennial or perennial plant with backward pointing lobes on its leaves and single bright yellow daisy-like flowers on long stalks and milky sap.

Description:

Cotyledons:

Two. Oval, 7-12 mm long overall with a short merging petiole, and rounded tip. The edges are often slightly undulating. Base tapered. Hairless. The seedling has a very short hypocotyl and no epicotyl.

First leaves:

Arise singly, are 10 to 20 mm long overall with a usually short but distinct petiole. They are hairless and have a dark green shiny surface. Tip pointed. Base tapered. Initially leaves have only a few small lobes or backward pointing teeth but as the plant develops the leaves they become progressively more lobed and in later rosette leaves may be secondarily divided. The third and older leaves exude a white sap when damaged.

Leaves:

All leaves are in the basal rosette. When cut they exude a white latex.
Stipules - None.
Petiole - Yes.
Blade - 30-300 mm long, thin and flexible, spear shaped and usually lobed, lobes are more or less regular and triangular with a larger end lobe and backwardly directed side lobes. Edges of lobes are irregularly toothed. Base is narrowed, often reddish, and sometimes slightly winged. Hairless or with a few, short, multi-cellular hairs on the upper and lower surfaces.

Stems:

None.
Flower stem - Scape - Unbranched, hollow, circular in cross section and 50-300 mm long. Hairless or a few thin downy hairs, which tend to be more numerous towards the top. Exudes a white latex when damaged.

Flower head:

Single on ends of leafless stalks (scapes) that are as long or longer than the leaves and arising from the centre of the rosette. Flower base (involucre) oblong, 15-20 mm long, with 1 row of inner bracts and several rows of outer bracts. Flower head looks like a fluffy ball just before the seeds blow away.

Flowers:

Yellow, 20-60 mm in diameter.
Bracts - Dark green with pale edges, 15-30, not horned. Inner ones narrowly egg shaped, initially erect and often bending back with age, parallel sided to narrowly egg shaped, tips narrowed and flat or pointed on top, tiny hairs on the back and edges. Outer ones shorter, to 10 mm long and spreading, narrowly egg shaped, hairy.
Florets - Many, all with 'petals' (ligules), edge ones often sterile, all bisexual.
Ovary - Receptacle naked, pitted. Style branches long and slender, obtuse tipped with long hairs.
'Petals' - Golden yellow, narrowly egg shaped.
Stamens -
Anthers - Arrow shaped.

Fruit:

Greyish or reddish, slightly flattened, narrowly to broadly egg shaped, striped, ribbed achene, 2.8-4.5 mm long x 0.8-1 mm wide, with tiny spines towards the top. The beak is a needle like column, 2-3 times longer than the achene with slender barbed bristles, with a pappus on top. Narrow, conic cusp below the beak. Pappus of many, simple, different length, creamy white, silky bristles in several rows.

Seeds:

Brown, distinctly ribbed with a toothed surface. The seed is 3-6 mm long x 1 mm wide and has a 10-12 mm long stalk carrying its 4-6 mm long hairy pappus.

Roots:

Thick, bitter, perennial rootstock.

Key Characters:

Stemless.
Milky latex.
Leaves all radical, pinnatifid or runcinate-pinnatifid, margins irregularly denticulate,
Heads solitary, scapose, many flowered.
Peduncle (scape) leafless, hollow.
Involucre ovoid, outer involucre bracts reflexed.
Florets all ligulate.
Receptacle naked.
Achenes sub cylindrical, oblanceolate, striate and muricate-spinulose in the upper half, rough towards the summit, long slender beak
Pappus bristles numerous and capillary.
Adapted from J.M. Black, N.T. Burbidge and N.S. Lander.

Biology:

Life cycle:

Biennial or perennial. Seeds germinate in autumn and to a lesser extent in spring. It grows mainly in the warmer months.

Physiology:

Reproduction:

By seed and perennial rootstock.

Flowering times:

Spring in western NSW.
Most of the year in SA.
Irregularly through the year in Perth.

Seed Biology and Germination:

Vegetative Propagules:

Perennial rootstock.

Hybrids:

Many subspecies. Plants within a locality are often very similar but are often quite distinct from those elsewhere.

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed.

Origin and History:

Europe. Asia.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.
Occurs in all parts of Tasmania.

Courtesy Australia’s Virtual Herbarium.

Habitats:

Climate:

Temperate. Mediterranean.
More abundant in the cooler, higher rainfall areas.

Soil:

Many soil types.

Plant Associations:

Significance:

Beneficial:

Honey plant.
Leaves bitter but edible as a salad vegetable. Roasted roots are ground and used as a coffee substitute.
Does not host Root Lesion Nematodes (Pratylenchus neglectus or thornei)

Detrimental:

Weed of lawns, crops, cultivation, pastures, roadsides and disturbed areas.
Serious weed of turf.

Toxicity:

Suspected of causing hay fever.

Legislation:

None.

Management and Control:

Thresholds:

Eradication strategies:

Difficult to eradicate once established.
Manually remove isolated plants.
Treat small infestations with a mixture of 500 mL of Lontrel plus 1 L of Tordon® 75-D plus 250 mL of Pulse® Penetrant in 100 L of water. Spray until just wet in late winter each year.

Herbicide resistance:

Biological Control:

Related plants:

Dandelion (Taraxacum erythrospermum)
Russian Dandelion (Taraxacum kok-saghyz).

Plants of similar appearance:

Dandelion is similar in appearance to both Cat's Ear and Hawkbit. The rosettes are distinguished from these two species by the relative lack of hairs on the leaves and by the more regular and backward directed lobes. The leaf is thin and of a flexible texture, unlike the hard brittle texture of Cat's Ear. The flower stem being hollow, is unlike that of the other two species where it is solid. In the seedling the leaves are relatively broader, more flexible in texture, and more regularly lobed, the lobes being more distinctly backward directed than the other two species. The leaves have a more clearly defined petiole. The name Dandelion is commonly misapplied to both Cat's Ear and Hawkbit.
Capeweed (Arctotheca calendula) has a light underside and darker upper surface on the leaf.
Flatweed (Hypochoeris radicata) is similar but has hairier, thicker, less flexible leaves, less regular lobes that are not generally backward pointing, the petiole is less distinct and the flowering stalks are solid and often branch to bear more than one flower.
Fleabane (Conyza spp.) don’t have obvious ‘petals’ and has leaves on the stem.
Hawkbit(Leontodon taraxacoides) is similar but has hairier, thicker, less flexible leaves, less regular lobes that are not generally backward pointing, the petiole is less distinct and the flowering stalks are solid.
Indian Hedge Mustard (Sisymbrium orientale)
Ox tongue (Helminthotheca echioides)
Prickly Lettuce (Lactuca serriola)
Prickly Sow Thistle (Sonchus asper)
Rapistrum (Rapistrum rugosum)
Slender Thistle (Carduus spp.)
Smooth Catsear (Hypochoeris glabra) is similar but has thicker, less flexible leaves, less regular lobes that are not generally backward pointing, the petiole is less distinct and the flowering stalks are solid and often branch to bear more than one flower.
Skeleton Weed (Chondrilla juncea) has backward pointing leaf lobes.
Sow Thistle (Sonchus oleracea)
Wild Radish (Raphanus raphanistrum)
Wild Turnip (Brassica tournefortii)

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P118. Photos.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P941. Diagram.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P396, 399. Diagram.

Cunningham, G.M., Mulham, W.E., Milthorpe`, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P715. Photo.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P106-107. Photo.

Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P38-39. Diagrams.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #1190.3.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P708.

McBarron, E.J. (1983). Poisonous plants. (Inkata Press, Melbourne). P56. Diagram.

Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P62. Diagrams. Photos.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.