Tanacetum vulgare

Daisy & Dandelion Family [Asteraceae]  

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Pappus: pappusZpossible (if present, tiny)
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petalsZ0 petalsZmany
smell8aromatic smell8camphor smell8rosemary

27th July 2012, Marine Lake, Southport. Photo: © RWD
Tall, stout with dark-green foliage growing to 1.2m high. Despite its appearance here near water, it does not especially grow near water, it is more often found in bare, grassy rough ground and waysides.

5th Oct 2005, Jacksons Bridge, River Mersey. Photo: © RWD
Usually clumped together in large clusters.

13th Aug 2007, Chesterfield Canal. Photo: © RWD
Grows erect.

27th July 2012, Marine Lake, Southport. Photo: © RWD
With alternate fern-like leaves.

13th Aug 2007, Chesterfield Canal. Photo: © RWD
Leaves pinnate.

15th Aug 2014, Sefton Coast. Photo: © RWD
Inflorescence a flat-topped dense corymbe (which is similar to a simple umbel, but the flower stalks do not radiate from one point as they do in an umbel).

15th Aug 2014, Sefton Coast. Photo: © RWD
Flowers entirely discoidal or button-like, about 6-10mm across, consisting entirely of disc-florets. Style slightly darker yellow, and slightly longer than the disc florets from which they poke out of some disc florets. Only very rarely are ray-floret specimens encountered; your Author has never seen one.

12th Aug 2005, Leeds & Liverpool Canal, Aintree. Photo: © RWD
From above they have a slight depression in the centre.

5th Oct 2005, Jacksons Bridge, River Mersey. Photo: © RWD
Disc florets smaller in the centre, getting wider towards the periphery as they mature. Displaying the classical  Fibonacci spiral, two counter-rotating  Logarithmic Spirals.

5th Oct 2005, Jacksons Bridge, River Mersey. Photo: © RWD

27th July 2012, Marine Lake, Southport. Photo: © RWD
The outer florets have opened slightly revealing the 5 inwardly-directed triangular lobes of the disc-florets. In the centre lurks the darker-yellow style getting ready to poke slightly out from the disc floret.

Photo: © RWD
The two sets of unopened flowers in the top right and bottom left corners are not as advanced as those unopened flowers in the centre.

Photo: © RWD
Firmly wrapped in the bracts which later occupy the underneath of the flower as that expands more.

15th Aug 2014, Sefton Coast. Photo: © RWD
Beneath opened flowers are several alternately-overlapping whorls of bracts or sepal teeth.

21st May 2012, near coast, Southport. Photo: © RWD
Leaves singly-pinnate.

27th July 2012, Marine Lake, Southport. Photo: © RWD
Upper surface of leaf. Leaves with many lobes.

27th July 2012, Marine Lake, Southport. Photo: © RWD
Lower surface with keeled mid-rib.

30th April 2012, near coast, Southport. Photo: © RWD
Each leaf lobe may have a few pointed teeth.

30th April 2012, near coast, Southport. Photo: © RWD
Irregular pointed teeth on leaf lobes.

30th April 2012, near coast, Southport. Photo: © RWD
Main stem.

No relation to : Tansy-Leaved Phacelia (Phacelia tanacetifolia) [a flower belonging to a differing family].

In addition there does exist a Rayed Tansy (Tanacetum macrophyllum) which has slightly larger yellow flowers with rays (7-13mm across) and of similar height (1.2m) but which is much less common occurring mainly in northern England and Scotland.

A much commoner flower belonging to the same genus (Tanacetum) is Feverfew (Tanacetum parthenium) but that is much shorter at only 70cm high and has much larger flowers (15-23mm across) which have white rayed florets with yellow disc-florets in the centre, the leaves are also very different. This too, like Tansy, is strongly aromatic.

Uniquely identifiable characteristics

Used to be called: Chrysanthemum Vulgare.

Tansy spreads by underground stolons.

The leaves are bitter and spicy and once used to make Tansy (a custard pudding), but it may be poisonous if taken internally. Indeed, both Ragwort and Tansy contain Pyrrolizidine Alkaloids which are moderately poisonous. Ingesting excess Tansy can cause permanent liver damage, digestive disturbances, lack of coordination, weakness, staggering, and death. Cattle are only vulnerable when Tansy is present as an unwanted inclusion within the hay or when wilted, for otherwise they don't usually touch it. The toxins within are not destroyed on storage or drying. It can contaminate milk and honey. Gloves should be worn if up-rooting Tansy by hand, for the alkaloids present, including Tanacetin, are readily absorbed through the skin.

Tansy is a member of the Daisy & Dandelion family, but un-like most members, possesses no ray florets, only central disc florets. In America it spreads readily and is a controlled weed.

The stem leaves are very similar to those of Leptinella (Cotula squalida) but the flowers of Leptinella are in singles atop a stalk which is very much shorter than that of Tansy. Also, the flowers, although both are yellow and both are lacking ray-florets, are very much less compacted than those of Tansy.

Traditionally, Tansy was used for treating tapeworm, roundworm and threadworm and as a stimulant for migraine, loss of appetite and liver problems. Sprigs of Tansy were placed in the house to keep flies at bay. The flower heads yield commercial insecticides, (Pyrethrin I and Pyrethrin II) and were once used to treat lice.

Large consumption of Tansy can be fatal, due mainly to Thujone in the essential oil. Symptoms of poisoning include abdominal pains, serious gastroenteritis, convulsions, tachycardia, arrhythmia, liver and kidney damage, loss of consciousness and finally death.

Possessing natural insecticidal properties Tansy was sometimes planted (or allowed to grow) near or within crop plants on farmland in order to keep pests at bay without recourse to modern insecticides (which may not have been as effective in past times).

A yellow dye can be extracted from the flowers.

Tansy contains the allergenic Sesquiterpene Lactone, Arbusculin A, which may be an effective treatment for Lymphoid Leukaemia. Because of this toxic substance, Tansy can induce contact hypersensitivity as can other similar sesquiterpene lactones found in many other flower genera.

Senecionine is also present.

Tansy also contains other sesquiterpene lactones such as Tanacetin and Tanacetol A.

Thujone is another constituent of Tansy. Note the strained three-membered carbon ring of cyclopropane, the instability of which (cleavage of the ring) probably significantly contributes to the toxicity of Thujone. It has the odour of a similar but not identical compound called Menthol, which is responsible for the aroma and taste of some Mints. Junipers, Mugwort, Wormwood (from which the alcoholic beverage absinthe is made) and common sage also contain some thujone. Thujone has only a minute presence in the absinthe. It is moderately toxic and acts on some neurotransmitter receptors within the brain and is thus a neurotoxin too. The toxicity of Tansy is mainly due to the presence of β-Thujone in the essential oil, amongst Camphor and other mono-terpenoids.

Senecionine (aka Aureine and Squalidine) is a pyrrolizidine alkaloid which is hepatotoxic, damaging the liver on ingestion, and found in Tansy and also in species of Senecio [in the Daisy Family] (which includes Ragworts such as Oxford Ragwort, Groundsels) and species of Crotalaria (a member of the Pea Family) which grows in the tropics. Senecionine has uses in the biological laboratory.

Tansy also contains camphene and Myrtenol, or oil of myrtle, a constituent of Bog Myrtle. These substances contribute to Tansy being an effective insect repellent and insecticide.

Camphene is an aromatic hydrocarbon and bicyclic monoterpene which has a faint smell reminiscent of Camphor. Virtually insoluble in water it is present in turpentine oil, nutmeg, lemon, juniper berries, bergamot oil, cinnamon oil, camphor oil, citronella oil, ginger oil, neroli, cypress oil and Valerian. It is used in fragrances and somewhat strangely as a food additive for flavouring. Like camphor, it tends to sublime (slowly evaporates without melting).

Some books confuse Tanacetol with Thujone (shown above), equating the two, but as can be seen here, they are quite different. The active moieties in Tanacetol A are on the oxygen atoms, of which there are four.

Germacrene D is one of the essential oils that are typically accompanied by Cadinane and Muurolene sesquiterpenoids, which are similar in chemical structure to Germacrene but with variations; a consistent variation being the bond joining the two rings. Germacrenes are typically produced in a number of plant species specifically for their insecticidal and anti-microbial properties, which the plant uses in defence. Therefore it is somewhat counter-intuitive that they are also extant in playing a role as insect pheromones, attracting the very insects they are trying to poison; perhaps in an effort to kill as many as possible(?). But perhaps it instead repels unwanted species of insects whilst attracting others for pollination duties which the insects unknowingly perform as they suck up any nectar from the flowers?

Tansy also produces sterols β-Sitosterol), terpenoids (α-Amyrin and β-Amyrin).

  Tanacetum vulgare  ⇐ Global Aspect ⇒ Asteraceae  

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Tanacetum vulgare

Daisy & Dandelion Family [Asteraceae]  

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