STINKING CHAMOMILE

Anthemis cotula

Daisy & Dandelion Family [Asteraceae]

month8jun month8june month8jul month8july month8aug month8sep month8sept

status
statusZarchaeophyte
 
flower
flower8white
 
inner
inner8yellow
 
morph
morph8actino
 
petals
petalsZMany petalsZ12
(~12)
stem
stem8round
 
stem
stem8fluted stem8ribbed
 
smell
smell8sickly
sickly
toxicity
toxicityZlowish
 
contact
contactZmedium
 

23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
Grows in arable fields as a weed, these in the margins of a field of Maize.


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
A spreading sprawling plant to 50cm.


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
Flowers like a large version of Daisy but with only ~12 petals ±1 (excluding those that have fallen off).


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
But the leaves are totally different from those of Daisy, being fine and wire-like.


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
Has white petals (actually ray-florets) and a large usually bulbous yellow dome of disc-florets. Stems ribbed/fluted, depending upon your point of reference.


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
Yellow disc-florets often highly domed, but otherwise truncated (flower behind). Text goes here


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
Typical 'shuttlecock' shape when not bedraggled by wind or rain, petals reflexed (many are not).


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
Disc-florets in close-up.


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
The bracts supporting the flower behind in a flattish saucer-shaped 'cup' (rather than a bowl of (just a few) similar flowers).


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
The supporting bracts are green down the centre-line, pale-green/white around the periphery, and brownish at the pointed ends (as are those of Scented Mayweed (Matricaria chamomilla) and Chamomile (Chamaemelum nobile). Text goes here


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
The leaves are fine, wire-like, much-branched and linear, and rather un-tidy. Text goes here


23rd Sept 2013, arable field, Pickmere, Cheshire. Photo: © RWD
There are said to be reflexed 'ligules' (tiny bits of flesh at the base of the leaves as they emerge from the nain stems). It is possible that the two wire-like projections seen in the photo are these ligules (well one can be seen, the other one presumably hidden by the stem).


Not to be semantically confused with the Genera : Cotula [which means 'cup' in Greek, and names the Buttonweeds group, which also belong to the same Daisy & Dandelion Family as does Anthemis cotula] nor with Chameleon (Houttuynia cordata) which belongs to the Chameleon Family (Saururaceae).

Easily mis-identified visually as :

  • other so-called 'Chamomiles' such as Chamomile (Chamomile mixtum) itself (which is scented and strongly aromatic)
  • Corn Chamomile (Anthemis arvensis) (which is scarcely scented)
  • Sicilian Chamomile (Anthemis punctata) (which grows mainly near the sea)
  • Austrian Chamomile (Anthemis austriaca) (which has neater more-regularly branched leaflets)
  • Yellow Chamomile (Anthemis arvensis) (but that has yellow 'ligules' - minute flaps at base of the leaves)
  • and other so-called 'Mayweeds' such as Scented Mayweed (Matricaria chamomilla) which is strongly sweetly scented when fresh.
  • Sea Mayweed (Tripleurospermum maritima) but that is shoter and more succulent and grows on shingle/sand beside the sea.
  • Scentless Mayweed (Tripleurospermum maritimun ssp. inodorum) which, although a sub-species of Sea Mayweed, is not succulent and lacks any smell when crushed.
But is easily distinguished from another 'Mayweed' Pineapple Weed (Matricaria discoides) which lacks ray florets (petals), possesses just a central yellow dome of yellow disc-florets, and smells of pineapples when crushed

However, Stinking Mayweed stinks, and thus is easily recognisable from all the above by means of this unique feature (for Mayweeds/Chamomiles) alone! Both Stinking Chamomile and Scentless Mayweed (Tripleurospermum maritimun ssp. inodorum) are much the more likely species to be seen in early Autumn.

Uniquely identifiable characteristics (for Mayweeds/Chamomiles)

Distinguishing Feature : it smells sickly/nauseous when crushed (rather than sweetly or aromatically).

It lacks a pappus ('seed-clock').

The plant smells nauseous when crushed, one of the most reliable identifying features. Stinking Chamomile is mildly toxic to livestock (and presumably humans too), not least because of the presence of polyacetylenes and sesquiterpene lactones. The aerial parts also contain two flavones, Apigenin and Hispidulin

POLYACETYLENES (POLYYNES)

It also contains several poisonous polyacetylenes (polyynes) all based upon DeHydroMatricaria Ester, which contains not just 2 triple bonds as Matricaria Ester, but three (hence the '8-dehydro' prefix). There are also three (only two of which are shown) methyl-thio derivatives of this, containing only 2 triple bonds. The shape of the molecules is shown only schematically, the Z- and E- bends are not depicted.

These polyynes occur in the roots of the plant and exhibit significant anti-mycobacterial action as well as allergenic activity.

ANTHECOTULIDES

The plant contains Anthecotulide, a non-volatile oil, is a sesquiterpene lactone known to be a potent contact allergen. It is present in the leaves at 1.5% and in the flowers at 7%. There are five more sequiterpene lactones present with similar, but not identical, side-chains. The extra side-chains are variously -OH groups or -O-CH3 groups. (Claims that this potent allergen is sometimes found in the essential oils nominally obtained from Chamomile is highly likely to be due to contamination of Chamomile collections with Stinking Mayweed; they look very similar in the field).


The 5,6-epoxide of Anthecotulide is also present, and one assumes it is more potent that Anthecotulide itself.

An ACETOPHENONE and a related CHROMANOME

These compounds are common in members of the Dandelion & Daisy family and are present in the aerial parts of Anthemis species, which includes Stinking chamomile.

IsopentylAcetophenones and Benzopyrones (chromenes) like both the above exhibit growth-inhibitory and anti-inflammatory activity in yellow mealworm larvae. Prenylated Acetophenones may also have phytoalexin activity; anti-micromial compounds that accumulate in plants when under stress such as by infection. It is possible that their detection in Stinking Chamomile is as a result of such an infection, and that they are not normally present (but when are plants under no threat from infection?).


  Anthemis cotula  ⇐ Global Aspect ⇒ Asteraceae  

Distribution
 family8Daisy & Dandelion family8Asteraceae

 BSBI maps
genus8Anthemis
Anthemis
(Chamomiles)

STINKING CHAMOMILE

Anthemis cotula

Daisy & Dandelion Family [Asteraceae]