PINEAPPLE WEED

Matricaria discoidea

Daisy & Dandelion Family [Asteraceae]  

month8may month8jun month8june month8jul month8july month8aug month8sep month8sept month8oct month8nov

status
statusZalien
 
flower
flower8yellow
 
inner
inner8green
 
petals
petalsZ0
discs
stem
stem8round
 
smell
smell8pineapple spell8apple
pineapple

15th July 2009, Arable Fields, Nr Martin Mere, Lancs. Photo: © RWD
Very weedy, tolerates much trampling and light traffic.


15th July 2009, Arable Fields, Nr Martin Mere, Lancs. Photo: © RWD
Proliferates if given half a chance.


27th July 2007, Hall Road, Merseyside. Photo: © RWD
Favours cracks in pavements, cobbles and stony ground. Endures significant abuse.


16th June 2009, Promenade, Colwyn Bay, North Wales. Photo: © RWD
Each plant has several branched main stems, upon which stubby flower heads without petals grow. The leaves are filigree-like threads.


30th July 2007, Huddersfield Narrow Canal, Slaithwaite. Photo: © RWD
The flowers, devoid of petals and ray florets, consist of a mass of yellowish-green disc-florets acorn-like in shape. The leaves are a profusion of fine flattish needles.


10th July 2009, Rosthwaite, Borrowdale, Lake Dist. Photo: © RWD
If crushed, the pineapple-like flowers smell distinctly of pineapple, hence the common name.


30th July 2007, Huddersfield Narrow Canal, Slaithwaite. Photo: © RWD
The disc-florets are yellowish-green and raised into a rather-pointed dome shape. The leaves multiply branched, flattish thin and pointed.


10th July 2009, Rosthwaite, Borrowdale, Lake Dist. Photo: © RWD
Many green sepals crowd the underside of the flower head.


10th July 2009, Rosthwaite, Borrowdale, Lake Dist. Photo: © RWD
Leaves many-branched, fine and filigree-like.


10th July 2009, Rosthwaite, Borrowdale, Lake Dist. Photo: © RWD
Flattish leaves, pointed and perhaps discolouring at the tip.


FASCIATION

 Mutations Menu

24th May 2016, Leicestershire. Photo: © Richard Mabbutt
Two flowers of one plant have here been fasciated, where the growing centre elongates. It is quite common in many Asteraceae plants, as well as in some other flower Families. In the longest there head is possibly composed of 5 or 6 'fused' single flower-heads (you can see the faint dips delineating each). The other fasciated head to the left seems to have but 2 (albeit asymmetric) fused flowerheads. All the others are singles.


Uniquely identifiable characteristics.

Distinguishing Feature : Has no petals (ray-florets) but a domed yellowish-green flower-head consisting of only disc-florets, and which smell of pineapple when crushed.

No relation to : Pineapple, a tropical fruit.

Pineapple Weed belongs to the Mayweed Genus Matricaria, so named because of its historical use against feminine gynaecological disorders (Latin: matrix - uterus). It is ubiquitous throughout the UK, growing on bare or disturbed ground and well-trodden places almost everywhere. Seems to enjoy growing in cracks in pavements, and may even grow through thin tarmac.

Unlike most flowers, it is bereft of petals, but does have a profusion of yellowish-green disc-florets in a domed slightly tapering head. The dried flowers can be used as a tea.


The main components of the essential oil extracted from Pineapple Weed are 28% Myrcene, 23% β-Farnesene, 7% Geranyl Isovalerate, 7% Germacrene D and 8% (Z)-en-yne-dicycloether. The first three are odorous compounds. Traces of the coumarin 7-methoxy-coumarin Herniarin were also found.

Geranyl Isovalerate is also found in species of Eucalyptus and smells of rose with an apple/pineapple undertone and tastes of sweet apple or apricot.

A POLYACETYLENE (POLYYNE)


Z)-en-yn-dicycloether is a di-cyclo-ether, rather than the often reported bi-cycloether - the latter would imply two fused rings - which is not the case since it is a spiro-ether. It has attached to it a hydrocarbon chain containing two triple bonds, the polyacetylene part. The highest concentration is contained in the leaves.


  Matricaria discoidea  ⇐ Global Aspect ⇒ Asteraceae  

Distribution
 family8Compositae family8Daisy family8Dandelion family8Asteraceae

 BSBI maps
genus8Matricaria
Matricaria
(Mayweeds)

PINEAPPLE WEED

Matricaria discoidea

Daisy & Dandelion Family [Asteraceae]  

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