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.
Of the Neophytes, Pineappleweed occupies the most hectads in the British Isles: 3530 out of 3795. However, it occurs in less that 50% of the 1km squares. This is according to Stace and Crawley in their book on Alien plants in the New Naturalist series.
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.