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.