Easily confused semantically with : Buttonweed [a plant of similar name belonging to the same Daisy & Dandelion Family but which looks more like a Colt's-foot plant but one curiously lacking ray-florets]. Nor should it be confused with Cotton Thistle, a thistle covered in longer white hairs.
Some similarities to :
Lavender-cotton, another member of the Daisy & Dandelion Family, but that is a low shrub, which also has deep yellow and ray-less flowers, is covered in a dense short matt of white hairs, and where the short pinnately-lobed leaves sparsely populate the stems allowing them to be seen.
Slight resemblance to : the
Cudweeds such as
Jersey Cudweed which are also covered in a dense matt of white hairs. They too belong to the same Daisy & Dandelion Family.
No relation to:
Black Cottonwood, a type of
Not to be semantically confused with : Buttonweed (Cotula coronopifolia) [which has a similar sounding name and belongs to the same Dandelion & Daisy Family (Asteraceae)]
Uniquely identifiable characteristics
Distinguishing Feature :
Rare! A salt-tolerant plant previously found in up to 20 scattered locations near the sea in the South of England and Ireland, but since the start of the new Century now found in only one location: in County Wexford, Ireland, by the sea.
It contains three
Piperidine Amides which exhibit insecticidal activity but they have long chemical names which lack common names. It also contains the dimer
PinoResinol plus three other compounds for which your Author can find no chemical structural formula:
Espletone. It also contains the
Aureonitolic Acid which again your Author has failed to find any chemical structural formulae and several terpenoids
Filifolone cis-Chrysanthenyl Acetate and
Chrysanthenone for which he can.
The cis- version of Chrysanthenyl Acetate, a monoterpenoid, is found in Cottonweed
Chrysanthenone, which is very similar, is also found. An isomer of Chrysanthenone is Verbenone, but this has not reportedly been found in the plant, but is found in similar plants.
Verbenone has a pleasant aroma and acts as an insect repellent in some trees and plants. It is used in aromatherapy and in perfumes, spices, herbal teas and, in the L-isomeric form, as a cough suppressant and expectorant under the medical name of Levoverbenone.
Filifolone is also found in Cottonweed. Note that Chrysanthenone has a 4-membered ring conjoined to a 6-membered ring, whereas Filifolone is almost identical but with the 4-membered ring conjoined onto a 5-membered ring. It therefore has one CH2 less than does Chrysanthenone.
LIGNINS and LIGNOLS
PinoResinol is the dimer of Coniferyl Alcohol, although the 5-membered ring of PinoResinol has been broken. PinoResinol is a lignan found in a few other plants too such as
Olive (Olea europaea) (and in Olive Oil), in some Forsythia and Pieris species, in Sesame seeds, in Brassica vegetables and frequently in woody resinous plants such as Styrax trees. It has two fused
Furan rings in the centre which are formed by the closure of the HydroxyPropenol moiety in Coniferyl Alcohol as part of the dimerisation process. PinoResinol is found in the Cabbage White butterfly (probably from the cabbages it consumes) where it acts as a defence chemical against ant attack.
Coniferyl Alcohol is a PhenylPropanoid MonoLignol to be found in both Angiosperm and Gymnosperm plants, including Cottonwed where some gets converted to PinoResinol in a dimerisation process. It polymerises forming lignans and lignin, one of which is PinoResinol, but other non-symmetrical dimers and polymers are possible. That is, unless the plant has an enantiocomplementary dirigent protenin, in which case polymerisation is directed towards PinoResinol whilst other dimers are suppressed. Thale Cress (Arabidopsis thaliana) has such a dirigent protein and contains Coniferol Alcohol which is converted to PinoResinol directed by this protein. This dirigent protein was first discovered in Forstythia x intermedia, the popular garden shrub, which also contains PinoResinol.