Not to be semantically confused with the genus :
Erysimum [plants with similar names belonging to the Cabbage Family (Brassicaceae) such as
Wallflower and Treacle Mustard]
Some similarities to : Sea-Holly (Eryngium maritimum) to which it is directly related.
Uniquely identifiable characteristics
Distinguishing Feature : Like Sea-Holly (Eryngium maritimum) but much smaller globular flower-heads, leaves spiny and pale-green with no hint of steel-blue on the plant anywhere.
Sea-hollies are atypical umbellifers where the umbel is not recognisable as such. It is very rare and should not be disturbed. Inhabits grassland and dry open places, mostly near the sea and especially on calcareous soils. Extremely localised occurring in very few places in the south of England, especially on the Roman road called Watling Street as it passes through Dartford, Kent, where presumably these photographs were taken by Dawn.
The roots were formerly boiled as a vegetable or candied to eat as sweets. But the plant is very rare now and it is illegal to uproot it. It was also used medicinally as, variously, an antitussive, diuretic, appetizer, stimulant and aphrodisiac and to treat coughs, whooping cough and urinary infections. It contains an essential oil plus saponins and tannins.
The major components of the essential oil are α-Pinene and the aldehyde
(Z)-3-Hexenal, the latter having an intense green odour of freshly cut grass and acts as an attracting pheromone to many insects. It is responsible for part of the aroma of
Apples and is used to flavour vegetable and fruity food and in perfumes.
The 3-(-D-Glucopyranosyl -OxyMethyl) glycosides of the triple methyl derivative of
CycloHexanone and of
CycloHexadienone , which are both monoterpene aldehydes. It is quite possible these two glycoside terpenoids are responsible for some of the taste and medicinal properties of Field Eryngo.
The saponins of Eryngium species consist mostly of the polyhydroxylated
Oleanene type of triterpenoid saponins.
For Field Eryngium these consist mainly of numerous differing glycosides of
Barrigenol derivatives. Shown is just one of the many triterpene steroidal Barringenol bases, A1-Barringenol. The saponins (glycosides of these) have two or three glycoside units and several other side groups.
Field Eryngo is also said to contain Agasyllin and Aegelinol, the latter being the Angelic Acid ester of the former. Unfortunately, there seem to be two competing formulae for the both, the one set linear FuroCoumarins, the other set Linear PyranoCoumarins. It could be that the one can turn into the other, but there are two hydrogens left over. Or it could be that the people who tried to identify them drew the wrong structural conclusions. Which is right is open to speculation. But your Author now favours the latter: pyranocoumarins. One source says there are both FuroCoumarins and PyranoCoumarins within Field Eryngo, but does not list them specifically.
One sources says that the roots contain the linear Furanocoumarins
Agasyllin which have anti-biotic properties. Like all furocoumarins, there is every reason to suspect that these furocoumarins are also photo-toxic, meaning that if the sap gets onto your skin and the skin is then exposed to the sunshine, an allergic reaction will be generated at that site, which could be very bad. Furocoumarins interfere with DNA putting a spanner in the works of all the cells exposed to it.
The flavonoids Astragalin, Rutin, IsoQuercitrin,
Quercitrin and Quercetin