BLUE ERYNGO

Eryngium planum

Carrot Family [Apiaceae]

month8jul month8july month8aug month8sep month8sept

status
statusZneophyte
 
flower
flower8blue
 
inner
inner8azure
 
petals
petalsZ5
 
type
typeZglobed
ovoid
type
typeZclustered
 
type
typeZtubular
 
stem
stem8round
 
stem
stem8ribbed
 
stem
stem8spines stem8thorns
spines
contact
contactZlowish
 

7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
Grows up to 1m high with blue flowers, this specimen was planted besides the purple-topped Argentinian Vervain with what looks like an un-planted 'weed' behind: Mugwort.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
The flowers are blue and tall-domed in shape. The leaves at the base and on the lower parts of the stem are both distinctive and definitive.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
The stems are well-branched bearing candelabras of flat-based blue flowers in elongated domes.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
Still developing flowers are green rather than deep-blue. The stem leaves near the summit are very deeply lobed and spiny. The stems have a half-greyish appearance being brownish or greenish underneath the greyness.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
starting off pale green the flowers progress through azure and steely blue to a bright blue.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
The rayed bracts just below each flowerhead are planar (commensurate with the specific epithet of the Binomial name) and narrow linear-lanceolate with few short spines on the edges. The upper stem leaves are similar but wider, often around stem junctions of which there are many. These flowers are not yet fully developed, and therefore pale-green rather than bright blue.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
A stem as sinuous as the River Churnet (part of the Caldon Canal) when steering a 70' narrowboat along at breakneck speeds (well, as fast as it will go when continuously turning sharp corners). Stems lower down only slightly ribbed.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
Long narrow shaped bracts just below the flowers, slightly wider leaves around stem junctions amd also just on the stem itself without a junction. Both sparsely spiny.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
Immature flowerhead at top, younger and greener one below.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
The flower stalks can be grooved; much less so the main stems. The bracts can have a residual blue wash giving it a steely blue colour with the pale-green undertone. Each floret in a tight ring of 5 surrounds two slightly longer white styles, reminiscent of disc florets in the Daisy & Dandelion Family family, but this plant belongs to the Umbellifer (Apiaceae) family, albeit an atypical member of the Umbellifer family. The flowers do not seem to be in either a simple umbel nor a compound umbel but rather more like a number of tubular florets growing out of a central tapering column. Each floret can have 5 upright long tapering petals which are eventually bright blue in this case. But it seems more complicated than that looking at this (helpfully unlabelled!!) image found on Wikipaedia (which applies to Sea-Holly (Eryngium maritimum specifically, but other Eryngium species should be similar):  Eryngium maritimum. The flowers look as though they are bisexual (fig. 2) with 5 pointed bracts, with an inner-ring of shorter bilobed petals surrounding several shorter stamens and two longer styles. It seems each floret is composed of two internal 'halves' one (Fig.5) with 3 petals and 1 style) and another (un-shown?) with only 2 petals and one style?). If only the drawings were ever annotated on wikipaedias half-drawings...


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
Immediately alongside but at the earth side of each floret is a sharp(!) triple-pointed bract with white spines protruding about the same distance as the styles (best seen in the lower half of the flowerhead). The 5 bracts surrounding the floret are also pointed and white. When fully open it is difficult to differentiate between the slightly longer white styles and all these white pointed tips on the bracts.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
The florets are becoming bluer. Two white styles extend from each floret.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
The lower stem leaves have broad (winged?) stems broadly attached to the stem, some on very short stems and are D-shaped (or elongated D-shaped) like old shovels but with ragged and wavy edges.


7th July 2017, a walled garden, Waterloo, Sefton Coast. Photo: © RWD
The leaves at the base are extended-ovate and cordate (heart-shaped) at the base. Wow: even the stems are bright blue-purple near the ground! Your Author must endeavour to find out the pigment responsible for this coloration.


Some similarities to : Tall Eryngo (Eringium giganteum) which at 1.2m high is slightly taller but has upper stem leaves which are toothed or lobed only to less than half-way to the base and flowerheads which are grey or bluish (not a striking deep blue as per Blue Eryngo).

Slight resemblance to : Sea-Holly (Eryngium maritimum) but that is far shorter, grows on sand-dunes or shingle near the sea and although it too has bluish flowerheads, they are more steel-blue as are the very broad and deeply-cut bracts beneath each flowerhead and the stem leaves.

Blue Eryngo contains various secondary metabolites such as Phenolic Acids, triterpenoid Saponins, Flavonoids (from which it is claimed the blueness is due, although most flavonoids are yellow with only a few being red or blue - but another source says the blueness is due to Anthocyanins. Can they both be right? Your Author needs a list of actual pigments found!), Coumarins and essential oils. The polyyne (aka polyacetylene) (Z)-Falcarinol is a major but poisonous constituent of the essential oil in the root.

The essential oil obtained from the inflorescence contains 45% cis-Chrysanthenyl Acetate, the stalk leaves Limonene (14.7%) and β-Pinene (9.8%), the leaves in the basal rosette Bornyl Acetate (18.1%), Limonene (11.3%) and Terpinen-4-ol (10.9%, and the roots Falcarinol (64.4%) plus smaller quantities of 2,3,4-TriMethylBenzaldehyde.

It also contains Phenolic Acids, Carotenoids, Alkaloids, Polyphenols, Monoterpenoids, Sesquiterpenoids, TriTerpenoid Saponins, Flavonoids and Coumarins.

Due to some of these disparate compounds the plant exhibits multidirectional pharmacological activity with diuretic, expectorant, spasmolytic, antitussive, antifungal and stimulant properties.

ISOPHORONE


IsoPhorone is contained in Blue Eryngo but is not one of its main constituents. Nevertheless it is interesting as it is a monoterpenoid which smells similar to peppermint but when in aqueous solution and exposed to UV light (such as from the Sun) it undergoes dimerisation to produce three slightly different isomers, the Head to Tail dimer (HT) and the Head to Head (HH) dimer.


The proportion of the HH dimer increases as the acidity of the water is increased. The HT dimer is produced in two stereometric isomers (not shown), where the diametrically opposite hydrogen atoms on the cyclobutane moiety are both arranged in the same plane or are arranged in opposite planes.


  Eryngium planum  ⇐ Global Aspect ⇒ Apiaceae  

Distribution
 family8Carrot family8Apiaceae

 BSBI maps
genus8Eryngium
Eryngium
(Sea-Hollies)

BLUE ERYNGO

Eryngium planum

Carrot Family [Apiaceae]