A blue form also exists as a morph.
Unlike the round stems of Bog Pimpernel, Scarlet Pimpernel has square stems, as does the similar, but un-related, Creeping Jenny.
Not to be confused with: 'Poor Man's Asparagus' [a plant with similar nickname].
CUCURBATICINS & their GLYCOSIDES, ARVENINS
All parts of Scarlet Pimpernel are poisonous, containing the Cucurbitacins, Arvenin I, Arvenin II, Arvenin III and Arvenin IV and
Cucurbitacin B as well as triterpene saponins and oxalates. All Arvenins are glucopyranosides. Cucurbaticins bind to microtubules and are therefore cytotoxic. All parts of the plant are poisonous, especially the roots, and consumption of it can result in gastrointestinal disturbances, trembling and kidney damage.
Related to the Cucurbaticins (of which Cucurbaticin B is just one) are the Arvenins, of which four are know, Arvenin I, Arvenin II, Arvenin III and Arvenin IV. Shown is just one, Arvenin I. Arvenin I is just Cucurbaticin B with a glycoside attached. The same poisons are also in White Bryony.
It also contains Cyclamin, a toxic monodesmosidic triterpenoid saponin which was first identified in species of
Cyclamen. The glycoside groups are depicted in blue. Cyclamin is a breakdown product of the Cucurbaticin Glycosides, and occurs in the roots after they have been kept a while (although it does look like it is assembling itself from the above rather than 'breaking down' per se).
Whereas the petals of the blue version of Scarlet Pimpernel (Anagallis arvensis ssp. arvensis) (Blue Pimpernel) (Anagallis arvensis ssp. foemina) contains crystals of the blue-purple anthocyanin Malvidin-3-Rhamnoside those of the red version contain the red anthocyanin Delphinidin, although other possibly more reliable sources say that they contains a mixture of several anthocyanins:
Callistephin (aka Pelargonidin-3-O-βGlucopyranoside),
Oenin (aka Malvidin-3-O-βGlucopyranoside) as well as the blue-purple Malvidin-3-Rhamnoside in various proportions (after all, the petals do tend towards purple in the centre, and are not uniformly pigmented).
Callistephin, chemically Pelargonidin-3-O-β- -Glucopyranoside, is another of the red anthocyanins found in Scarlet Pimpernel (and in the berries of Strawberry, in Purple Corn (aka Purple Maize) and in the skins of those Grapes used to brew the red wines Cabernet Sauvignon and Pinot Noir.
Oenin, chemically Malvidin-3-O-β-GlucoPyranoside, is one of the red-purple anthocyanins found in the flowers (petals) of Scarlet Pimpernel (and in the skin of Grapes) and is thus found imparting colour in red wine. Your Author does not yet know whether Oenin was first found in Oenanthe species (Water Dropworts), or in Oenthera species (Evening-Primroses), or neither.
Malvidin-3-Rhamnoside is a blue anthocyanin and occurs in greater concentrations in Blue Pimpernel (Anagallis arvensis ssp. foemina) which possesses far less (if any) of the other two anthocyanins above. Blue Pimpernel is just a morph (a sub-species) of Scarlet Pimpernel, and just has some differing anthocyanins than Scarlet Pimpernel. Only the petals are blue, every other part exhibits the same colours as the scarlet morph. It seems that the sunnier it is, the more the blue morph form is preferred. It also copes better in dry conditions than the Scarlet morph. Blue Pimpernel occurs in great swathes in the sunny hot Mediterranean around Malaga airport (which is in Spain). The blue morph also flowers three weeks earlier than does the Scarlet morph, which also occurs in the Mediterranean (but less often), an advantage in the Mediterranean where the soils can dry out very quickly. But no one really knows why the blue morph is the preferred morph in hot sunny climates. See Plant Hormones.
Without the glycoside unit, Malvidin itself is said (they may be talking about its glycosides!)) to be responsible for the blue coloration of the petals of some blue Primula species (
Primulas are normally yellow!). As Malvidin it is also one of the (reddish) pigments in the grapes of
Grape Vine (Vitis vinifera) and thus also occurs in red wine. Like many other Anthocyanidins, the colour of solutions of Malvidin is sensitive to the pH of the environment: it is red in acidic or neutral pH environments, and blue in alkaline (basic) environments.