A blue form also exists.
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.
Whereas the petals of the blue version of Scarlet Pimpernel (Blue Pimpernel) 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 Strawberries, 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)
Malvinidin-3-Rhamnoside is a blue anthocyanin and occurs in greater concentrations in Blue Pimpernel which possesses far less (if any) of the other two anthocyanins above.