Hybridises with: Great Butterwort (aka Large-flowered Butterwort) to produce Pinguicula × scullyi (Pinguicula grandiflora × vulgaris), but this hybrid is found in only one small part of southern Ireland.
Distinguishing Feature : the five finger-shaped leaves at the base of the plant which are cup-shaped, able to hold water, and are slimy to catch insects upon which all butterworts feed. Common butterwort has deep violet flowers.
Likes moist or wet ground, bogs and acidic uplands.
This is a Carnivorous plant,
It obtains some supplementary sustenance from insects which are entrapped by the sticky mucilage exuded by the slippery glands in the cup-shaped leaves, where it 'digests' them using several enzymes which are exuded from other glands. I conjecture that the glands must effuse some kind of insecticide, otherwise any creature might easily escape, especially the larger and more powerful ones. We know that certain flowers (chrysanthemums) produce pyrethrin, a powerful (but relatively safe to most mammals except cats) insecticide, so there is previous occurrence of plants producing insecticides. [The author surmises future research may reveal a previously unknown insecticide, which may prove useful agriculturally].
No relation to : Butterbur (Petasites hybridus) or White Butterbur (Petasites albus) [plants with similar names in a differing family (Asteraceae)].
Investigations have revealed that the leaves, although they contain no alkaloids, contain the following compounds:
p-Coumaric Acid, Caffeic Acid,
Ferulic Acid, Sinapic Acid,
Cinnamaldehyde, Catalpol, the flavonoids Apigenin,
Isocutellarin, Scutellarin and Luteolin.
Some histamines at a concentration of 2-13µg/g were also found in the leaf tissue, and this may account for the reported numbing of lips which encounter the surface of Butterworts.
There are two types of glands on the leaves. Those on raised stalks are secretory cells and exude a sticky mucilage which encases the insect in its struggles. Thus incapacitated the insect releases nitrogenous compounds which initiate the release of several enzymes by glandular pores in the leaf surface. The enzymes,
Amylase, digest the insect into a soup that is absorbed by the same pores in the leaf surface, leaving just the exo-skeleton of the insect on the surface. The enzymes are also re-absorbed by the pores on the leaf surface. Job well done, ready for the next insect to perchance upon the leaf surface.
Although nothing to do specifically with Butterworts, the pyrethins are powerfully neurotoxic towards insects acting as insecticides or in lower doses, insect repellents. They are biodegradable, and moderately safe to animals. Both pyrethrin I and pyrethrin II are chemically based around a strained cyclopropane ring (the triangle) and are produced naturally by the commercially grown plant chrysanthemum cinerariaefolium, from which the insecticide is obtained. It is not used directly, but chemically processed to produce the commercial insecticides permethrin and cypermethrin, which unlike their natural precursors the pyrethrins, contain substituted chlorine atoms which presumably increases potency. The strained three-membered ring, cyclo-propane, is likely to be unstable, and to cleave. This is probably responsible for its potency as an insecticide. However, like the anti-fouling paint containing tributyl tin, pyrethrins are extremely toxic to marine life as well as to insects (for which they are targeted), bees and animals such as pets. They are neurotoxins. Symptoms of intoxication by animals include lethargy, muscle twitching, convulsions, seizures and death. The symptoms for mammals and humans are similar but less severe, and include itching due to their allergenic properties. The main saving grace of these pyrethrins, unlike tributyl tin) are that they decompose easily in the environment, and are non-accumulative.