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Arum maculatum

Arum Family [Araceae]  

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2th May 2006, Mottistone Common, IoW. Photo: (CC by 2.0) Geoff Toone

2th May 2006, Mottistone Common, IoW. Photo: (CC by 2.0) Geoff Toone
13th May 2008, Panmaen Mawr, Llanfairfechan, North Wales Path. Photo: © RWD
The brown spadix appendix standing shrouded by the hooded spathe. On Lords-and-Ladies the spadix appendage can be either purple-brown or yellow in colour and which can usually reach up to about 1/2 up the opening in the spadix (but on Italian Lords-and-Ladies the spadix appendage is only yellow and usually only reaches about 1/3) of the way up the open part of the spathe.

13th May 2008, Panmaen Mawr, Llanfairfechan, North Wales Path. Photo: © RWD

24th April 2012, Near Gait Barrows, Lancs. Photo: © RWD
The spadix tapers into the bowels of the deep.

24th April 2012, Near Gait Barrows, Lancs. Photo: © RWD
All that can be seen looking deep into the lower half of the spathe is a spidery ring.

24th April 2012, Near Gait Barrows, Lancs. Photo: © RWD
  With the spathe cut off the innards of the lower bulge in the spathe can be seen. From top to bottom: the red spidery ring of 'hairs' on the lower and thinner part of the spadix are sterile flowers, possibly keeping large flies out. The small red spherules are the male flowers. The female flowers are the larger cream-coloured globules. It can be seen that the spathe wraps around with about 30° of overlap, keeping the flies entrapped.

24th April 2012, Near Gait Barrows, Lancs. Photo: © RWD
  The cream-coloured female flowers are destined to become the berries (shown only when both the spathe and spadix have dropped off). It is covered in tiny flies which pollinate the female flowers. The female flowers also have spidery red threads similar to the first ring coming from some of them.

21 Aug 2004, Cumbria Coastal Path, Ulverston. Photo: © RWD

10th Aug 2006, Leeds & Liverpool Canal, Saltaire. Photo: © RWD
The red berries are initially nurtured concealed within the lower bulbous part of the spathe.

28th June 2005, Deganwy, North Wales. Photo: © RWD
The poisonous berries turn from yellow, through orange and finally to red

9th Sept 2008, Hawes Water, Gait Barrows, Lancs. Photo: © RWD
Before dropping off.

12th May 2009, Monks dale, Derbyshire Photo: © RWD
The opposite side of the pulpit. Jack is inside giving his sermon to the congregation.

9th April 2008, Lancaster to Morecambe ex-railway track. Photo: © RWD
The arrow-head shaped leaves appear well before the inflorescence.

4th April 2008, Eskdale Valley, Cumbria. Photo: © RWD
The large bluntly-pointed leaves are wrinkly with prominent veins.

25th March 2015, Chorley, Leeds & Liverpool Canal, Lancs. Photo: © RWD
Quite often the leaves are covered in a random pattern of black splodges which are indented, but these black spots are without the indentations which perhaps come later. The black spots are thought to be due to an anthocyanin (although your Author has never before come across a black anthocyanin). The presence of the spots are said to be governed by a genetic Mendelian factor, the dominant form of which is 'no spots'. In your Authors opinion, only about 5% of plants seem to possess this feature which had so impressed the botanist who named the plant after them.

(Melanustilospora ari)
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11th April 2016, extinct railway track, Waterloo, Conder Green. Photo: © RWD
The above photo is of normal black spots (due to an anthocyanin - one under the influence of a genetic factor - hence only a fraction of plants have these kinds of black spots. Presumably this genetic factor does not switch on the blackness all over the leaf, just in select spots on the leaves - which occurs on perhaps only 5% of plants of Lords-and-Ladies. [Your Author does not have a photo of the black spots on the leaves due to the Basidoycotal ari infection]

And this is the source of the confusion over whether the infection is real or not. There are several reports of it being real, and several refutations (possibly based on examining leaves covered in black splurges which were not caused by a basidomycotal infection but instead by an anthocyanin). The two apparently differ.

Some Lords-and-Ladies with black spots are indeed caused by a Basidomycotal smut fungal infection by the fungus Melanustilospora ari (aka Melanotaenium ari). This fungus is named after its own colour: melano = black. It causes black spots on the upper surface and pustules directly underneath them which release spores of some kind. But most of those Lords-and-Ladies with black spots appear not to be caused by an infection, but by genetics and an anthocyanin. Those with black spots caused by this fungus will often die, but those due to an anthocyanin will not.

There is another infection which can cause marks on the leaves of Lords-and-Ladies: the rust fungus Puccinia sessilis which can infect the leaves of Arum plants. But rust fungi impart a yellow/orange colour to plants (not black) hence their name.

If any reader has photos of Arum leaves infected by either the orange-coloured rust fungus Puccinia sessilis or by the black blemishing Melanustilospora ari then your Author would gladly display them here with acknowledgements.

Easily confused with : Rare Lords-and-Ladies but only if you happen to be in the deep south of England (or in a garden) where that is found.

Using another of its common aliases, Cuckoo Pint has no relation to : Cuckooflower (aka Lady's Smock) (Cardamine pratensis) [a plant with similar name]

And using yet another of its aliases, Jack-in-the-Pulpit, it has no relation to Jack-by-the-Hedge (aka Garlic Mustard) (Alliaria petiolata)

Arum plants contain the toxic glycosidic saponin aroin(e), aroidin and aronin, Coniine-like alkaloids, which depress the Central Nervous System. Other toxins include Cyanogenic Glycosides, and calcium oxalate raphides (raphides are sharp needle shaped crystals).

Starch extracted from the root was formerly used for starching laundry, but it contains the same acute irritant as does the acrid juice contained in all parts of the plant, so its use in this context was abandoned. Portland arrowroot (not the same as 'arrowroot' which is obtained from a plant called 'Arrowroot', a native of far away climes which is used in the making of arrowroot biscuits) and Portland sago were food preparations obtained from baking the powdered root, the toxic components presumably being destroyed by the baking process.

The attractive red berries are the most poisonous parts of this plant, but fatalities are rare due to the burning sensation in the mouth when the berries are eaten. This is followed by swelling of the tongue, salivation, strong convulsions, nausea, bloody vomiting and severe gastroenteritis. Higher amounts lead to arrhythmia and paralysis of the central nervous system.

Contact with the sap can cause severe dermatitis.

The spadix generates its own heat (rather unique in a plant) to vaporise amine molecules (which have a foetid odour) in order to attract certain flies known as 'Owl Midges' in the hood (spathe), which in trying to escape, pollinate the stigmas. The flies are imprisoned until the male flowers mature, when the spathe drops off revealing the berries. This detectable heat-generation process could be seen as un-likely, given the low metabolism of plants, but seems to be true of Lords-and-Ladies.

The 'i' in 'pint' in Cuckoo Pint is pronounced similar to the 'i' in mint, and not, as most assume, as in 'a pint of beer'. This pronunciation comes about because 'Cuckoo Pint' is derived from the old English cuccopintle meaning 'Cuckoo's Penis', which it apparently resembles. In a similar vein, some folk call it 'Naked Boys' or 'Willy Lily' although it does not belong to the Lily Family.

A Protogynous flower is the opposite of a Protandrous flower. In a Protogynous flower the stigma is receptive to pollen before the anthers open and release their pollen, during the interval the stigma becomes unresponsive to pollen. Thus self-fertilisation is again thwarted. Examples of flowers exhibiting protogyny include the flowers of Figwort, Plantain, Magnolia, Hortonia and Daphnandra.

Lords and Ladies (Arum maculatum) is also protogynous but with a slightly different strategy. At first both male and female flowers deep within it are sterile. But then one day the female sexual organs deep within the spadix become active and they release an odour attracting the tiny Diptera flies which then become trapped by the expanding but still sterile male flowers in a ring above the female flowers at the bottom. On the second day the male flowers become active and allow the trapped flies to escape, and as they do so they unintentionally take sticky pollen grains with them. When they visit another Lords-and-Ladies flower they fertilise it with the pollen.


Oxalic Acid is the smallest di-carboxylic acid and about 3000 times stronger than Acetic Acid. Highly insoluble in water, it is present as crystals in many plants, including Cuckoo Pint, which contains about 0.3% in the berries, but is present in other parts.

Oxalic Acid is usually present as extremely fine long and narrow crystals known as raphides, which are more dangerous because of their ability to pierce cells. Oxalic Acid is toxic. Crystals of one of the highly insoluble salts of Oxalic Acid called Calcium Oxalate are apt to accumulate in the kidneys as kidney stones.

Both Lords-and-Ladies and Italian Lords-and-Ladies contain a volatile components in the spadix, EthylAmine, IsoButylAmine and IsoAmylAmine, which together have an odour reminiscent of mice urine.

The literature on the poisonous constituents of Cuckoo Pint is very sparse, and mainly dates back 50 years or more. Bearing this in mind, your Author has managed to track down several supposed constituents:


Triglochinin, a Cyanogenic Glycosides derived from oxidative cleavage of the ring in Tyrosine, is present at up 100ppm in all parts of the plant. As such, it is one of the toxic components present in all parts but especially the berries. It is quick-acting and can cause a severe swelling action which may result in death.

Tyrosine itself is one of the natural 21 or 22 amino acids and plays an important role in photosynthesis in plants, acting as an electron-donor in the reduction of oxidized chlorophyll. In accomplishing this feat, Tyrosine itself loses the hydrogen atom in the hydroxyl group attached to the phenyl group (far left). Tyrosine is also the precursor to the black skin pigment melanin.

There are many reports of Cuckoo Pint also containing un-named and un-identified Cyanogenic Glycosides (which release prussic acid, HCN, when the leaves are damaged). One report suggests that that this Cyanogenic Glycoside is Dhurrin (which is similar to Prunasin [but that lacks an extra -OH moiety] and which is found in several other plants, including Bracken). Scientific papers also report un-named Saponins as being present. Note also the similarity to Triglocinin, another cyanogenic glycoside with a similar modus operandi.


A trace amount of Nicotine is also present in the leaves, at a concentration of 0.7mg/kg, which is unlikely to cause problems. This is unusual, previously Nicotine was only known in plants belonging to the Nightshade Family (Solanaceae), and especially in the Genus Nicotinia (Tobacco). Nicotine is a very addictive alkaloid, probably as dependence-forming as some of the narcotics such as heroin and cocaine. In low doses of up to 1mg it acts as a stimulant in mammals. It is enantiomeric, existing in two stereo-isometric forms, one dextro-rotatory, the other laevo-rotatory. Only The laevo-rotatory form is produced naturally. The dextro-rotatory form is only half as pharmacologically active as the laevo-rotatory form.


Reportedly smelling similar to the odour of mice urine these three amines were also found, in both this and Italian Lords-and-Ladies.


In many books and research papers mention is made of the plant containing a Coniine type alkaloid, but no one names it, apart from one source. It turns out that it contains 3-PropylPiperidine, which is an isomer of the extremely poisonous alkaloid Coniine, being 2-MethylPiperidine, shown alongside for comparison only, which is contained within Hemlock (Conium maculatum) (and which somewhat coincidentally shares the same specific epithet part of the scientific name, maculatum, which just means 'spotted').

  Arum maculatum  ⇐ Global Aspect ⇒ Araceae  

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Arum maculatum

Arum Family [Araceae]  

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