Jeremy Bartlett's LET IT GROW blog

Cuckoo Pint, Arum maculatum

Cuckoo-pint, Lords-and-ladies, Jack in the pulpit, Parson in the pulpit, Devils and angels, Red-hot-poker, Willy lily, Snake’s meat, Cows and bulls, Adder’s root, Arum, Wild arum, Adam and Eve, Wake Robin, Bobbins, Naked girls, Naked boys, Starch-root, Starchwort, Snakeshead, Cheese and toast, Sonsie-give-us-your-hand, Friar’s cowl, Tender ear. These are just some of the many English names for Arum maculatum, one of our most familiar spring flowers [1].

Like the Dragon Arum and the Mouse Plant, which I have already written about, Arum maculatum is a member of the Araceae, the Arum family. Unlike these, it is a British native, along with its close relative, Scarce Lords-and-ladies, a subspecies of the Italian Arum, Arum italicum subsp. neglectum (see distribution map).

Members of the Araceae have flowers borne on an inflorescence known as a spadix, often partially enclosed in a sheath (a leaf-like bract known as a spathe). When in flower, Arum maculatum is instantly recognisable as a member of the family, and the suggestive shape of its spadix has led to many of the English names. Willy lily is one of the most expressive. But even Cuckoo Pint is rather rude, because “pint” doesn’t refer to an imperial measure of volume, but should be pronounced to rhyme with “mint”, for it is an abbreviation of “pintle”, meaning penis [2].

Section through a Cuckoo Pint (Arum maculatum) inflorescence. The spadix is at the top. The flowers are further down, enclosed in the bottom of the spathe. In order, there is a whorl of sterile hairs, then the male flowers, then a second whorl of sterile hairs and finally the female flowers at the base.

Arum maculatum flowers are pollinated by small flies, mostly female Owl Midges, Psychoda phalaenoides [3]. These are also known as Moth Flies because they are covered in tiny waterproof hairs (setae), which look rather like the scales on moth wings. Their other name is Drain Flies because of where they often live – the larvae are detritivores, feeding on decaying plant and animal matter [4]. 

The inflorescence of Arum maculatum acts as a trap for these flies and they are attracted by the scent of the flowers. This is variously described as smelling “slightly of decay” to “foul and urinous“. Add some warmth and the Owl Midges will come flocking in. The temperature of a mature Arum maculatum spadix can range from 25 to 35°Celsius and is often up to 15°C warmer than its surroundings. Starch is metabolised to do this; it is stored in the plant’s root tuber. The heat is mostly generated via a separate mitochondrial respiratory pathway by a cyanide-resistant alternative oxidase (AOX), described by Wagner, Krab, Wagner and Moore in a 2008 paper [5]. 

Flies entering the spathe slip downwards to the ripe female flowers at the base of the inflorescence and are trapped by the whorl of hairs between the female and male flowers. If the flies are covered in pollen from another Arum maculatum flower they may deposit it on a stigma of a female flower.

The next day, the sterile hairs wither and allow the flies to crawl upwards along the spathe and escape. (The spadix is too slippery to climb.) By this time the male flowers are producing pollen and the flies will be dusted in this as they leave. If they then visit another Arum maculatum inflorescence they can repeat the process and transfer the pollen to more female flowers. The maturing of male and female flowers at different times is known as dichogamy, and is a way of ensuring that cross-pollination takes place.

In a 2006 paper, Diaz, Amoin and Gibernau investigated further and found that viable seeds were not produced when they transferred pollen from male flowers to the female flowers of the same inflorescence. However, when pollen was transferred between different flowers from the same plant, fertilisation took place (known as geitonogamy) and viable seed was produced. Diaz, Amoin and Gibernau suggested that this could be an advantage where Cuckoo Pint is establishing itself in new locations. [6]

When the female flower has been fertilised, the spathe collapses and the female flowers develop into berries. By August these are bright orange-red. The Wildflower Finder website has some excellent pictures of ripening and ripe berries.

Amongst the plant’s English names are Starch-root and Starchwort. The starch in the root was sometimes used as a foodstuff or for starching clothes. The Elizabethans used Cuckoo Pint starch to stiffen their ruffs and it was also used to starch church altar cloths. Cuckoo pint starch from the Isle of Portland was formerly sold as Portland Sago or Portland Arrowroot (as a foodstuff) and, as Poudre de Cypre (Cyprus Powder) the starch was used as a cosmetic to whiten the skin.

However, Gerard noted that:
“The most pure and white starch is made of the rootes of the Cuckoo-pint, but most hurtful for the hands of the laundresse that have the handling of it, for it chappeth, blistereth, and maketh the hands rough and rugged and withall smarting. [7]”

The smarting comes from the plant’s calcium oxalate crystals (raphides). All parts of the plant are poisonous but the starch in the roots can be extracted by drying and heating.

Eating the plant can can irritate the skin, mouth, tongue and throat. This can result in throat swelling, breathing difficulties, burning pain, and stomach upset. However, the plant has a very acrid taste and you would have to be a masochist to eat the leaves or berries in any quantity. A Modern Herbal relates that “one drop of [the] juice will cause a burning sensation in the mouth and throat for hours”. If you pull up Arum maculatum in your garden, wear gloves to protect your hands.

The Poison Garden website records 23 hospital admissions due to Arum poisoning in the UK during the four years from 1996 to 1999, but none of the incidents caused serious harm.

John Parkinson (on page 378 of his 1629 book “Theatrum Botanicum“) suggests mixing small pieces of Arum root with lettuce and endive, or sprinkling powdered dried root over meat and serving them to an “unbidden unwelcome guest to a man’s table”. “It will so burne and pricke his mouthe that he shall not be able either to eate a bit more or scarce to speak for paine”. Needless to say, I don’t recommend this!

The berries may be enticing to young children, but Cuckoo Pint is a very distinctive plant and it is usually easy for foragers to avoid, although the Easy Wildflowers website has a photograph of Cuckoo Pint and Wild Garlic leaves growing next to each other. The leaf venation is different in the two plants, but a novice forager might “end up with a very unpleasant sandwich“.

Cuckoo Pint is dormant during summer and autumn but new leaves appear from January or early February onwards and the plant flowers from April onwards. The plant is common except in the north-west of Scotland (see map) and it can be found in woodlands and by hedgerows in shady places with moist, well-drained and reasonably fertile soils. It is native to the British Isles, but may be introduced north of Cumbria and southern Northumberland. Although it can be destroyed when hedgerows are removed, it can colonise new areas quite quickly [8]. Outside the British Isles, Arum maculatum is widespread across most of Europe, as well as Turkey and the Caucasus.

The name “maculatum” means spotted and this refers to the purple spots on the leaves. However, these occur in only a proportion of plants (in my experience, less than 50%). It is the unspotted leaves that might confuse a novice forager.

Arum maculatum: spotted leaves

Arum maculatum: unspotted leaves.

Sometimes Arum maculatum leaves have pitted black spots. This spotting (with pustules on the underside of the leaf) is caused by the smut fungus Melanustilospora ari. The rust fungus Puccinia sessilis also infects Arum leaves, as well as Wild Garlic and several other species. (There are some good photos on the fungi.org.uk website.) 

I grow Arum maculatum in our garden, along with its larger relative Arum italicum subsp. marmoratum. They do well on the fringes of our garden in sandy loam, in sunshine or semi-shade, and they are gradually increasing. Each plant is getting bigger as it ages and young plants grow from seed each year. My plants came in a pot from Natural Surroundings but you can buy Arum maculatum seeds from Emorsgate Seeds. The seeds should be sown in the autumn and are slow to start – it may be seven years before a plant flowers.

I find that Arum plants aren’t a nuisance in my garden and if I wanted to, I could dig up and move seedlings before the tubers became too big. If they are taking over your garden, then the RHS website suggests digging up the plants or mulching to suppress them. (I would avoid using herbicides.) Don’t be put off by the fact that the plant is poisonous, as it is a fascinating thing to grow.

Notes:

1. The names I’ve listed for Arum maculatum come from Richard Mabey’s Flora Britannica, Wikipedia and The Poison Garden website. The latter reckons there may be as many as a hundred English names for the plant.
2. This is discussed further in “A Dictionary of Sexual Language and Imagery in Shakespearean and Stuart Literature” By Gordon Williams, A&C Black 2001.
3. If you want to learn more about Cuckoo Pint flowers, the 1991 paper “The pollination of Arum maculatum L. – a historical review and new observations” by Lack and Diaz is well worth a read. Watsonia Volume 18, pages 337 – 342.
4. “The Secret Life of Flies” by Eric McAlister (Natural History Museum, 2017) is a very readable introduction to the weird and wonderful world of flies, including Owl Midges (pages 67 – 68).
5. “Regulation of thermogenesis in flowering Araceae: The role of the alternative oxidase“. A.M. Wagner, K. Krab, M. J. Wagner and A. L. Moore (2008). Biochimica et Biophysica Acta (BBA) – Bioenergetics Volume 1777, pages 993 – 1000.
6. “The effectiveness of some mechanisms of reproductive isolation in Arum maculatum and A. italicum (Araceae)“. A. Diaz, M. A. Amoin, M. Gibernau (2006). Botanical Journal of the Linnean Society Volume 150, pages 323 – 328.
7. Quoted in “A Modern Herbal – Cuckoo-Pint“, which lists many (former) uses for the plant.
8. From “The Online Atlas of the British Flora“.