Wild arum

This is wild arum (Arum maculatum) growing in the copse at the top of Brunt’s Field.

The pale green hood is called a spathe and the purple, poker-shaped inflorescence is a spadix. There are male and female flowers right at the base of the spadix, hidden inside the spathe where it wraps around into a funnel. The female flowers are right at the bottom, these are what will become the familiar red berries; then there is a ring of male flowers, and finally, above the male flowers, a ring of stiff hairs. The hairs are an insect trap.

1. wild arum 2. unopened spathe 3. spadix 4. illustration showing flowers

The spadix smells of faeces and attracts insects, particularly flies. The smooth and slippery spathe decants them into the funnel and down towards the flowers; they push through the downward pointing hairs in search of the source of the faecal smell and are trapped.

Inside the trap it can be 15°C warmer than outside and the trapped insect’s metabolic rate increases so that it is very active, climbing and buzzing around among the flowers looking for a way out. The male flowers dust it with pollen as it pushes through them to escape and it carries the pollen away to another wild arum where, trapped again, it pollinates the female flowers: ingenious!

Wild arum has a multitude of common names: cuckoo pint, Jack-in-the-pulpit, bloody man’s finger, snakeshead, and adder’s root are just a few of them. Because of its suggestive shapes, some of the names are really quite bawdy: priest’s pintle (pintle is an Old English word for penis), Adam and Eve, cows and bulls and Lords-and-Ladies. Even cuckoo pint is suspect: pint is believed to be a shortening of pintle.

Look for wild arum under hedges and on woodland floors, before the tree canopy thickens.


4 thoughts on “Wild arum

    1. It’s clever, isn’t it? I like the bit about the temperature differential boosting the trapped insect’s metabolism so that it doesn’t just sit down next to the flowers and go to sleep.

    1. Yes, they are poisonous. Wikipedia says that the root is edible if properly prepared; however it doesn’t divulge HOW to prepare it properly, just that, improperly prepared, it is highly toxic. The moral is that Arum maculatum and Wikipedia are both to be treated with some care.

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