Round-leaved Sundew

The Round-leaved Sundew, Drosera rotundifolia, (Drosera meaning ‘dewy’ in latin) is a small carnivorous plant found in bogs, it is locally common but hard to find, in England its strongholds are on our acid uplands, in particular those of the Northwest.

A small plant, with reddish coloured ‘leaves’ covered in sticky hairs the Round-leaved sundew grows in acid bogs which are sparse in nutrients, which is why it has evolved the ability to catch insects . When an insect alights on one of its leaf-like appendages, it becomes stuck, unable to escape, and the plant, sensing this, begins to curl its leaves around the hapless insect to hold it fast.

The sundew then exudes digestive juices and enzymes to get the job done. D. rotundifolia does this by utilising an enzyme called nepenthesin which works best in acid conditions, which is one reason it thrives in acidic soils.

Preferred Habitats

In the Northwest of England there are several places where the sundew grows in abundance, I know of a few sites where it can be found lurking in the mosses, one is at the base of Lamb hill in the Forest of Bowland where it grows in Sphagnum next to a very clear flowing spring, another is on a blanket bog near Silverdale. Both places are open and sunlit through most of the day, as the sundew does photosynthesise even though it ‘cheats’ by eating insects!

It is susceptible to drying out though so is rarely found on south-facing slopes where it would roast in a hot summer and is threatened by encroaching woodland in other places, so it is quite vulnerable to habitat loss, this is something that needs to be considered in any rewilding or woodland regeneration schemes.

Darwin’s Obsession

“I care more about Drosera than the origin of all the species in the world”.

Charles Darwin was famously enamoured with the sundew, his works contain several sketches of the plant and its flowers, he was particularly interested with how it evolved into its particular niche, and botanists have long had an interest in the plant’s medicinal properties, including for heart problems.

One of Charles’ close friends once penned a humorous ditty entitled From the Insects to their friend, Charles Darwin in which, amused by Charles’ obsession with Drosera he included these lines;

I never trusted Drosera,

Since I went there with a friend,

And saw its horrid tentacles

Beginning all to bend.

I flew away, but he was caught,

I saw him squeezed quite flat—

I don’t go any more to Plants

With habits such as that.

Darwin’s perhaps inherited his fascination with carnivorous plants from his grandfather, Erasmus Darwin, indeed here is a stanza on Drosera itself from Erasmus’ 1789 book The Botanic Garden.

Queen of the marsh, imperial Drosera treads
Rush-fringed banks, and moss-embroider’d beds;
Redundant folds of glossy silk surround
Her slender waist, and trail upon the ground;
Five sister-nymphs collect with graceful ease,
Or spread the floating purple to the breeze;
And five fair youths with duteous love comply
With each soft mandate of her moving eye.
As with sweet grace her snowy neck she bows,
A zone of diamonds trembles round her brows,
Bright shines the silver halo, as she turns;
And, as she steps, the living lustre burns.

(Erasmus Darwin 1791)

Hopefully this graceful sundew can continue to flower in her ‘moss-embroider’d beds’ as she is such a wonder to find and her health reflects that of the rest of the moorland and the marshes she reigns over.

A B-H

(July 2024)