ROUND-LEAVED SUNDEW

Drosera rotundifolia

Sundew Family [Droseraceae]

month8jun month8june month8jul month8july month8aug

status
statusZnative
flower
flower8white
inner
inner8yellow
morph
morph8actino
petals
petalsZ5
stem
stem8round

6th July 2007, Little Langdale, Cumbria. Photo: © RWD
The most common Sundew. Probably more than one plant intertwined here.


5th Aug 2011, Lingmell Fell, Cumbria. Photo: © RWD
Two flowering stems thrust skywards from near the centre.


5th Aug 2011, Lingmell Fell, Cumbria. Photo: © RWD
Two flowering stems arise 6 inches from near the middle of the basal rosette.


28th Sept 2008, Seathwaite Tarn, Cumbria. Photo: © RWD
A basal rosette of round leaves rather than oblong as in Oblong-Leaved Sundew. Flowering stalks appear from the near the centre of the rosette (buds arising in photo)


1st June 2010, Duddon Mosses, Broughton in Furness. Photo: © RWD
Un-like either Oblong-Leaved Sundew or Great Sundew the leaves abut abruptly onto the stalks and do not taper into them.


1st June 2010, Duddon Mosses, Broughton in Furness. Photo: © RWD
The clear sticky mucilage on the tips of the hairs have ensnared an insect, the mucilage having rubbed off the hairs it has touched.


6th July 2007, Little Langdale, Cumbria. Photo: © RWD
Just the upper surface and edge of the leaf are covered in sticky hairs, forming a pin-cushion. The leaves are lime green, but redden in strong sun.


6th July 2007, Little Langdale, Cumbria. Photo: © RWD
A flowering stalk slowly un-curls from the centre, the top-most section still to un-furl. Flower buds have not yet opened.


6th July 2007, Little Langdale, Cumbria. Photo: © RWD
A curled-up flowering stalk spirals around (with un-opened flower buds). Another next to it is bent into a U-shape, yet to fully erect.


5th Aug 2011, Lingmell Fell, Cumbria. Photo: © RWD
This flowering stem has more flowers than do most, although not open in the rain.


28th June 2018, Brownsea Island, Dorset. Photo: © Jill Stevens
When flowering the flower stalk erects itself bolt upright straightening out the umbrella-handle curve in the upper stem.


28th June 2018, Brownsea Island, Dorset. Photo: © Jill Stevens
At last, a specimen with an opened flower :-)
5 white petals with 5 splayed-out but short filaments with anthers. The flower buds just below the top have yet to open, whilst those below them look like they might be turning to fruit.


Easily mis-identified as : Oblong-Leaved Sundew (Drosera intermedia) but that has oblong rather than round leaves.

Hybridizes with :

  • The less common Great Sundew (Drosera anglica) to produce Obovate Sundew, but unlike Great Sundew, it grows over a much larger area, occupying mainly the most of the mountains of Scotland.
  • Oblong-Leaved Sundew (Drosera intermedia) to produce Belezeana Sundew (Drosera × belezeana.

Uniquely identifiable characteristics

Distinguishing Feature : The round leaves should distinguish it from two other sundews, although it does hybridize with them.

No relation to : Purple Sundew (Disphyma crassifolium) a serpentine rock speciality in the Dewplant Family [Aizoaceae].

Grows in upland acid peat bogs and other wet upland places. It is carnivorous eating insects. See Great Sundew for how it accomplishes this.

Round-leaved Sundew has been used in folk medicines for a long time to treat colds, coughs, bronchitis and asthma. In Italy it is used in a liqueur.

Sundews are carnivorous plants which trap insects in their leaves, dissolve them and absorb the resulting nutrient soup for use by the plant itself. The leaves exhibit Thigmonasty, moving in response to touch. See Great Sundew for modus operandi.

NAPHTHOQUINONES and NAPHTHAZARINS

The compounds shown below are to be found in many plants of the Drosera Genus (Sundews).


Plumbagin is the major naphthoquinone contained within the Drosera Genera, (Sundews) of which Round Sundew is one. Plumbagin is a toxic bright yellow dye which is also found in the blackish drupe (commonly also called a walnut) of the Walnut tree. Round-leaved Sundew has in the past been used for dying cloth a bright yellow colour in Scotland, when it is known as 'lus-na-fearnaich'.

7-methyl Juglone has the methyl group placed on the opposite ring from that of Plumbagin. Compare with Juglone.


Biramentaceone is the dimer of 7-methyljuglone, repeated again here for direct comparison.


Other naphthoquinones contained within Drosera species are Droserone, HydroxyDroserone. HydroxyDroserone is the only Naphthazarin shown here. Naphthazarines are NaphthoQuinones with two para-positioned OH groups. The glycosides of both Drosereone and 7-Methyljuglone are also present in Sundews.


The Venus Flytrap (Dionaea muscipula), a member of the same Drosearaceae Family that Sundews are in, contains both Diomuscione and Muscipulone, but these compounds are not found in Sundews themselves. Their names (with 'musk' spelled as 'musc') imply that they have an aroma - one which attracts flies.


  Drosera rotundifolia  ⇐ Global Aspect ⇒ Droseraceae  

Distribution
 family8Sundew family8Droseraceae

 BSBI maps
genus8Drosera
Drosera
(Sundews)

ROUND-LEAVED SUNDEW

Drosera rotundifolia

Sundew Family [Droseraceae]

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