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16th June 2011, Glascarnoch Loch, Wester Ross | Photo: © John Brailsford |
Taller (to 6 inches) and more robust than the similar Oblong-Leaved Sundew |
16th June 2011, Glascarnoch Loch, Wester Ross | Photo: © John Brailsford |
Un-like Oblong-Leaved Sundew which has sticky hairs in an oval shaped area near the tip, Great Sundew has leaves that gradually taper to a hairless similar in outline to a lacrosse stick. |
16th June 2011, Glascarnoch Loch, Wester Ross | Photo: © John Brailsford |
The hairs are red with sticky transparent blobs on the ends and occupy one side of the flattened yellowish-green 'leaf', more reminiscent of a cat brush. The other side is nominally free of hairs. |
16th June 2011, Glascarnoch Loch, Wester Ross | Photo: © John Brailsford |
When an insect lands on the hairy side, it triggers the release of chemicals responsible for closing the 'leaf' up onto the insect, whereupon the plant slowly digests the insect with enzymes, absorbing the released nutrients for its own purposes. The leaf will curl over starting at the top in about a minute from being triggered. |
Easily mistaken for : Oblong-Leaved Sundew
Hybridizes only with : The commoner Round-Leaved Sundew (Drosera rotundifolia) to produce
No relation to : The clear liquid mucilage at the end of each hair is viscous, and traps the insect, which is attracted to the plant by the sugary scent coming from the glands. When small prey land on the hairs, the hairs are triggered into moving towards the insect, physically trapping it to prevent escape from the stick mucilage. This takes place over a few minutes. When the insect is thus trapped, the leaf blade bends over upon itself in order to secrete additional mucilage on the insect to first liquidise it and then absorb the nitrogenous fluids for the plants own use. Only the indigestible chitin exoskeleton of the insect is left over, when the plant un-furls ready to catch the next un-wary insect. Nitrogenous compounds are in short supply in the boggy peaty uplands that the plant grows upon. Digesting insects are not the only way the plant survives, it does actually also have roots with which it feeds itself. The insects are supplementary, but necessary. However, not all insects are trapped by Sundews: ants are able to plunder Sundews with impunity, making off with 2/3rds of the sticky spoils. The plant is normally lime-green, but some parts redden under strong sunlight as a protection from the suns rays. The flowers are white, actinomorphic, with five petals, five sepals and five stamens. The flowers are seemingly shy to appear, your author has not seen any despite traipsing through miles of upland bogs over the decades he has been walking the mountains. But then bogs are not something walkers like to linger on for long for fear of sinking too far. In the World there are more than 194 species of Sundew (only 3 in the uk plus two hybrids). The sticky transparent mucilage consists of polysaccharides mixed with the ions of calcium, magnesium, potassium and sodium producing an acidic mixture with a pH of 5. These sweet polysaccharides attract insects. Sundews also produce enzymes called chitinases which are able to break down the chitin exo-skeleton of insects which the plant then absorbs as part of its diet. Sundews also contain enzymes called proteases which are able to break down proteins. Sundews contain two types of glands: secretory glands which secrete a sweet attractive mucilage, and sessile glands which absorb the soup of digested chitins, proteins and fatty acids once contained in the insects it has trapped.
The sequence of events is thus outlined:
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anglica ![]() |
⇐ Global Aspect ⇒ |
Droseraceae ![]() |
![]() Drosera (Sundews) |
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