The Bladderworts (Utricularia) are aquatic carnivorous plants which have small bladders in which they trap microscopic animals.
There are 6 British species, but most of them are impossible to identify accurately without microscopic examination unless they are flowering. Only Utricularia minor flowers freely in Scotland.
This picture shows Utricularia stygia growing on the margin of a loch on Skye.
An introduced Utricularia species, possibly U. macrorhiza, grows close to our home, and this photo taken under the microscope shows the bristles on the sides of the leaves, which are also present on Utricularia stygia. In the picture above, you can see that Utricularia minor has no such bristles.
The most reliable way of separating the species is by microscopical examination of what are known as quadrifid hairs, which are inside the back of the bladders. We have used a stain to show these more clearly.
The first picture shows U. stygia, in which the hairs form an X.
For more pictures of bladderworts, see the Bladderwort page on our site.