Toothwort
can be found throughout the British isles in woodland,
hedgerows, and coppices, usually on calcareous fertile soils. It
is parasitic on a range of trees and shrubs, especially Alder,
Hazel, Beech and Wych Elm.
Here is a long
interesting quote about Toothwort from a very good Wild Flower
Guide, which contains not only a flora, but also a Natural
History of Wild Flowers: (Alasdair Fitter "Wild Flowers
of Britain and Northern Europe", general editor David
Attenborough, Collins New Generation Guide, 1987).
"The most
remarkable parasitic plant must, however, be toothwort, which is
closely related to the broomrapes. It too parasitises the roots
of other plants, particularly hazel and wych elm: but it does so
by means of pad-like suckers which penetrate through the host's
tissues into its nutrient transport system. Toothwort has
extensive underground stem, liberally coated with fleshy whitish
'leaves; at interval these emerge to form aerial stems, which
bear flowers as well as tooth-like leaves.
These leaves contain no chlorophyll and so are clearly not
concerned with fixing solar energy, particularly since they are
most under the ground. It has been suggested that they are, in
fact, complex traps for soil animals, with a central chamber
lined with digestive glands, much like those of the more
familiar carnivorous plants such as sundews and bladderworts. If
so, toothwort is nutritionally about as different from other
plants as is conceivable, for it is both a parasite and a
predator.
It may be however, that these glands represent the solution to a
different problem. All plants transport substances within
themselves dissolved in water, and when it reaches its
destination, the water is lost by evaporation, typically from
its leaves. Toothwort, however, is an underground plant for most
of its life and so must loose water by some other means. Water
naturally moves from dilute to concentrated solutions; the
solution in soil is much more dilute than in plant tissues, so
that the tendency is for water in soil to move into plant
tissues. The leaves on toothwort's underground stems probably
act to pump water out into the soil, against its natural
tendency to move in the opposite direction."
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