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Thursday, 12 June 2008 |
French: Lathrée – Latin: Lathraea clandestina.
When a friend asked ‘Are they crocuses ?’
I saw that he needed some botanical
formation (instruction), as the French would
say. These brilliantly purple flowers, growing
in damp places at the base of poplar or
willow trees, have no connection at all with
crocuses. The form of the flower is more
akin to that of a snapdragon. In much of the
west of France they are common in April and
May. They do not grow in the east, nor in
most départements in the north. In some
districts they are spectacular and cannot be
overlooked. It is odd that there is no common
French name, other than that borrowed from
the botanical Latin.
Very rarely, you may find the flowers in
some notable gardens in England. It has
escaped and is now found there in the wild in
a few locations. The plants are very difficult to
establish in cultivation. That is because of
their unusual biology. The plant is a parasite
on the roots of the trees. It is almost
impossible to transplant it so that it will attach
itself to the roots of the host. The most
sensible method is to germinate the seeds next
to the roots. How can that happen in nature?
The fruits are large capsules, a centimetre
across, which when ripe burst explosively.
Inside are seeds huge for the size of the plant.
Each capsule normally contains four seeds.
Each seed is towards half a centimetre in
diameter. They float, and this is probably the
way the seed is usually distributed. The seed
ends up against some roots of the willow or
poplar and germinates. A young root of the
toothwort penetrates the tissues of the host
and the next generation commences.
The only remnants of the leaves are found
underground on thick stems. They are white
and shaped like teeth … thus the name. But
even these leaves are odd. The question has
been asked among botanists, “How does
water, and with it the nutrients, move in the
toothwort?” That is not so strange a question.
In all green plants, water evaporates
(transpires) from the leaves and in so doing
there is a water column sucked from the soil to
the topmost height. Toothworts have no
transpiring leaves to generate this flow. The
hollow cup formed to the inside of an
underground leaf is always moist and oozing
water. Possibly glands push out the water and
thus generate a flow from the roots of the host
carrying with it the essential nutrients.
There is a far more common relative in the
northern regions of Europe. This is Lathraea
squamaria – the common toothwort. It is
dirty white in colour everywhere, so is more
likely to be overlooked. That species most
usually parasitises the hazel tree.
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