Download David Chapman explains how our beachside flora has adapted to

NATURE’S WAY : DUNE FLOWERS
A
lthough beaches are
beautiful, fascinating
places, they provide a harsh
environment for plant
species. However,
numerous varieties thrive on the dunes
and are well worth seeking out on your
next trip to the seaside.
The problems facing any plant
attempting to grow on sand are fairly clear.
Sand contains little in the way of compost
so fresh water tends to drain straight
through and beaches are usually exposed
to strong winds which strip plants of
moisture. It isn’t uncommon for salty
spray to be lashed over beaches and dunes
during storms, exacerbating the problem,
and shifting sands can also cause plants to
become buried.
But plants have adapted remarkably to
these conditions, and finding them brings
its own rewards.
David Chapman explains how our
beachside flora has adapted to
cope with the environment
MARVELLOUS MARRAM
The supreme stabiliser of sand is marram
grass – an ornate species that has the
ability to grow well even when buried.
It has a huge root system which acts like
a net to hold the dunes together. Look
closely at its leaves and you will see a
waxy, smooth outer layer designed to
minimise water loss. These leaves are
also tightly rolled to retain moisture – but
when rain creates a surplus of water they
unfurl slightly to allow sap to course
through the plant’s system.
One of my favourite plants on dunes
and shingle beaches is the sea holly, whose
spiny leaves are designed specifically to
reduce water loss. Their unusual but
rather attractive silvery colour reflects the
sun’s heat and a thick waxy cuticle retains
moisture while protecting the plant from
the effects of salty spray. Sea holly also has
incredibly deep roots, sometimes
extending two metres downwards, which
draw water that is less tainted by salt.
A very different flower that can be
found on shingle, sand dunes and rock
walls is the biting stonecrop. This one
tackles the problem of desiccation
(moisture loss) in another way. Its stem
structure is specifically designed to store
water, collecting it in times of plenty such
as after a rain storm and using it steadily
throughout the hot, dry summer months.
Biting stonecrop is tempting to
butterflies, and many other varieties of the
plant, known to gardeners as ‘sedums’, are
grown in gardens specifically to attract
these colourful insects.
Another plant that can be found
growing on shingle, but only where some
Sea holly and marram grass
growing on the beach near
Gwithian in Cornwall
52
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organic debris has built up, is the wild
carrot. The creamy-white, dome-shaped
flower heads are actually made up of
hundreds of tiny flowers, often including a
single red or purple sterile one in the centre.
The wild carrot is closely related to the
cultivated type and occasionally
hybridises. Although it lacks the bulbous
root of the familiar vegetable, if you crush
its leaves between your fingers you will still
notice a distinctive carrot-like aroma. Its
stems and leaves are covered in coarse
hairs – an evolutionary strategy which
helps the plant cut down on moisture loss
by reducing air movement at its surface.
PRUDENT PLANT
Meanwhile, thrift (or sea pink) grows on
rocks as well as sandy ground above the
high tide line. ‘Thrift’ or ‘thrifty’ are words
related to the verb ‘to thrive’ and have their
origins in the Norse word ‘thrifask’ which
meant ‘frugal’. Thrift is certainly frugal
with water, epitomised by its leaf
structure. Unlike many flowering plants
which feature large, flat leaves, the leaves
of thrift are needle-like, giving them a
smaller surface area through which to lose
water by transpiration.
Thrift plants usually form pillowshaped mounds, built up through
generations of growth. These ‘pillows’
help the plant to retain moisture around its
roots and in spring and summer amazing
shows of colour can be seen.
Other species such as the yellow-horned
poppy, sea kale and sea campion can also
be seen flowering on shingle beaches
during August.
So, if you are basking on a beach this
summer and feeling a bit thirsty, spare a
thought for the plants – they’ve got to wait
for the next shower. Still, it is Britain so
they shouldn’t have to wait too long! ■
From top: wild
carrot; thrift; biting
stonecrop
LOOK OUT FOR: DARK GREEN FRITILLARY
As well as some striking flowers, you should find some butterflies
on the dunes. Although it can be found in a variety of habitats, the
dark green fritillary shows a liking for dunes and can be spotted in
July and August. Typical of all fritillaries, this fine-looking butterfly
has a chequered pattern of orange and brown markings on its back;
underneath it has
large silvery spots
with a greenish wash
to its hind wing,
hence its name. It is a
relatively large
butterfly, with a
wingspan of between
6cm and 7cm, and is
a strong flier so is
often difficult to see
close up.
August 2013 The Caravan Club Magazine
53