Been there, dune that

I’d like to take you to the other patch I’ve chosen in which I’m going to try to list all the species of plants I find. Other patch? Yes, the first was in the previous post.  That was in the hills, this is by the sea, and already the comparison is showing me a lot about each habitat.  Here we are at Marseillan-plage:

The dunes of Marseillan-plage, looking west (promenade up on the left)

The dunes towards the port on the east side – promenade now on the right of the image

The town of Marseillan is a very old port on the Étang de Thau, founded in the 6th century BCE by the Greeks; facing the Mediterranean its neighbour Marseillan-plage is – there are no other words for it – a brash new tourist resort, which has invested a great deal of money in the last year to become, well, even brasher. But it has a botanical jewel in its narrow system of dunes.

Jewel? Doesn’t it look just like a patch of dried-out weeds?  Look closer. There are at least two separate main ecosystems here, separated by the promenade between the town and the harbour: the dunes nearest the sea are the least stable, blown by wind and spray, and only a few species can take the conditions: Euphorbia paralias (sea spurge) which I blogged here, Elytrigia juncea (sand couch grass), and Ammophila arenaria (marram grass) are examples.  The Euphorbia can store water in its stems and fleshy leaves.

Elytrigia juncea – sand couch grass – Chiendent des sables

These are the shifting sands – dunes vives in French – pegged down by rows of fencing made of chestnut stakes. These are in place all along the coast, after the damage of a great storm in November 1982 awakened the authorities to the gradual erosion of the coastline by the prevailing east to west currents.

On the town side of the promenade and sheltered by it from the worst of the wind and salt spray, a much more diverse flora has established itself. Although the sand is infiltrated by seawater, there is a layer of fresh water within the sand which lies on top of the salt because it’s less dense, and a plant with roots deep enough to reach this layer can survive. Even so, the plants here in the arrière-dunes show even stronger adaptations to drought than on the sauveplaine. For example, this clump of Paronychia argentea has a low, dense growth habit, and refective silvery bracts round the flowers, creating its own shade underneath.

Paronychia argentea

Many dune plants are covered in a thick downy coat of hairs, which both reflect heat and reduce evaporation, such as this Sea medick (Medicago marina), which is rarely seen away from the coast.

Sea medick – Medicago marina

Others have leaves reduced to slender leaflets, such as Centaurea aspera (rough starthistle) and Anthemis maritimus.

Centaurea aspera – identified by its 3-spined bracts, and Anthemis in the background

One unexpected discovery was the dry stem of this broomrape. These plants are completely parasitic on other plants, and can often be identified by spotting the host plant nearby.  In this case the yellow composite is a clue to its probable identity as Orobanche minor (common broomrape), and this species is often found near the sea. The grass in the picture is Lagurus ovatus : hare’s tail or bunny-tail grass, or Queue-de-lièvre.

Broomrape – Orobanche minor? – and yellow composite which it may be parasitising

I’ve found a couple of other broomrapes recently: they’re stunning flowers and I’ll write a post about them soon.

At the foot of the landward side of the fixed dunes, just before the houses begin, the terrain is more fixed, the water is closer to the surface and perhaps some organic matter can accumulate to enrich the sand – at any rate, some plants here resemble those of further inland, or even those of gardens. For example, a stout Lavatera arborea (tree mallow) would grace any front yard, and the wild leeks (Allium ampeloprasum) are the same as those on the sauveplaine.

Lavatera arborea – tree mallow – at the foot of the arriere-dunes

Allium ampeloprasum- wild leek – just opening in the dunes

The Marseillan patch study is now up to 24 species – I’ll work on a list which I’ll set up on another page on the blog here, and keep updated. The close study of two very different areas is fascinating, and it’s showing me that the dune season is much more compressed, with some flowering seasons over before those in the hills have really started. The grasses in the two places are completely different – I’m trying to get a grip on identifying these.  And over the summer I expect to see the real dune specialists which flower most of the year, such as Anthemis, and others yet to be discovered. But the greatest wonder of the dunes is that very different habitats are found only metres apart, and so in ten minutes you can have a good lesson in ecology. I’ll be suggesting this as an important asset to the municipality – there’s been a lot of redevelopment in the town in the last year and I’d hate for this area, which is like a wild park in the centre of town, to be disturbed to lay drainage pipes or to build ice-cream stands. The rest of Marseillan-plage is concrete, with imported palm trees.

Here’s some music from a region I imagine to be as dry and sandy as the dunes. It’s from the album Jama Ko, by Bassekou Kouyate and Ngoni Ba, recorded in Bamako in Mali in 2012, and something I like very much indeed.  This track, Poye 2, also features the bluesman Taj Mahal, a longtime fan of Kouyate.

Coming up next: Close relations: how do you tell them apart?

 

The Blues: Medicago sativa – lucerne (alfalfa)

Time to play ‘guess the odd one out’ of the above photos, taken along the same 10 metres of roadside verge……(clue: you can move the cursor over the images). The answer? They’re all from the family Leguminosae with the characteristic upright standard petal at the back, and a ‘keel’ projecting forward, like garden peas and beans.  But the odd one out is the first one, Psoralea bituminosa, a plant which looks like clover or lucerne but isn’t. The other two are the same species, Medicago sativa or lucerne (often called alfalfa in the UK), though the yellow flower is a subspecies (falcata).  I had to do some close looking and reading to be sure  – more disambiguation!  I’ll explain.

Psoralea bituminosa has a leaf divided into three, like the others, but the leaflets are elongated, and the flower stalks much longer than for the Medicago. It is supposed to smell of tar, due to glands on the leaf which appear as bright points against the light – I couldn’t see these or smell the tar, hence my hesitation in identifying it.  Maybe we have a different variety here, maybe the smell develops later.

The lucerne was easier to identify in the end, because we’ve seen whole fields of it lately, and the plants I saw were escapees from an earlier planting, now naturalised. The flowers are very variable in colour, from deep purple through to light blue, and often have the yellow plants mixed in since the seeds sown for lucerne crops are themselves mixed, and the two varieties interbreed.  In fact the yellow is probably nearer to the parent stock, first cultivated in the near East (Iran and Turkey) over 2000 years ago, but  grown in Europe since the 4th century CE.

A plant with three names: Medicago and sometimes Medick in English because early Roman writers attributed the plant to the nation of the Medes, in present-day Iran.   Alfalfa because the Spanish took the plant and its name alfalfez (from the Arabic al -fisfisa) to South America, and North American settlers took the seeds and name from there, especially from Chile. And  to me the most interesting name of all is lucerne:  not, as I thought, related to a Swiss town, but coming from the Provencal or Occitan word la lusèrna, meaning meaning a little light, or glow-worm.  In fact I think the latter is more likely because the seeds are not only shiny but coiled like a worm.

Lucerne is an amazing plant. Its roots can be up to 15 metres long, and go up to 2 metres deep, giving it great drought-resistance.  It flowers in July when other flowers are fading and so is very important for bees.  It fixes atmospheric nitrogen like many legumes, so does well on poor soils.  It can be cut up to 12 times a year and regrows from its extensive roots – that’s why it does so well on roadside verges which are cut back.  It is the most widely grown forage crop in the world.  It produces an autotoxin – a chemical which inhibits the germination of rival plants.  I could go on, but you have Google and wikipedia just like I do, and it’s time for music.

This is Dinah Washington’s version of the Bessie Smith classic, Back Water Blues. A more rootsy blues for a rootsy blue flower.