Polypodies

A magnificent fern grows on an old Ash-tree on the banks of the Dordogne. It is a Polypody, but which one? There are three species in Perigord and sometimes a hybrid between two of them is found. The species are very much alike. To be sure of your identification you have to look at the sores (the lids of the sporangia) under a microscope et count the cells. Well, in the field you normally don't carry a microscope.

Hybrids are often polyploids - the number of chromosomes has doubled or tripled - and thus the organs (leaves, flowers) can be much larger than those of the parents. This one is really big, it has fronds up to 70 cm. So probably it is the Hybrid Polypody (Polypodium x mantoniae).

It has other characteristics of its presumed parents. The big pinnate leaves are long triangles with toothed margins as in the Intermediate Polypody (Polypodium interjectum). The leaves are planar, the pinnae - the segments of the leaves - are a bit hanging in the picture but they are basically all in two dimensions as in the Common Polypody (Polypodium vulgare).


In this fallen tree lives one of the two parents, Common Polypody, as in an apartment building with several floors.

They are rather small and the fronds are long with parallel margins.

Often Polypodies grow on trees, but you can find them also on the forest floor. Or maybe this one lives on a dead trunk hidden under fallen leaves? Possibly this is an Intermediate Polypody (Polypodium interjectum) considering the shape of the leaves, slightly triangular with the basal pinnae uplifted. But this is just a guess!

Burr Cucumber

Burr Cucumber (Sicyos angulata) is an invasive plant that loves summer sun and humidity, two things abundantly available on the Dordogne river banks. This plant from North America can be found in the West of Aquitaine since about fifty years and, following the rivers, it makes progress in the East. Slowly, in 2010 it had not yet arrived in Bergerac. But now there are also Burr Cucumbers in Coux et Bigaroque and maybe also further away.

It is a kind of monster, its creepers can reach more than 8 meters away. It covers the river banks and their vegetation, and it climbs...

... and climbs. In fact, it thrives like a cucumber or a pumpkin on the compost heap. As it should be for a member of the Cucurbitaceae family.

Until now there has not been a little morning frost this year, so Burr Cucumber goes on flowering.

It is not easy to find beauty in it, it is a messy plant, with its unkempt creepers and disheveled leaves that grow in any direction. But this is also a question of taste, is n't it?

The star-like fruits are festive, anyhow, like too-early christmas tree baubles.

In spite of its name the fruits do not look at all like cucumbers, nor are they edible. By contrast the leaves resemble much the leaves of a kitchen cucumber plant.

Common Michaelmas Daisy

Like dirty snow too early in the year. The banks of the Dordogne are covered in a mass of tiny white flowers. Common Michaelmas Daisy (Symphyotrichum x salignum) is an American and it looks like it is happy to be in France.

It colonizes the banks of rivers. It takes only a few years to cover a whole surface with dense and chaotic vegetation, by means of its rhizomes that go everywhere. An invasive species is supposed to make life difficult for indigenous species, thus Common Michaelmas Daisy is considered to be an invasive. Since 200 years it lives in France, but only recently it spreads really fast. Why? Maybe because the long and warm autumns of the last few years helped it grow and flower during a long time? Should you call it a pest? That would be exaggerated, or?

Large stalks stand up or lay down, here they are draped over a dead branch. They carry loose clusters of composite flowers.

 Ligulate flowers are whitish with often a tinge of pale lilac, and the tubular flowers, nearly invisible in the image, are yellow. The stem is more or less hairy.

In the background you see the trunks of some Ash-leaved Maples (Acer negundo), a very common tree in the river woodlands of the Dordogne. This one is also an invasive species of northamerican origins.

Field Maple

Leaves are turning into gold.

Hera a leaf of a Field Maple (Acer campestre). This tree is easy to find in the wild but it is also often planted. A row of Field Maple make a good hedge and protect against windy weather and it is easy to trim. It is not a difficult tree, it grows on nearly all kinds of soils (maybe with a slight preference for limestone) and supports very well dry summers.

Here it is embellished with spider webs and lichens.

The fruits are called samaras and they are typical for maples. They grow in pairs, every samara carries a wing, and when they fall down together they turn and wheel like little helicopters.

Some branches with summer leaves.

Floating Primrose-willow

It is supposed to be a really intrusive invasive plant, but, no matter, Floating Primrose-willow (Ludwigia peploides subsp. montevidensis) is pretty to look at.

At the end of summer, yes, until in October, it shows off ist yellow flowers. It grows in water or at in places where land and water touch. Here and there it form dense mats of vegetation on the banks of the Dordogne river or even in the water where there is not much current.

Rosettes of leaves detach themselves from the mother plant and float down the river to new spots.

Autumn Squill

On this roadside colours have changed. It is no longer sallow grey and dry yellow.
Many tiny blue stalks appear from the morning fog.

 

Those are Autumn Squills (Scilla autumnalis) and, never seen before, this year there are so many of them they nearly cover the soil. And they are big, most plants have a dozen of flowers or more. Well, big...

You would not think plants like those dry summers. But maybe, in this case, the underground bulbs took some strenght from abundant and long-lasting spring showers? In summer Autumn Squill has no leaves or stems above ground, so possibly it did not suffer thet much from hot sunshine and drought.

A little white plant between hundreds of blue flowers. Why not?
  

The flowers are still closed, waiting for the sun coming through. In an hour they wil open up like little stars, and it will be more easy to see they are real squills.

There are not only Autumn Squils here. Carline Thistle (Carlina vulgaris) and a tiny Rough Marsh Mallow (Althaea hirsuta) are dried out completely and veiled by spider webs. They also are part of the flora of calcareous meadows.

Hop Trefoil

Like everywhere in Dordogne clovers abound. There are about twenty different species, white, pink or yellow. Hop Trefoil (Trifolium campestre) is very common and like all clovers it leaves consist of three leaflets stipulated at its base. It flowers in May and June, and if the summer is not too harsh and dry it will linger on.

Not this summer. It was rather hot and there was virtually no rain in three months. No problem, most plants in this kind of meadow do survive very well and have a full life cycle, flower, and produce  seeds, before the beginning of the dry season. 

See here the result. A meadow in tints of brown and grey from dried and sun-scorched plants. Yes, there is beauty in it, let's admit it...
The scorching changed the colour of the heads of Hop Trefoil, but not their shape. The Hop Trefoil flower heads are round and brown. The fruits are ripe now, but completely hidden in the dead flowers, like with other clovers the petals stay on the plant after flowering.

Some months ago. The banner - the largest petal of the butterfly-shaped flower - is folded backwards and downwards