European Umbrella Milkwort

 

We are at the end of october but when you look at this field you could think it is May, so many flowers!

Most of them are species that flower as well before as after the drought and hotness of summer, and the little bit of rain that has fallen since then is enough for them to flower. The clovers grown here for fodder are definitely a minority.

 

 

 

In this field on sandy soil on the edge of a Sweet Chestnut forest a small flower with unusual colours is very obvious.

 

 

European Umbrella Milkword (Tolpis umbellata) is an Asteraceae. In its flower heads we see pale yellow radiating flowers around a dark red heart.

 

 

Every ligulate flower has only one petal fringed at its end. The exterior ligulate flowers are much larger than the lemon yellow and red interior ones. The pistils are nearly invisible in the picture, they are hidden in the flowers. Only some small spots of yellow pollen are visible.

 

The flowers in the flower head are surrounded by bracts that have all the same length and are covered by grey felt hairs. A second row of longer and irregular bracts form a kind of crown under the flower head. A bit lower on the stem also some bract-like leaves can be seen.

 

 

European Umbrella Milkwort is a mediterranean plant and it is not often found in Dordogne, it is at the limit of its area. You could think that with climate change it could become more common here. That's not sure at all, to flourish it needs agricultural fields on sandy soil without herbicide and fertilizer. And this type of habitat is disappearing in Dordogne.

 

 

 

Annual Ragweed

 

It is a beautiful plant, Annual Ragweed (Ambrosia artemisiifolia). It comes from the Americas and it feels at home in France. A bit too much, you could possibly say. Some years ago it was nowhere to be seen, and now it is everywhere.

 

It grows upright like a small Xmas tree with many branches, and every branch carries a lot of flowers.

 

 

The red colour of those branches nicely contrasts with the tender green of the fern-like leaves and the tiny pale flowers.

It is a monoic plant, which means it has flowers with pollen and flowers with pistils but no flowers with both. Here above the male flowers just begin to loose the yellow pollen. Some female flowers with long white protruding pistils are also visible. The pollen is dispersed with the wind.

It is an annual plant that can form large colonies. Her grows Annual Ragweed in a cereal field after harvest. The seeds have germinated in spring and began to grow somewhat later than the cereals. When the combine harvester passed the little plants were too small to be damaged by it. After harvest there was no longer any competition from the cereals and they could grow fast and big.

 

In Septembre the field turned yellow, not because of the hot and dry weather but because of a herbicide treatment the farmer put in place to get rid of weeds. It worked very well, there are not many plants alive anymore on the field. With one exception: Annual Ragweed plants are still green and producing a lot of seeds.

If coming spring the circumstances are favorable, those grains will germinate. They need a well-worked soil with only little competition from other plants. The farmer will do what he can to achieve this. He already killed other plants, and with his next passage with tractor and harrow he will break up the soil. Thus a good seed bed will be prepared. Ar the same time he will scatter the seeds, not only in this field but also elsewhere in other fields. This is very effective because modern tractors do much more kilometers a day as those of our grand-parents. A good crop of Annuel Ragweed is almost guaranteed.

Di farmers really want to cultivate Annual Ragweed? Of course not, this plant is not useful for them and unedible for humans or animals. Its pollen is allergenic and a single plant can produce a lot of it. In a few years, Annual Ragweed can cover a large surface and thus prevent other, more desirable, plants to grow. It is not sensitive to frost nor to drought and it can survive under many circumstances. In short it is a nuisance for the farmer. Moreover, there is a legal obligation to destroy it and do do what one can to eradicate it.

Is it possible to eradicate it? Maybe, but then farmers really need to dedicate themselves to the task. Chemical destruction is difficult - Annual ragweed is resistant to many weedkillers - and only useful when done at the right moment, before the plant begins to produce seeds. The same for mechanical destruction by mowing or crushing that should be repeated often to avoid re-growth. To grow a perennial crop that covers the soil as alfalfa or clover can help but then there are no cereals or corn.

Is it advisable to eradicate it? In any case there will be a lot of collateral damage. While destroing Annual Ragweed you also destroy other species living in the fields. Plants, among which rare species that need a specific habitat, insects, soil species and all life that depends on them. There is a reason why the number of swallows is going down so fast! Also, it happens rarely we manage to eradicate an invasive species even if we really do our best. To mention a few well-known exemples: There are still rabbits in Australia and Asian hornets are still in expansion in France. Same story for Japanese Knotweed or Water Primrose, to mention some plants. There is no reason at all to assume it would be different for Annual Ragweed.

A real conundrum.

What to do (or not to do) with Annual Ragweed and other exotic and invasive plants?

Good question...

Thornapple

In this arable field  grew about 130 different species of spontaneous plants. Mostly those 'weeds' were messicoles, plants with a life cycle adapted to cereals. Most of them were small or very small, nearly invisible between the triticale stalks.

Now everything has changed. Some years ago the tenancy has been taken over and the new tenant and this farmer uses different techniques. As a consequence the weeds have changed also. The smaller messicoles are gone and other species appeared, big vigourous plants that occupy a lot of space. There are only about thirty different species now, but those are present in large amounts. They are very competitive annual plants that grow fast when there is a lot of nitrogen in the soil, and they multiply quickly. They profit from circumstances fit for corn or sunflowers or another row crop where a lot of fertilizer is used. Because those weeds are less sensitive as other spontaneaous plants to herbicides or fungicides they can survive for a long time even in intensively treated fields.

 

  

A beautiful exemplar of Thornapple (Datura stramonium) grows here. A small plant newly germed when the triticale was still  growing, became after harvest in just a few weeks a big plant.

 

Here a colony in a corn field. Thornapple is part of the Nightshade (Solanaceae) family, and like many other Nightshades ot is very poisonous and farmers don't like to have it in their fields. But it is not easy to get rid of it.

 

The big flowers open only in the daytime. They are trumpet-shaped with pointed leaves, very decorative.

Also the spiny fruits are decorative. They contain many black seeds that easily disperse and germinate. Everywhere, not only in cultivated fields but also in ruderal spots.

At the end of the season most of its leaves have fallen and only the skeletal branches are left. Surely a tractor brought the seeds, in the mud on its wheels or in its wagon with rubble and sand.

 

Common Cudweed

It is not exceptional at all when a plant adapts itself to a life near us, humans. Agriculture created possibilities for many wildflowers. The tilling of the soil at regular intervals eliminates competion from other plants for space, food, water and light and softens up the soil so seeds can germinate and form roots more easily.

Common Cudweed (Filago pyramidata) grows in agricultural fields, in fallow lands and in habitats that resemble those. Apparently it has some resistance against herbicides and fungicides commonly used in cereal fields because they are quite common. For that matter, the harvested field here is organic.

Common Cudweed is a rather stiff plant with at the end of every candelabra-shaped branch a round head with small yellow flowers.  It is grey-green, stalks and leaves are covered in felt-like hairs that protects them against drying out and maybe also agains predator insects.

Like all plants of the Composite (Asteraceae) family it has composite flower heads. In this case they are doubly composite. Whzat you see is a round ball with small yellowish pointed structures.

 

 

Every yellow point is a flower head of about 5 mm lenght with some tubular flowers surrounded by green bracts and spiderweb-like hairs that give it a felty appearance. Twenty or thirty of those flower heads for a round ball wuth at its base two or three larger bracts.  And every plant can carry dozens of those balls. How many flowers produces Common Cudweed? May be hub=ndreds, with also hundreds of seeds to give it a good chance for dispersal and survival.

This makes it different from the 'real' messicoles, plants from arable fields completely adapted to cereal cultures, with a life cycle with the same periodicity as cereals and not many seeds, often the same size as wheat so they can be harvested and sown with them.

 

In a field left fallow for a year many different plants grow. Between the Fescues (the long blond grasses) you can see yellow Saint-John's-worts and also big tufts of Common Cudweed.

Here, Common Cudweed has dried out even if it is surrounded by a lot of still green plants.  Why is it already nearly dead? I don't know. The field is dry and poor, destinated to become a truffle plantation. Also this year there were weeks with a lot of rain but also weeks with very hot and dry weather, and many plants grew faster and taller than usually. Maybe Common Cudweed has made already his seeds and now it has decided its season is over before summer. We cannot ask it.

 

Black Spleenwort

After a year and a half, here again plants portraits from Perigord in this blog.

 

Ferns are spore plants. In their life cycle very small plantlets called prothalli develop from spores. The prothallus does not look at all like a fern as we know it. Structures for sexual reproduction, also very small, grow in its surface and after fecundation the sporophyte, the 'real' fern, the plant we recognize easily as such, begins to growis born. If the fern is mature it begins to produce spores and the cycle can start again.

Most ferns need humidity in the prothallic stage, without moisture there cannot be fecundation. No problem in mointainous areas with shadowy slopes and lots of water flowing over rocks, but here in Dordogne where water seeps away through porous limestone it can be more complicated.

So Perigord is not especially rich in ferns. But especially in wooded valleys there are beautiful spots full of ferns. Like here below, on an old path where the remains of the stone walls that bordered it once are still visible.

 

Here we see many 'tongues' of Hart's Tongue Fern (Asplenium scolopendrium), in the centre on top of the 'wall' a bunch of simple divided fronds of a Polypody (Polypodium sp.) and a bit more to the right smaller and thinner fronds of another fern, Black Spleenwort (Asplenium adiantum-nigrum).

Here is its portrait in spring when the new fronds emerge. Black Spleenwort (Asplenium adiantum-nigrum) has black stems and twice-divided pinnate fronds.

 

It grows in deciduous woods, especially Oaks and Hornbeams, but also in mixed forests with Sweet Chestnut, and sometimes it accepts places where there is sunshine during a part of the day.

 

It does not need much soil, a hole in a wall is enough! To grow, Black Spleenwort prefers places not completely horizontal, but generally it does not want complete verticality.

 

This elegant and subtle fern is never more than half a meter high. 

 

 

Besides a forest track under Downy Oaks, Black Spleenwort has grown into a big colony. In May some of last year's fronds were still present but they turn yellow and will soon be gone.