Hi Natha,

In Bauernblatt 11may2002, Dr. Jürgen Eigner writes a long feature on V. riviniana ("Das Hain-Veilchen") in Schleswig-Holstein, which includes:
"besiedelt. Das Hain-Veilchen kommt fast in ganz Europa vor, nördlich reicht die Verbreitung bis in die Tundra
am 66. Breitengrad und südlich bis ans Mittelmeer bis Portugal und Madeira." (The article includes a rather nice photograph of an orange-tip butterfly feeding on V. riviniana flowers.)
[http://www.umweltdaten.landsh.de/nuis/upool/gesamt/bauernbl/hainveilchen_110502.pdf]

The other species similar to V. riviniana in Europe (eg. V. mauritii) do not extend as far as Madeira, apart from V. reichenbachiana, maybe - I have not been able to determine if V. reichenbachiana occurs there.

But there is another species similar to V. riviniana which does occur in the N. African islands - V. anagae, for which David Scott provides us a photo -
http://homepage.ntlworld.com/david.scott40/ct/ct031231.htm.
That plant was photographed in Tenerife, though...
It is named after the Parque Natural de Anaga, in Tenerife, where it is endemic and protected. It has also been called V. anagensis. Gerd Knoche kindly sent me some seed, but it failed to germinate for me. He described it to me on 25jun01 as "a nice late flowering species (just in flower now) and maybe an evergreen version of Viola riviniana."

And V. riviniana occurs in Tenerfie [http://plantsdatabase.com/commentsbyuser.php?user=Monocromatico].
So if V. riviniana occurs in Tenerfie and Madeira, maybe V. anagae does as well?
It is not supposed to (since it has been described as endemic to Tenerife), but just maybe...?

Note: in Portuguese, V. riviniana is called "violetas bravas".

So, in summary:
- your plant is probably V. riviniana
- I can't rule out V. reichenbachiana (but you may be able to - from the sepals or other flower features)
- there is a very small chance it may be V. anagae (it would be an important new location for it)

I hope this helps,
All the best,
Mike

Thank you very much Mike!!
So it is definitively Viola riviniana...It is different from Reichenbachiana that I know and also from V anagae that I used to grow but wich died out quickly :-(
Cheers ;-)

Jolly good.