Do you know which is this small flower in Asturias?
It is an Erythronium lily commonly called a "dog's-tooth-violet" or "trout lily". I see that one of the species Erythronium dens-canis is found in Spain, being native to Europe. Most of the Erythronium species are native to North America. The foliage is very attractive and they are commonly grown as ornimentals. The flower in your photo is just opening. I have included a few links that better describe these lilies.

https://en.wikipedia.org/wiki/Erythronium

https://en.wikipedia.org/wiki/Erythronium_dens-canis

http://www.srgc.org.uk/bulblog/log2008/160108/log.html