I also considered P. michelli, but not everything is correct for me. First of all, the habitat. I have seen them in damp places, but usually on the ground, not on the roots. Another detail that doesn't suit me is the asci length. So long for this species ????
I would, however, think more about P. limnaea, although the ornamentation is quite unusual. Considering, however, that this species is very changeable, maybe this collection could temporarily qualify for it?

I had a similar problem with them so I put them temporarily separate on my site;
http://www.grzyby-pk.pl/gat_p/gat_peziza_limosa.php

The article, the title of which is given in the comments, shows the variability of ornamentation.

We've also recently discussed another collection that is very close to P. limnaea:
http://www.ascofrance.fr/search_forum/64027

If something more could be said about it, it would definitely be useful to have more data, as mentioned by Josep. Texture view would be nice too!
best regards
Mirek

Hola Josep y muchas gracias por tu respuesta. Si no te importa os contesto a ti y a Mirek a continuación, sobre su comentario. Muchas gracias y saludos.

Mirek, Josep, el habitat no es sapróito, sino que estaban creciendo sobre arena, ayer estuve de nuevo y encontré 2 ejemplares más, aqui podréis verlo claramente.
A mi tampoco me parece P.michelii, especialmente por la ornamentación. Con respecto a las P.limnaea que yo he recolectado en varias ocasiones no me parecen las mismas; aunque la que comenta Mirek, sobre la que se discutió en este foro como especie próxima a P.limnaea, veo que la ornamentacion se parece bastante.
Co respecto al tamaño de las ascas, podreis ver en las nuevas fotos la desproporción con respcto al tamaño de las esporas, y se trataba de un ejemplar maduro.

Mas fotos micro.

Sorry, I have no more ideas :(
Maybe check out Nicolas' work:
Note sur une pézize rare, Peziza badioides (Pezizales), retrouvée en Savoie.
Available at: https://www.researchgate.net/publication/270157986_Note_sur_une_pezize_rare_Peziza_badioides_Pezizales_retrouvee_en_Savoie
There are many comments in it about the different genres.
However, the content of spores (drops) does not suit me for the species mentioned there. The ornamentation is also a bit different?

Although I like Peziza, it is not an easy topic, at least for me.
best regards
Mirek

Conozco ese trabajo, y lo he consultado, de hecho P.badioides fue mi primera opcion, pero ni el tamaño de las ascas, asi como la de las esporas me cuadra con esta especie. Tal vez haya alguna sugerencia mas.
Muchas gracias Mirek, 
Un saludoANtonio

Hi Antonio
That is why I proposed P. Limnaea. I am not saying, however, that it is this species, but most likely closely related to it.
I based my decisions on a few details that fit P. limnaea:
- the dimensions of the spores are appropriate
- spores contain drops also suitable for this species
- ornamentation in this species is very variable, as researchers of this type claim
- the habitat as appropriate
Now you've added a photo of textures. Note that there are pear-shaped cells in medulla. I have seen such in my fruiting bodies of this species. If you want to compare it on my website with this species, photo no. 19.
http://www.grzyby-pk.pl/gat_p/gat_peziza_limnaea.php
The spore ornamentation is different, but on this page collections with the typical characteristics of P. limnaea are selected. Others, similar, have separate sides ... you can compare.
Mirek