Gyromitra sect. Discina in Europe

During spring, you might find so called "Pig's Ears" growing on dead wood or directly on the ground, brownish cup fungi that get spread out flat when ripe and belong to genus Gyromitra, the "False Morels". The problem with IDing Pig's Ears is that there are more than just one species and that those species look nearly identical to each other. In the past, it was quite easy to identify them to what was believed to be species level at the time: Pig's Ears growing on dead deciduous wood were called Gyromitra parma and those growing on dead conifers were called Gyromitra perlata (or Gyromitra ancilis; those two names are synonymous). But in 2009 it was shown by VAN VOOREN & MOREAU that the situation is unfortunately not that easy. Now there are about ten possible species in Europe: G. perlata (syn. G. ancilis), which is probably still the most common species, G. geogenia, G. intermedia, G. warnei, G. fluctuans, G. megalospora, G. olympiana, G. accumbens, G. leucoxantha and the mainly American species G. convoluta. Without microscopy, it is only possible to ID them to subgenus level on inaturalist: subgenus Discina. (In subgenus Discina there are two sections, sect. Discina and sect. Pseudogyromitrae with Pig's Ears belonging exclusively to sect. Discina, so you could ID them to section level, but as those sections do not currently exist on inaturalist, this information might be a bit superfluous. The information that subgenus Discina will sometimes be treated as its own genus, which makes the Pig's Ears Discina sect. Discina, might also be a bit superfluous, as inaturalist still considers Discina a subgenus of genus Gyromitra.)

If you have a microscope and want to ID them to species level, you can use the literature linked below. Unfortunately, I have not found an English key until now, only a typification of the most common species G. perlata (syn. G. ancilis). If you know an English key or any other useful current literature in your European language of choice, especially about distribution, please feel free so to post a link in the comments so I can add it to the literature list. Linked to this journal entry, there is also an observation of G. perlata including microscopic images you can compare with.

If you have valuable information to add, please do so in the comment section. Just because I'm writing this journal entry doesn't mean I'm the leading expert on those fungi.

Literature:

English: