When I looked into this question in 2014, I encountered a difference of opinion  with some authors considering the two species as distinct and other authors considering M. chateri a synonym of M. cornubiensis.

Hello Andreas,

M. greletii (syn. of M. flavorubens) and M. scotica (syn. of M. contorta) are being kept separate in IF too, although they were synonymized earlier (M. greletii in Korf, 1971, Some new discomycete names, Phytologia 21(4): 204; M. scotica based on type study in Yao et Spooner, 1995, New combinations in Melastiza and Scutellinia (Pezizales), Mycotaxon 53: 469). Also, when Moravec in 1994 changed Melastiza to subgenus of Aleuria he combined most of the then known Melastizas to Aleuria. In IF, some of the names from his paper have current name in Aleuria (boudieri + carbonicola), some in Melastiza (cornubiensis + flavorubens + rubra). I would be very glad, if anyone can explain why.
 

Interesting case is the IF synonymy of Melastiza flavida (current name Peziza aurata, according to IF):
http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=413752
http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=362334

As far as I understand it there are several taxa involved:
1. Aleuria flavida (K.S. Thind & S.C. Kaushal) J. Moravec, syn. Melastiza flavida K.S. Thind & S.C. Kaushal
- This is a small Melastiza, spores 16-19 × 10.8-13 um with rather coarse ornamentation. (see Moravec 1994)

2. Peziza subcitrina (Bres. in Rehm) Korf, syn. Plicaria subcitrina Bres. in Rehm., Humaria subcitrina (Bres.) Sacc., Aleuria subcitrina (Bres. in Rehm) Boud.
- I don't have any informations about this taxon at hand. It was combined to Peziza by Korf in Mycotaxon 14:1-2 (1982), who cited basionym only. The other synonyms (combination into Humaria and Aleuria) are cited in Spooner et Yao, 1995, Notes on British taxa referred to Aleuria, Mycol. Res. 99(12): 1515-1518.

3. Peziza aurata (Le Gal) Spooner & Y.J. Yao, syn. Aleuria aurata Le Gal
= Aleuria cerea var. flavida (W. Phillips) Boud., syn. Peziza micropus var. flavida W. Phillips, syn. Peziza flavida (W. Phillips) M.M. Moser ex D.C. Pant
- The synonymy of these two taxa, Le Gal's A.aurata and Phillips's var.flavida, although unnoticed by IF, was published in Spooner et Yao (op.cit.) It is a Peziza with amyloid asci and smooth spores 16-20.5 × 8-10 um. They wrote that the combination into Peziza at species rank given in Moser (1963 - I don't know this work) and Hohmeyer (1986) was invalid since they didn't cite the basionym. It seems Yao and Spooner were probably not aware of the article by D.C.Pant (1993, The genus Peziza in India - new records, Journal of Mycopathological Research 31(1): 21-23) where the Moser's combination P.flavida was validated (according to IF; I don't have that article). On the other hand, Le Gal's A. aurata was published in 1941, long before the combination by Moser.

I'm not aware of any paper making the(se) amyloid Peziza(s) conspecific with a Melastiza but I certainly don't know all related literature, so perhaps... 

Viktorie 

I think it is important to realise that Index Fungorum is a nomenclatorial database (undermanned/staffed) and that the associated Species Fungorum is an only partly managed taxonomic opinion database. There are endless discrepancies between generally accepted synonymies and those shown in the Species Fungorum. Where mistakes are found in the IF-part, I recommend writing to Poul Kirk with the corrections. Currently I think PK cannot handle the SF part  - too much work involved. All that is published on online on IF is automatically accepted as current, and that could also be debated...

cheers

Thomas makes a very important point re the differences between IF & SF. In my experience Paul Kirk has acted quickly and positively in making changes I have suggested if the reasons why (indicating published papers etc.) are presented. Species Fungorum is very behind the times when dealing with the "honorary fungi" which constitute the Peronosporaceae for example see:
http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=157515

Less helpful, in my opinion, is the way in which Species Fungorum points every infra-specific taxon to the parent species (as can be seen in the link above). Sub-species, varieties et al. disappear, but can be particularly important categories when dealing with, for example, plant pathogens - Mycobank keeps them separate.

amitiés
Chris