Hello Nick
I think this will be even more obscure than you imagined. You can see what the Annotateted Checklist meant by IL. I have put together a lot of Massee's publications and a Copernic search has produced nothing about Nectria lagenae; this is all I came up with. Out of interest what led you to the name?

Hi Nick and Chris,

check this:
https://www.biodiversitylibrary.org/page/3085957#page/152/mode/1up

and this seems to be another "IL":
https://www.biodiversitylibrary.org/item/107950#page/244/mode/1up

Update: Frederick William Moore was then Keeper of the Botanic Garden at Glasnevin which houses the National Herbarium as well. Possibly the specimen is preserved there with some additional informations....

Regards
Martin

Ausgezeichnetes archäologisches Graben Martin!
I have done all the excavating I can and cannot trace anything more. Massee described few Nectria spp. and he never completed the "Pyrenomycetes" 5th volume of his British Fungus Flora.
I cannot see anything even where mis-read handwriting may have ended up with this mystery epithet . . .
Chris

Dear Chris,

hard to say if Massee ever published the description of N. lagena(e) elsewhere. Ramsbottom in his obituary (1917) mentions more then 250 papers Massee wrote. Who knows them all?

Best
Martin

Dear Chris and Martin,

Thanks for this excellent detective work.

Yes, an exhaustive search of Massee's publications will be difficult, but just by browsing the titles one can tentatively discount many of them. My initial feeling is that it's an unpublished taxon.

I'm led to believe that Massee wasn't great at keeping herbarium material, so I don't have much hope in there being a specimen at Glasnevin (though I may ask anyway).

Chris - I was asked to resarch this taxon by a colleague who is doing some experimenting with the National Biodiversity Network Atlas. They are currently pulling up random records (not neccesarily mycological ones) and this unexplainable literary record came up.

Cheers,
Nick

Considering Moore's description I wouldn't take this Nectria for an Irish fungus, since it was found on imported bulbs presumably from Costa Rica.
For a similar case see Hennings 1901:
https://www.jstor.org/stable/3993962?seq=1#page_scan_tab_contents

Regards
Martin