> What Irish mushrooms should I go hunting for this season?
There's at least 300 species of edible fungi in Ireland, nearly all of which are covered in my book (subtitle is "a forager's guide to the wild fungi of Britain, Ireland and Europe). (https://toptalkedbooks.com/amzn/0857843974)
Every year is different, so I can't tell you which particular species will have a good year in 2018. But the mushrooms often do well after a hot summer.
> I'm interested in the origin of this huge cultural difference. Is there a geographical / biological reason for this?
There a whole section of my book about this (Chapter 5 of the introductory section, on culture and laws). There is a link between language families and attitudes to fungi (including which edible fungi are preferred). Which suggests very old cultural differences. I do go into this at length in the book, and can't do so here because people are posting questions at the rate of two or three a minute...
>>Are there more toxic mushrooms in the north west, and more tasty >>ones in the south and east? Or is it purely cultural?
It is purely cultural.
You need my book. It tells you everything you need to know, from absolute beginner to expert. Best book on this topic ever published, by a long way. Covers everything of relevance in Norway: