How do people define these 2 types and what are the differences! I think of them all as "Fungi", maybe "macro Fungi", with visible fruiting bodies.
I would argue that "Mushrooms and Toadstools" is more a commercial phrase for book titles than anything else. A title such as "Mushrooms and Toadstools of Britain" would probably sell better than "Macrofungi of Britain".
Yes, they are macrofungi. Or if one wants to refer to macrofungi with a stalk, a cap, and gills underneath the cap, there is the word "agaric".
"Agaric" can be related to the taxonomic grouping, the order Agaricales, though there are a couple of problems with this now. There are a few macrofungi that have the "agaric" morphology but are not in the Agaricales or especially closely related; they have arrived at the similar morphology by convergent evolution. Examples include the chanterelles and Paxillus.
Also, the DNA guys have confirmed what many suspected - there are morphologically quite different fungi that actually belong in the Agaricales, including some of the fairy-clubs (e.g. Clavaria), the true puff-balls, and even a few tiny cup-fungi that look like the ascomycete cup-fungi until one cuts a section.
So maybe "agaric" is no longer so clear-cut and "toadstool" is useful after all. In traditional British usage, a "mushroom" is edible and generally a member of the genus Agaricus, while anything else, inedible or poisonous is a toadstool. But there are poisonous members of the genus Agaricus and other agarics that are edible. And "mushroom" may have wider usage elsewhere (USA I think) and really there is no viable distinction. In classification terms Agaricus is simply a genus within the toadstools in which several species are considered edible by most people. [Not actually by me - cooked mushrooms are nasty-tasting, vile objects that I cannot understand that anyone wants to eat.]
There was a famous court case on this a number of years ago. Knorr used (and still do I believe) Boletus edulis in their "Mushroom soup". They were prosecuted but won their case. So B. edulis is legally a mushroom in the UK.
So "agaric" is a good word, "macrofungus" is often better, "mushroom" is pretty much what you make of it.
And there is, of course, a place reserved in Hell, with extra-hot irons, for anyone who calls these things "shrooms".
Many thanks your thorough explanation! I think you are right that books titled "Mushrooms and Toadstools ...." are more commercial and more recognised by the general public.
I'll try and look up the Knorr court case - I use their mushroom stock cubes sometimes!
I am only an amateur with macrofungi and as with most subjects "the more I know, the more I realise I don't know"!
The more I know the more I realise I don't know
I've often wondered about the difference between toadstools and mushrooms but never got round to enquiring, so thank you for asking the question, Mark.
Thank you Alan, for that excellent explanation. I didn't know about Knorr's court case nor which 'mushroom' was used for their soups.
"So B. edulis is legally a mushroom in the UK."
I think a lobster is legally an insect in Scotland, so quoting the law as a taxonomic authority may not always be wise.