Vitamin D2 + D3 per 100g portion of mushrooms, according to this website from the USDA Agricultural Research Service (https://fdc.nal.usda.gov/)

- Mushrooms, raw: 0.2 µg (7 IU)

- Mushrooms, Chanterelle, raw: 5.3 µg (212 IU)

- Mushrooms, enoki, raw: 0.7 µg (29 IU)

- Mushrooms, maitake, raw: 28.1 µg (1123 IU)

- Mushrooms, morel, raw: 5.1 µg (206 IU)

- Mushrooms, oyster, raw: 0.7 µg (5 IU)

- Mushrooms, portabella, raw: 0.3 µg (10 IU)

- Mushrooms, shiitake, raw: 0.4 µg (18 IU)

- Mushrooms, white, raw: 0.2 µg (7 IU)

As you can see, there are many types of mushrooms and most of them do not have much vitamin D. Some do, but unless you are a mushroom nerd you are getting the wrong kind.

Young adult daily recommended dose = 1000 IU

Just came across this fascinating review:

https://fungi.com/blogs/articles/place-mushrooms-in-sunlight...

267,000 IU after exposing mushrooms to 14 hours of UVB?

Holy cow.

So, much like humans, mushrooms produce vitamin D from sunlight?

How much vitamin D is in a mushroom is going to depend more on how they are grown and stored then on the particular species afaik (in particular how much uv radiation it is exposed to).

I believe also that there will be more vitamin D in mushrooms that are irradiated to give them a longer shelf life. I don't think usa is a country where that practise is common, but i believe it is common in some other countries.