Using that rule of thumb, you would successfully avoid Amanita virosa (destroying angel), but you could still get poisoned by Amanita phalloides (death cap) which has a pale-green cap.

I don't endorse any rules-of-thumb for foraging, but a much better differentiator for beginners is whether the mushroom has pores vs. gills under the cap. There are virtually no deadly varieties that have pores.

> There are virtually no deadly varieties that have pores.

Never heard this one before. Adding it to my bug out notes. Thanks!

Note that there's at least one, and that a number of them will still make you sick.

Put a few common pored edibles (Laetiporus sp., Cantharellus sp., Grifola frondosa, etc.) in your notes for sure though, with basic descriptions, as even their few remote lookalikes (at least pored ones -- some people think Omphalotus sp. look like Cantharellus for some reason) are just going to give you a moderate stomach upset at worst, and may be edible themselves.

> Put a few common pored edibles (... Cantharellus sp

Chantarelles don't have pores?

Derp; I meant non-gilled. Thanks for the correction. The false gills on chanterelles are a major part of why they're so accessible to new foragers.

They’re not deadly but there are quite a few ones with pores that will make you very sick.

I avoid white and white-ish (i.e.: green-white). It significantly a but not totally- reduces the risk in my area.

Everything else a good book for identification. If its not 100% clear that it is editable, it gets thrown away.

The parasol mushroom [1] is one of the most popular foraged mushrooms in my part of the world and is white-ish.

[1] https://en.wikipedia.org/wiki/Macrolepiota_procera