Is identifying the genus of a fungus (mushroom specifically) enough?

Question

Does the genus of a mushroom have enough information about it, without the species?

Let's say I wanted to identify a mushroom (when picking) to see if I can safely pick and later eat it. Let's say I successfully identified the mushroom's genus (using an identification key guide book such as this one). Is this enough to determine whether or not the mushroom is edible? Is it enough to determine other general information about it? Furthermore, is it enough to determine whether it is good-to-eat (as in not bitter)? For example, I know that some edible mushrooms have other mushrooms very similar to them that are not edible or that are bitter and difficult to cook.

In other words, are there any genuses of mushrooms that generally are recognized as edible but in reality contain both edible and inedible species of mushrooms in them?

Answer 1

Again, I would say: no, genus is not enough.

Another example: boletes (specifically, genus Boletus).

According to Wilderness College:

One of the most common and well-known groups of edible wild mushrooms are the boletes or boletus species (Boletaceae) ...

But

Many species in this group are edible, with only a handful being poisonous. The poisonous boletus species have red or deep orange pores. Outside of the few toxic species, some species of boletus are bitter or inedible.

For example, see here for a list of edible boletus mushrooms (e.g., B. edulis), while some examples of Boletus species to avoid include: B. huronensis and B. satanas

An additional issue to classifying all species in a genus as "safe to eat," is that our classifications are not always reflective of real taxonomic associations. In other words, some groups are not monophyletic and their evolutionary (and therefore physiological/nutritional) characteristics should not be assumed to originate from the same common ancestor .

This is apparently true of the boletes. From Wikipedia:

Boletus has been found to be massively polyphyletic, with only a small percentage of the over 300 species that have been assigned to Boletus actually belonging there and necessitating the description and resurrection of many more genera

• See for example: Nuhn et al. (2013)¹

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^{1: Nuhn, M.E., Binder, M., Taylor, A.F., Halling, R.E. and Hibbett, D.S., 2013. Phylogenetic overview of the Boletineae. Fungal Biology, 117(7-8), pp.479-511.}

Answer 2

It seems like the simple version of your question is: can anyone come up with even one example of 2 fungi species in the same genus in which one is edible and the other is not?

Here's one example:

The genus Amanita.

This genus contains about 600 species and contains some very toxic species -- in fact, it's often considered one of the most deadly genera of mushrooms in the world. The reason? Two "species" alone account for a large majority of mushroom-related deaths world-wide each year: the death cap (A. phalloides) and numerous species each colloquially named destroying angels (e.g., A. virosa, A. bisporigera, A. ocreata and A. verna) in their own geographic regions.

However, A. caesarea, commonly called Caesar's mushroom, is edible despite it being in this "deadly" genus. From Wikipedia:

Amanita caesarea, commonly known as Caesar's mushroom, is a highly regarded edible mushroom in the genus Amanita, native to southern Europe and North Africa. This mushroom can also be found in La Esperanza, Honduras, where a festival is celebrated annually in its honor. While it was first described by Giovanni Antonio Scopoli in 1772, this mushroom was a known favorite of early rulers of the Roman Empire.[1]

See here for further discussion and details.