Congratulations, Cj, on the Giant Puffball! Haven't found this one yet, only smaller puffballs (e.g. Common Puffball, Lycoperdon perlatum). If they are older, the solid white interior becomes yellow, loses its structure and is then not edible anymore. If it was still like tofu, I guess it was the right time for harvesting!
This field guide (thank you for the link, Bethanny) might be usable as a start. The instructions in the beginning are good and the photos a good lead, but the species descriptions are not sufficient to determine edible mushrooms. The authors warn on several places about eating uncertain mushrooms, but don't provide this certainty in determination. A feature that is present in the field guides I know, but missing in this one, is a segment about "mistaking possibilities" (I don't know if this is the best way to phrase it in English) on each mushroom page. There, species with similar appearance are mentioned and how to distinguish the two from each other. If I know "oh, I can mistake this mushroom only with this other one and these are the differences", it gives the necessary certainty to collect them. I admit, this is probably more difficult to achieve over such a large area like the US. Regional field guides might be more useful with that.
Some additional thoughts I had, when I flipped through the pdf:
- Nobody I know of is doing spore prints here, although the spore color is a good attribute. I'll pick that up...
In nature the spore color can sometimes be seen already before collecting, on material below the caps. For instance when mushrooms are growing in groups or tufts, on the caps of the lower ones.
- Among all the warnings about Amanitas, nobody seems to mention, that Amanita pubescens (Blusher, we call it Pearl Mushroom) is a very good edible mushroom. Not so much for beginners because of the scary sisters (or brothers, whatever
), but actually nicely distinguishable. The Blusher is growing more often in forests here, than all the toxic Amanitas together. "Blusher" is actually a very good name, because it describes the attribute that all the toxic Amanitas don't have: It becomes red on cuts, bruises and on places after pressure. Also, its cap has red areas on top, but a pale Fly Agaric can look similar, so the red blushed sites on stem and gills are the best way to distinguish it. No toxic Amanita blushes, their flesh stays white!
I'm collecting Amanita pubescens since I was nine (I had an excellent mentor at this time) and it is worthwhile, because they can become quite large and grow in every type of forest. In the US everywhere east of the Rocky Mountains, according to mushroomexpert.com.
There are two other edible Amanitas with gray caps (Amanita excelsa and Amanita vaginata), but they are harder to distinguish from the Panther Cap (Amanita pantherina) and I don't collect them.
- Also, they warn in the book strongely about the genus Cortinarius, which I can only understand as a warning to beginners. About 70% of this large group are edible species, a bit slimy sometimes, but often in beautiful colors (and the slimy skin can be stripped). I collect sometimes as an addition Cortinarius violaceus, muscigenus and mucosus. The taste of them alone is not great (a bit earthy), so it should be a mixed meal with other mushrooms. The danger to mistake Cortinarius traganus (which is only medium toxic, according to my books and wikipedia) or the two very toxic ones, Cortinarius rubellus and orellanus, for them is relative... It's a very large group though and definitely one of the more difficult ones.