Under oaks. These two were found 20 meters apart, I think they are the same because of the slow yellow KOH reaction on the cap and the thick stem. Nearby was also Amanita bisporigera, with a thinner stem and faster KOH reaction.

One of the fruit bodies does not have gills! I have never seen this on Amanita before.


A couple days later
A couple days later

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It didn’t appear to me that the gills had been munched
By: Alan Rockefeller (Alan Rockefeller)
2015-09-09 05:46:10 CST (+0800)

They were evenly deformed, and it didn’t look like the tissue was damaged. It looked more like the gills just never formed.

The last two pics were taken two days later, no signs of gill damage / rotting from being munched was visible there.

I have this dried and might sequence it, though I expect it will have the same sequence as others with normal gills. The two fruit bodies were found about 20 yards apart, so it is possible they are different.

Thank you for calling my attention to this obsevation.
By: R. E. Tulloss (ret)
2015-09-09 05:30:49 CST (+0800)

I can see in the third image that the button has normal gills. There is a small hole in the partial veil.

I have a guess at what happened in the case of the larger specimen. This guess is based on the roughly spiral grooves around the top of the stipe in the gill-less specimen. One or more insects or gastropods got into the large fruiting body in the button stage and preferentially when for vitamin-loaded spores and basidia. The edge gills of the lamellae were also eaten. There is no sign of them left on the upper side of the partial veil or on the stem above the partial veil. A number of amanitas can concentrate heavy metals in the fruiting body, which may serve as a deterrrent for this type of attacke; however, the highest concentration is in the universal veil (in the cases studies), and the second highest concentration is in the pileipellis (again, in the cases studied). There is some concentration of heavy metals in the gills; however, the remainder of the fruiting body apparently lacks this kind of defense. Hence, if a critter goes through the partial veil and can tolerate the relatively low concentration of heavy metals in the gills, it can be party time.

Schizohymenial development is fundamental to Amanita (with nearly a 1000 species known). I suspect that development of the gills got under way as normal. But somebody (or some bodies) found a picnic waiting.

Very best,