Collection location: Palikea-Palehua Trail, Honolulu, Hawaii, USA [Click for map]
Observed growing in mixed native and alien tropical insular lowland mesic forest, in ironwood (Casuarina sp.) litter at the base of a mossy rock face on the west side of the trail. Images recorded but no measurements made; specimen not collected. Following description compiled via inspection of images:
Cap depressed (sunken), cream to light yellow color with narrow flattened margin. Gills light yellow, close, probably attached, adnate. Stalk equal, possibly with cup; texture rough, possibly abraded.
Bears at least superficial visual resemblance to pictures of Amanita marmorata var. myrtacearum in Hemmes and Desjardin, .
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Thanks for the link to Amanita austrostraminea. I checked it it and found that one of the images at http://mushroomobserver.org/140574?q=2USz6 appears quite similar to one of my images at http://mushroomobserver.org/191982?q=2UM0V.
Obviously, that “discovery” is not specifically relevant to this observation.
The number of amanitas in Hawaii is small but growing. All of the taxa reported so far have been imported with trees (as symbiont) or with soil (as a saprophyte that happened to be present).
I can think of four or five taxa that have been found in Hawaii that can be assigned to Amanita (this is from memory). At least one was first recognized from material collected and posted on MO—-A. austrostraminea. You might want to look at the several images of that on MO. Text is here:
Thanks for taking the time to provide such a detailed explanation. I not only learned that whatever the visual similarities between images of this observation and images of Amanita marmorata var. myrtacearum, they do not provide the basis for suggesting an ID in this case, but I also learned why not.
As a matter of intellectual curiosity, I re-examined the cited image in Hemmes and Desjardin. I have scanned it and uploaded it as the third image of this observation. (I do not believe doing so violates copyright, as the intended use of the scan/copy is for academic purposes.) Having been enlightened by your description, I knew what to look for and immediately noted marbling on most caps. The individual mushroom in that image that I thought looked similar to mine is the second from the left, cap at upper left, in which the marbling is not obvious, but in which the general color and cap shape seemed interestingly similar to my observation.
As to Amanita or not, I got a suggestion in another forum that this observation might be Amanita. My only reference for Hawaiian mushrooms () is a popular rather than an academic resource, and not encyclopedic. It only lists two Amanita species, of which the habitat for A. marmorata var. myrtacearum includes Casuarina forests, in one of which I made this observation. Thinking wishfully, I then saw something that wasn’t there.
Meanwhile, thank you very much, I’ve also increased my descriptive vocabulary with the addition of “floccose” and of projecting or sterile margin, the latter categories I did not find in any of my reference materials or in online searches.
Finally, lest I write into next week, I’ll end by noting that I have no immediate prospect of returning to the controlled access area where I made this observation, but I shall in future attempt to collect specimens of each observation unless I am in a locale where such activity is specifically prohibited.
The color of the cap could also be described as gray becoming bleached in the center or cream becoming gray toward the margin. The margin is what is often called “projecting” and “sterile” because it appears to extend beyond the hymenial surfaces of the gills.
The name marmorata means marbled. This is because the pigment of the cap is distributed in a random manner that the human eye perceives as wiggily lines of color criss-crossing over a pallid background. The color is a monotone ranging for from light brown to medium gray. Genetics suggests the material from New South Wales is the same genetic entity as the specimens found in South Africa (where the name Amanita reidii was introduced and in the Hawaiian Islands (where the material was arbitrarily named as a subspecies of marmorata). In other words, the cap color varies a bit, but the evidence to date supports treating all of the material as one taxon without infraspecific subdivisions.
Images from New South Wales and Hawaii can be found here:
Getting beyond this background information, the mushroom is then unlikely to be marmorata for reasons of pigment distribution on the cap and because of the absence of a persistent skirt-like partial veil on the stem and because of the presence of white floccose material on the stem.
If we could see the stem base, we would also have additional information that might help. Amanita marmorata is a species of section Phalloideae and would have a distinct bulb at the base with a membranous universal veil attached and having free membranous flaps projecting upward from the bulb.
If it is possible to collect and dry this material, I’m sure that there is more that can be said of it.
Perhaps someone who knows more of the Hawaiian mycota may suggest that it is not an Amanita.