Observation 138672: Amanita frostiana (Peck) Sacc.

Growing on ground under conifers. Cap 3.5 cm, orange/yellow with red/orange disc, striate margin, yellow warts. Gills whitish, free and close. Stem 8 cm x .5 cm whitish, tapered at apex, ring remnant present, white bulb with yellow/white collar (1.5 cm in diameter). I don’t have Melzer’s to determine whether the spores are amyloid or not, which I know is the definitive test to differentiate between A. frostiana and A. flavoconia, but the striate margin, presence of collar and small size of this specimen seems to point to the former though I know it is rarely found.


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We obtained (in the last two days) a nice “barcode” sequence from this material.
By: R. E. Tulloss (ret)
2014-11-13 23:03:21 CST (-0500)

Thank you again for sending us specimens.

Very best,


Thanks, Naomi
By: Terri Clements/Donna Fulton (pinonbistro)
2013-07-10 15:31:35 CDT (-0400)
Thanks Teresa,
By: groundhog
2013-07-10 13:05:42 CDT (-0400)

This material has been recieved and accessioned into Rod’s herbarium.
-Naomi (working with Rod)

By: Terri Clements/Donna Fulton (pinonbistro)
2013-07-05 12:54:39 CDT (-0400)

Rod, I cut the FB longitudinally as you suggested. I can’t get a good measurement of the thickness of the cap above the stipe. The distance from the bottom of the cap to the top of the bulb is 8 cm. The length of the bulb is 18 mm. Stem width mid height is 6 mm. Bulb width at widest point is 15 mm. As I mentioned this specimen was picked 7/4/13 pm and it was measured on 7/5/13 late am so these measurements may be slightly light due to FB shrinkage.

The bulb in your last pic is clean…
By: R. E. Tulloss (ret)
2013-07-05 11:15:43 CDT (-0400)

as far as I’m concerned. We have some collections from distant places that we were very glad to get; and, to determine them correctly, we had to use pins to chip away the hard soil covering the bulb. It was worth it, however. Take a look at the bulb on A. eriophora:


The dried specimen we received had the stem in a depression at the top of the bulb that was bowl-like. We would never have seen that if we had not slowly picked off the grains of soil from the dried material.

Very best,


You’re welcome.
By: R. E. Tulloss (ret)
2013-07-05 11:07:09 CDT (-0400)

Not all of the soil needs to come off if there is a danger that part of the bulb will break off with it.

I suggest cutting the specimen in half longitudinally for drying. This also will give you the opportunity to divide the height of the mushroom into three parts: (1) thicknes of the cap above the stipe, (2) distance from the bottom of the cap’s flesh to the top of the bulb, and (3) length of the bulb. My length data is organized this way for as many species as possible (sometimes the data doesn’t exist. Width of the stem at mid-height and width of the bulb at its broadest point are two other measurements that are a lot easier to make when the stem is cut in half longitudinally. A sharp razor blade may be required.

Very best,


Thank you, Rod
By: Terri Clements/Donna Fulton (pinonbistro)
2013-07-05 10:54:35 CDT (-0400)

Yes, I would be happy to send it to you. I haven’t dried it yet but will today. Should I remove the dirt/debris from the bulb before drying it?



Very nice, Teresa.
By: R. E. Tulloss (ret)
2013-07-05 10:45:01 CDT (-0400)

I agree with your “by sight” determination.

Would you be willing to send a part of your dried material to us for study?

Very best,

Rod Tulloss

Created: 2013-07-05 10:12:20 CDT (-0400)
Last modified: 2017-06-22 21:07:27 CDT (-0400)
Viewed: 160 times, last viewed: 2018-11-18 09:54:04 CST (-0500)
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