Observation 26278: Amanita onusta (Howe) Sacc.
When: 2009-10-03
No herbarium specimen

Notes: I found this beauty on a well-rotted log in a hardwood forest. Its cap measures 4.5cm, the stem 7cm, the flesh .5cm and the gills 1.2cm. The cap is convex with distinctive dark olive-brown warts, the largest occurring at the top. The warts are particularly striking, very angular, structured rather like crystals. The margin and narrowly attached gills are covered with white powdery veil remnants. Each gill is separated by a partial gill extending 1 to 1-1/2cm from the margin. The upper 1cm of the centrally positioned, straight stipe has a white powdery sheath, discolored to a golden brown at its lower edge. Under the sheath, the stem is creamy to light tan, darkening slightly toward the slightly enlarged base. It is covered in white powder, but handling gave the stem more of a scaled or striated appearance. The bright white mycelia are very fine and have a tenacious hold on the dirt/wood bits.

The spores are white to very pale grey. I could not measure them, but most appear nearly round or elliptical.

I didn’t notice a distinctive odor in the field, but it started to get a bit nasty 48 hours later and to leave brown moisture on the spore print paper. No chance I’ll save this one!

Proposed Names

89% (2)
Eye3 Eyes3
Used references: Mushrooms of Northeastern North American, Bessette, Bessette and Fischer
Mushrooms of North America, Phillips

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
You’re welcome.
By: R. E. Tulloss (ret)
2009-10-06 15:14:54 BRT (-0300)

You’re welcome.


Thank you!
By: Fran Sheldon (Serendipity Fran)
2009-10-06 14:52:48 BRT (-0300)

Credit really belongs to my friends at Northeast Mushrooms (http://groups.yahoo.com/group/NortheastMushrooms/), Bill Yule and Dick Grimm who suggested this ID. I had been trying to ID it as something other than an amanita because the gills seemed to me to be firmly attached to the stipe. A beginner has many lessons to learn, which is why I appreciate so much your explaining that spore prints may contain cells other than spores, especially in the amanitas. Thank you! -Fran

It looks like you nailed this one…
By: R. E. Tulloss (ret)
2009-10-06 13:23:18 BRT (-0300)

Nice description, too.

You have to be careful about spore print color in amanita because cells on the gill edges often have a pigment similar to that of the volva. There are three sorts of cells on the gill edge that can come off on your spore print: cells from the partial veil (annulus) (if there is one), spores from the part of the universal veil (volva) that was originally positioned between the developing gills and the developing stem in the “button” of the mushroom (primordium), and finally the specialized cells along the gill edge that allow the gill edge to separate from the stipe or annulus or volva that was adjacent to the gill edges while it/they were forming in the button.

The anatomy is very cool and very unique to Amanita because of the way an Amanita button develops (i.e., differently from all other agarics).

Very best,


Created: 2009-10-05 21:59:42 BRT (-0300)
Last modified: 2009-10-05 21:59:42 BRT (-0300)
Viewed: 132 times, last viewed: 2016-10-23 07:46:54 BRST (-0200)
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