Olive text indicates a specimen that has not been
thoroughly examined (for example, for microscopic details) and marks other places in the text
where data is missing or uncertain.
The following material is based on DNA data produced by L. V. Kudzma and other original research of R. E. Tulloss.
61 - 64 mm wide, grayish brown, subvirgate, darker brown (10YR 2/2 or slightly lighter) over umbo, planar with pronounced umbo in central depression, tacky, matte; context white except for thin gray line below pileipellis in disc, 4 - 4.5 mm thick over stipe, thinning evenly for 75 - 85% of radius, then membranous to margin; margin nonappendiculate, striate (0.25 - 0.55R); universal veil absent.
free [sometimes with faint short (<10 mm long) decurrent lines on top of stipe], close to subcrowded, cream to pale cream in mass, off-white to pale creamy white in side view, not staining when cut or bruised, 5 - 6.5 mm broad, broadest at about three-quarters of pileus radius; lamellulae truncate to subtruncate, unevenly distributed, of diverse lengths, plentiful to scattered but not uncommon.
132 - 176 × 9± mm, white to cream, narrowing upward, not or barely flaring at apex, minutely pulverulent near apex, finely longitudinally striatulate, fibrillose where handled, sometimes becoming gray where handled; context hollow, white (except sometimes slightly tannish in very base), not changing when cut or bruised, with no insect tunnels observed, with central cylinder 5 - 6 mm wide, with central cylinder lined with cottony white fibrils having sublongitudinal orientation; exannulate; universal veil as fragile saccate volva, sometimes remaining awhile as complete sac (e.g., 23 × 17 mm), in any case eventually breaking and tearing rather easily and then dividing into thin cup enclosing stipe base and large patches distributed on lower stipe above cupulate portion, soft textured, with exterior surface white with gray spots, with interior surface grayish, with highest point of limb 30 mm from bottom of stipe, with limb < 1 mm thick at mid-height,
Odorless. Taste not recorded.
On pileus: not present in material examined. On stipe base: filamentous hyphae ?? mm wide, fasciculate, organized in irregular lattice enclosing inflated cells, ??; inflated cells ??; vascular hyphae ?? mm wide, ??.
lamella edge tissue
Solitary. Colorado: At 2749 m elev.
Gregarious under Populus
tremuloides. Minnesota: In dark loam of forests
dominated by Pinus strobus, P.
resinosa, Betula, and Populus
In the field the original Minnesota material was
thought to belong in the
"A. rhacopus group." It appears to be
genetically distinct from all the known taxa of
that group. It has been
previously treated in these pages as A.
sp-MN05. The present taxon is listed with
of a group sharing an unusual 5' motif for nrLSU,
on the technical tab of the the page for
We have received nrITS sequences apparently of
the present species from alpine
collections from British Columbia
(courtesy Shannon Berch).
Note: We may have received mixed
collections with regard to RET 572-7. The
photograph shows a white cap and a membranous volval
sac. The material we received produces the DNA
of A. minnesorora, which is brown-capped with a
submembranous to friable volva.]
[Note: RET notes indicate that Pat Leacock may have an
image of RET 156-9.]
Wisconsin: In mixed forest of Betula spp,
Quercus rubra, Picea, Abies, and
WISCONSIN—Unkn. Co. - Lake Lucerne, Ed's Lake Trail [45.53005° N/ 88.84485° W, 500m], 20.vii.2013 Britt Bunyard s.n. [mushroomobserver #140595] (RET 572-7, nrITS seq'd.).]—R. E. Tulloss
Information to support the viewer in reading the content of "technical" tabs
can be found here.
Tulloss and Kudzma
"Minnesota sister ringless amanita"
Spore data for collections provisionally identified as: Amanita minnesorora Tulloss and Kudzma
Each spore data set is intended to comprise a set of measurements from a single specimen made by a single observer;
and explanations prepared for this site talk about specimen-observer pairs associated with each data set.
Combining more data into a single data set is non-optimal because it obscures observer differences
(which may be valuable for instructional purposes, for example) and may obscure instances in which
a single collection inadvertently contains a mixture of taxa.