The information on this page is derived from
(Lamoureux 2006) and
from original research of RET.
The cap of Amanita subnigra is 40 - 80 mm
wide and dark yellowish brown to ochraceous brown
to somewhat olivaceous
dark brown to brown black.
Sometimes darkest over the center and in a zone at
the inner ends of the marginal striations. At
first it is ovoid to rounded-conic to bell-shaped;
it becomes flattened convex and umbonate. Its
flesh is white except for a brown line below the
cap's skin (most
noticeable above the stem); the flesh does not
stain or bruise. Its edge bears long radial
grooves that extend for 35 to 45% of the cap's
radius. No remnants of the volval are
present on the cap.
The gills of this species are free, crowded, pale
grayish to whitish to cream to slightly orangish
cream in mass and cream in side view. They
do not stain or bruise; the are up to about 4 mm
broad at three-quarters of the gill length from the
stem. They have a white minutely powdery
edge. The plentiful short gills are truncate to
subtruncate, unevenly distributed, and of diverse
The off-white to cream, ringless stem of A.
subnigra is 60 - 140 × 5 -15 mm, narrows upward,
smooth to satiny or decorated with scattered
Its flesh is white to off-white and stuffed
becoming hollow (with central cylinder
5+ mm wide).
The soft, membranous, sack-like volva (35 × 33 mm)
is white and
sometimes bears scattered brown or ochraceous
spots on its exterior.
truffle-like fruiting body
double click in markup mode to edit.
This species is odorless. Its taste has not
The spores of A. subnigra measure 10.0 - 11.4
(-12.4) × (8.1-) 8.5 - 9.8 (-11.0) μm and are
subglobose to broadly ellipsoid to ellipsoid and
inamyloid. Clamps are absent from bases of
This species is known from the Island of Newfoundland,
the Province of Québec, and the U.S. state of
Minnesota. Lamoureux reports it from Spruce
(Picea) plantations. It also is found on
limestone barrens possibly associated with
Balsam Fir (Abies balsamica) or Spruce and
in humus of mixed forest including Red Pine (Pinus
resinosa), Birch (Betula), and Poplar
(Populus), with some Black Spruce (Picea
mariana) bogs.—Y. Lamoureux and R. E. Tulloss
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 derived from (Lamoureux 2006) and original research by R. E. Tulloss and Linas Kudzma.
Lamoureux (2006): 40 - 80 mm wide, dark yellowish brown to brown black, sometimes darkest over the disc and in a zone at the inner ends of the marginal striations, ovoid to rounded-conic at first, umbonate when expanded (plano-convex); context white; margin long-striate; universal veil absent.
RET: 55 mm wide, dark brown (somewhat olivaceous?) over disc surrounded by ochraceous brown (10YR 6/4) zone, dark brown over striae at first (fading to a lighter brown), campanulate becoming broadly campanulate; context white except brown line below pileipellis (especially noticeable in disc), sometimes with watery line at juncture with lamellae, unchanging when cut or bruised, 3 mm thick, thinning evenly for 75 - 90% of gill length, then membranous to margin; margin nonappendiculate, striate (0.35 - 0.4R); universal veil absent.
RET: free without decurrent line on stipe apical region, crowded, cream to slightly orangish cream in mass, cream in side view, unchanging when cut or bruised, 4 mm broad, broadest at three-quarters gill length from stipe, with white minutely pulverulent edge; lamellulae truncate to subtruncate, unevenly distributed, of diverse lengths, plentiful.
Lamoureux (2006): 60 - 140 × 5 -15 mm, whitish, smooth or slightly fibrillose; context white, stuffed becoming hollow; exannulate; universal veil as membranous saccate volva, white, sometimes scattered brown spots on exterior.
RET: 117 × 10 mm, off-white to cream, staining/bruising not observed, narrowing upward, not or barely flaring at apex, somewhat satiny, faintly longitudinally striatulate (10× lens); context off-white except gray at very base, unchanging when cut or bruised, hollow with some regions lightly packed with white cottony fibrils, with central cylinder 5+ mm wide, no insect tunnels observed; exannulate; universal veil as saccate volva white, soft, firm, membranous, 35 × 33 mm,1 mm thick at mid-height of limb, with strong ochraceous staining in numerous spots, cross-section revealed no distinct limbus internus.
Lamoureux (2006): Odor indistinct. Taste not recorded.
RET: Odorless.Taste not recorded.
?? × ?? μm, 4-sterigmate, ??, clamps not observed.
composite of data from all material revised by RET: [40/1/1] 10.0 - 11.4 (-12.4) × (8.1-) 8.5 - 9.8 (-11.0) μm, (L = 10.7 μm; W = 9.0 μm; Q = (1.08-) 1.10 - 1.34 (-1.36); Q = 1.20), hyaline, colorless, smooth, thin-walled, inamyloid, subglobose to broadly ellipsoid to ellipsoid, adaxially flattened; apiculus sublateral, cylindric; contents granular to mono- to multiguttulate, with additional mall granules; white in deposit.
Prov. Québec: Under Picea, particularly in
plantations. Sometimes the sole species of
section Vaginatae in such plantations.
July to September. Rare.
RET: Prov. Newfoundland and Labrador, Canada: On
limestone barrens, possibly associated with Abies
balsamica or Picea.
Minnesota, U.S.A.: Solitary. In humus of mixed
forest including Pinus resinosa, Betula,
and Populus, with some Picea mariana
"The dark coloring of the cap is very typical; gray
caps have never been seen on this
taxon. ... Renée Lebeuf photographed this
species in 2005 among spruce; the cap color in her
photographs is in perfect accord with [the cap
color] in our own collections."
RET: The nrITS sequences derived from all non-QU&3acute;bec
collections (Tulloss ) are very good matches to the
sequence derived from Lamoureux 2197. Further
data is being sought.
For a short time, the temporary code Amanita
sp-MN04 was used on this site—based on the
Minnesota collection of the present species.
The following collection has an nrITS sequence that
is an identical match for that of A. subnigra.
However, its nrLSU sequence is not a good match for that
of the present species. This raises the question of
whether the data suggests that multiples species could
share the same nrITS sequence or whether there has been
a failure of the nrLSU locus to
homogenize in the present species. Further
research is required.
Co. - Holy Cross View, 16.viii.1997 M. Horman s.n.
[Tulloss 8-16-97-A] (DBG; F; RET 266-5, nrITS and
Translation from French by RET, who is responsible for all errors.—R. E. Tulloss, Y. Lamoureux, and L. V. Kudzma.
Information to support the viewer in reading the content of "technical" tabs
can be found here.
"Lamoureux's Dark-capped Ringless Amanita"
Spore data for collections provisionally identified as: Amanita subnigra Lamoureux
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.