The cap of Amanita ameripanthera is 54–91 mm wide, tan to brown to dark brown or pale grayish brown at first and fading or becoming brassier, parabolic to convex to planoconvex to planar, viscid and shiny when wet. The cap's flesh is mostly white and yellowish tan under the cap's skin. The cap flesh doesn't change color when cut or bruised. The margin is very faintly to shallowly striate, downcurved at first, and sometimes has a short sterile extension beyond the ends of the gills. The volva takes the form of felted warts and patches that are off-white to pale tan and darken with age; these remnants are flattened and very finely warted (use 10× lens) and are easily lost.
The gills of Amanita ameripanthera are free to narrowly attached, sometimes with faint decurrent lines on the top of the stem. They are close to crowded, off-white in mass, white to off-white or faintly grayish in side view, and unchanging when cut or bruised. The short gills are squarely cut off, sometimes with a narrow tooth along the underside of the cap.
The stem is 54 – 90 × 10+ – 20 mm, white, becoming slightly brown from handling and sometimes silky fibrillose. The stem's bulb is 24 – 31 × 21 – 33 mm and ovoid or turnip-shaped (pointed below). The stem's flesh is off-white, unchanging when cut or bruised, stuffed with firm white material. The membranous, white ring is skirt-like and connected near the mid-stem. The volva is off-white to white and present as a short ring of tissue around the stem's base—suggesting a collar or "rolled sock" of tissue—or as a short free limb (several mm high in dried specimens and standing out around the stem's base) on the top of the bulb.
The odor has not been recorded. The taste is pleasant, according to persons poisoned by ingesting this taxon. POISONOUS.
The spores of this species measure (8.8–) 9.8–14.2 (–16.5) × (5.5–) 6.5–9.2 (–11.0) µm and are inamyloid and ellipsoid to elongate or (occasionally) broadly ellipsoid. Clamps are absent from the bases of basidia.
The present species is frequently found with conifers in western North America (for example, Fir, Pine, Spruce, and Douglas Fir); in some cases, other trees (such as Alder, Aspen, and Oak) may be present where this mushroom is collected. One instance is known of A. ameripanthera occurring in a pure stand of imported Eucalyptus.
The northernmost recorded specimen came from British Columbia. The known limits of distribution to the south are California in the west and New Mexico in the east. The species could well be found outside the current known range. Suitable habitat occurs in montane regions west of the North American Great Plains.
For many years the present species was confused with the European A. pantherina.—R. E. Tulloss & J. E. Lindgren
Tulloss & J. Lindgr. nom. prov.
elision of “America” with panthera, "panther"; hence, “American Panther Amanita”
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where data is missing or uncertain.
The following material is based on original research
by R. E. Tulloss and Janet E. Lindgren.
54–91 mm wide, tan to brown to dark brown (2.5YR3/4-6, 10YR7/4-6, 2.5YR3/4) or pale grayish brown (6D5) at first and fading to brassier than 6C4, parabolic to convex to planoconvex to planar, glabrous, viscid and shiny when wet; context white, sometimes watersoaked above lamellae, yellowish tan under pileipellis, unchanging when cut or bruised, 9–15 mm thick at stipe, thinning evenly to margin; margin very faintly striate to shallowly sulcate, downcurved at first, sometimes with short sterile extension beyond ends of lamellae; universal veil as felted warts and patches, off-white to pale tan, darkening with age, flattened, very finely verruculose (lens), detersile.
free to narrowly adnate, sometimes with faint decurrent line on stipe apex, close to crowded, off-white in mass, white to off-white or faintly sordid in side view, unchanging when cut or bruised, 6–8 mm broad, with fimbriate edge; lamellulae truncate, sometimes with attenuate tooth, ??.
54–90 × 10+–20 mm, white, becoming slightly brown from handling, narrowing upward, flaring at apex, longitudinally striatulate, sometimes silky fibrillose; bulb 24–31 × 21–33 mm, ovoid, occasionally subnapiform (pointed below), not so markedly distinct from stipe in age; context off-white, unchanging when cut or bruised, stuffed with firm white material, with central cylinder 2–6 mm wide, with larva tunnels concolorous; partial veil membranous, white, skirt-like, submedian, occasionally shredding, collapsing on stipe; universal veil as short collar-like roll of tissue or as short free limb (several mm long in exsiccata and standing out around stipe base) at top of bulb, off-white to white.
Odor not recorded. Taste pleasant, according to persons poisoned by ingesting this taxon. POISONOUS.
Spot test for tyrosinase (paracresol) - positive in pileipellis, surface of stipe, center of bulb context, much (not all) of stipe context after 13 min. in old specimen (Tulloss 1-3-87-BS2).
290–350 µm thick in young specimen, with upper layer extensively gelatinized and 70–175 µm thick, with lower layer ungelatinized and 175–220 µm thick, with strongest pigmentation in 65–70 µm immediately below gelatinized layer; filamentous, undifferentiated hyphae 2.0–7.0 µm wide, branching, densely interwoven, dominantly subradially arranged; vascular hyphae 3.0–5.4 µm wide, with knobby outline, infrequent.
filamentous, undifferentiated hyphae 2.0–13.5 µm wide, branching, dominating, interwoven, often in fascicles, occasionally with narrowly fusiform to narrowly clavate to cylindric slightly inflated intercalary cells (up to 21 µm wide), with walls up to 0.5 µm thick, sometimes with yellowish walls; acrophysalides terminal, singly or (occasionally) in short chains, ellipsoid to ovoid to broadly clavate to clavate to narrowly clavate to narrowly fusiform, up to 123 × 34 µm, with walls up to 0.8 µm thick; vascular hyphae not observed.
bilateral, with subhymenial base composed largely of curving slightly inflated elongate to allantoid to clavate to subglobose cells (up to 112 × 20 µm) and branching, filamentous, undifferentiated hyphae, with angle of divergence shallow (not exceeding 30°); wcs = 30–50 µm; filamentous, undifferentiated hyphae 1.2–5.5 µm wide, branching, with ventricose intercalary elements up to 18.0 µm wide within central stratum and in subhymenial base; terminal, inflated cells apparently absent; vascular hyphae not observed.
wst-near = (10–) 20–45 µm and wst-far = 30–70 µm (moderately inflated) to wst-near = 50–70 µm and wst-far = 70–100 µm (well inflated); with plentiful inflated elements, but also with uninflated hyphal segments, with basidia arising from small inflated cells and from short chains of short uninflated hyphal segments or (infrequently) from allantoid cell originating near edge of central stratum.
32–62 × 9.5–12.8 µm, dominantly 4- and occasionally 2-sterigmate, with sterigmata up to 8.0 × 1.8 µm; clamps not observed.
On pileus: gelatinizing at upper surface and there all elements collapsed, with uncollapsed portions pale brown in mass; filamentous, undifferentiated hyphae 3.5–6.5 µm wide, branching, sometimes in fascicles, common; inflated cells dominating, hyaline at first, becoming pale gray by time of pileus separation from partial veil, pale gray to pale brown by onset of sporulation, tending toward periclinal orientation, often smaller near pileipellis, terminal, singly or in chains of 2 or 3, with some such chains having anticlinal orientation, cylindric to fusiform to narrowly fusiform to narrowly clavate (up to 108 × 36 µm), globose to subglobose to broadly ellipsoid to ellipsoid (up to 80 × 53 µm), with walls thin or (more frequently) up to 1.0 µm thick; vascular hyphae 2.4–8.0 µm wide, knobby, branching, locally in complex tangles, plentiful to locally infrequent (absent from all sections in one basidiocarp of Tulloss 3-2-89-E). On stipe base: similar to that on pileus, but with larger and more plentiful fascicles of filamentous, undifferentiated hyphae, with hyphae and inflated cells in approximately equal quantities, with chains of inflated cells often aligned with fascicles of hyphae (sublongitudinally?), with inflated cells somewhat more brown than on pileus; vascular hyphae 3.5–5.6 µm wide, scarce.
longitudinally acrophysalidic; filamentous, undifferentiated hyphae 2.0–10.5 µm wide, branching, plentiful, with walls from slightly thickened up to 0.7 µm thick; acrophysalides plentiful to dominating away from surface, often rounded at septum, sometimes nearly cylindric, up to 280 × 42 µm, with walls up to 1.0 µm thick; vascular hyphae 5.6–11.9 µm wide, uncommon.
filamentous, undifferentiated hyphae 2.1–9.8 µm wide, frequently branching, dominating, often in fascicles, dominantly subradially arranged, with walls thin to slightly thickened and occasionally yellowish; inflated cells narrowly clavate, plentiful, terminal, singly, up to 206 × 21 µm, with walls up to 0.5 µm thick; vascular hyphae 2.4–21 µm wide, with knobby outline, sinuous, scattered to moderately common.
California: Under ?? or under
Pinus and Quercus agrifolia or under
Eucalyptus globulus Labill. (not
Idaho: At 1910 m elev. Under Abies,
Picea, and Pinus ponderosa.
New Mexico: At 2690 m elev. In mixed forest
of Populus tremuloides, Picea,
Abies, Pseudotsuga menziesii,
Alnus, and Pinus ponderosa.
Costa Co. - Hercules,
prop. D. Bojantchev, 2007 Dimitar
Bojantchev s.n. (RET 418-9, nrITS & nrLSU seq'd.),
ii or iii.2008
Dimitar Bojantchev s.n. (RET 423-1, nrITS &
Los Angeles Co. - Santa
Monica Mtns., Malibu Cyn.,
Tapia Co. Pk., 3.i.1987 Barry Silver s.n.
Santa Monica Mtns., Stunt Cyn.,
3.i.1987 Barry Silver s.n. [Tulloss 1-3-87-BS2]
(RET 091-10, nrITS seq'd.).
Monterey Co. - Asilomar Conf.
Ctr. [36°37’13”N/121°56’11”W], 14.ii.1998 coll.
unkn. s.n. [Tulloss 2-14-98-A]
(RET 274-9, nrITS & nrLSU seq'd.).
Orinda Co. - Briones Overlook staging area,
2.ii.2011 Mike McCurdy B-M-A008 (RET 656-4,
nrITS seq'd.); unkn. loc., 25.i.2011 Mike McCurdy
B-M-A 001 (RET 655-10 nrITS seq'd.).
Santa Cruz Co. - Aptos Hills, S border of Aptos,
2.iii.1989 John Feci & R. E. Tulloss 3-2-89-E
(RET 042-3. nrITS seq'd.); Aptos Hills, N border of
Watsonville, 2.iii.1989 J. Feci s.n. [Tulloss
3-2-89-H] (RET 042-1, nrITS seq'd.).
San Francisco Co. - San
Francisco, Land’s End, 6.iii.1982 David C., Mark H.
& R. E. Tulloss & Mycol. Soc. San Francisco
foray participants 3-6-82-A (RET 174-10, nrITS seq'd.),
-B (RET 173-10, nrITS seq'd.),
-C (RET 174-9).
IDAHO—Valley Co. - Payette Nat. For., ca.
McCall, Brundage Reservoir
[45°3.331" N/ 116°6.726" W], 5.ix.2008 Kathy
Richmond s.n. [NAMA 2008-180] (F;
RET 423-9, nrITS seq'd.).
NEW MÉXICO—Taos Co. - 2.4 km N of Red
River on Mallette Rd., 5.ix.1993 R. E. Halling 7115
(NY; RET 115-8, nrLSU seq'd.).
OREGON—Coos Co. - Coos Co. For., Seven
Devils area, 27.iii.1992 Catherine Ardrey 1779 (RET
047-5, nrITS seq'd.)
Co. - Portland, NW Leahy Road, 27.iv.2009 Richard
Tullis s.n. [Janet E. Lindgren 09001] (RET
- Vancouver, Ellen Davis Tr., 30.iv.1990 J. E.
Lindgren s.n. [Tulloss 4-30-90-JEL1] (RET
014-8, nrITS & nrLSU seq'd.); Vancouver, NE
75th St., 27-28.iv.2009 Sue
Aberle s.n. [J. E. Lindgren 09002] (RET
684-10, ITS & nrLSU seq'd.). Unkn. Co. -
unkn. loc., 5.vi.1990 J. & W. Caruthers s.n. [J. E.
Lindgren 90-16] (RET 014-7, nrLSU seq'd.), 7.vi.1990
Janet E. Lindgren 90-20
(RET 015-3, nrLSU seq'd.).
[NOTE: See also Thiers 32154 (SFSU).]
Additional possible reports of “A.
ameripanthera” come from:
BRITISH COLUMBIA—Vancouver, 1.vii.1959 R.
J. Bandoni 494 (UBC).
CALIFORNIA—Mendocino Co. - unkn. loc.,
18.xi.1961 Thiers 882 (SFSU); Trinidad, 5.vii.1935
A. H. Smith 3831 (MICH). San Mateo Co. -
Pacifica, 21.viii.1976 S. Pollock 1325 (DTJ),13223
(DTJ); unkn. loc., 5.ii.1965 Thiers 12170
(SFSU). Sierra Co. - unkn. loc.?,
s.d.? W. J. Sundberg and G. Breckon 356 (SFSU).
WASHINGTON—Unkn. Co. - Olympic Mtns.,
2.xii.1941 A. H. Smith 17515 (MICH).
[Doubtful: Ontario, Pembroke, 26.ix.1968 E. J.
Klatt and J. W. Groves 124783 (DAOM, ?doubtful
A comparison of sporographs for A. pantherina and the present species follows:
—R. E. Tulloss & J. E. Lindgren
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Tulloss & J. Lindgr.
Spore data for collections provisionally identified as: Amanita ameripanthera Tulloss & J. Lindgr.
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.