The following material is based on original research by R.E. Tulloss.
The orange-brown to brown cap is up to 75 mm wide and is darkest over the center. The distribution of pigment over the cap suggests fine radial hairs. The cap is convex with a distinct rounded knob in the center depression. The cap's flesh is white with darker lines above the gills. The cap is 4 mm thick over the stem, thins evenly for more than half of its radius, and then is membranous to its edge. The edge is striate. No volval remnants are present.
The pale cream gills are free and up to 8.5 mm broad. The short gills are cut off squarely or somewhat rounded, are unevenly distributed, and are of diverse lengths.
The off-white stem is up to 161 x 11.5 mm and can become faintly brown from handling. The stem narrows upward and flares at the top. It is almost satiny at its top and has fine fibers near its bottom. The stem's flesh is off-white except where it is darker at the bottom above the base. The stem is hollow with a central cylinder 4.5 mm wide that is lined with wispy white fibers. The volva is sac-like and membranous; its surface and interior are soft and white. The volva is 57 x 21 mm and up to 1+ mm thick. A small internal limb is present at the point of the volva's attachment to the stipe.
This mushroom's odor is indistinct. It's taste was not recorded.
This species was found growing singly at 2800 m elevation in the dark loam of a mixed forest dominated by multiple species of Oak (Quercus), Mexican Weeping Pine (Pinus patula), Sacred Fir (Abies religiosa), a groundsel-like shrub in the Aster family (Baccharis conferta), and the Texas Madrone (Arbutus xalapensis).
This species has also been called "Amanita species M24" by RET in species lists and draft keys.—R. E. Tulloss and N. Goldman
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18.viii.1998 C. E. Skovnik s.n. [Tulloss 8-18-98-C] (RET 293-1)
J. Geml et al., Naturalis Biodiversity Centre, Leiden
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 molecular studies
of Drs. Jozsef Geml and Linas Kudzma and other original
research by R. E. Tulloss.
up to 75 mm wide, orange-brown to brown, darkest over disc and (occasionally) over striations, unchanging when cut or bruised, subvirgate, convex with distinct umbo, becoming planoconvex with umbo in depression, tacky, subshiny; context white with sordid line over lamellae, 4 mm thick over stipe, thinning evenly for 0.65R, then membranous to margin; margin striate (0.4 - 0.45R), nonappendiculate; universal veil absent.
free, ??, pale cream in mass, off-white in side view, up to 8.5 mm broad, broadest at about 0.75 distance from stipe to margin; lamellulae subtruncate to rounded truncate, unevenly distributed, of diverse lengths, infrequent.
up to 161 × 11.5 mm, off-white, becoming faintly brown from handling, narrowing upward, flaring at apex, subsatiny above, finely fibrillose below; context off-white except sordid in region of lower stipe not including base, unchanging when cut or bruised, hollow, with central cylinder 4.5 mm wide and lined with wispy white fibrils; exannulate; universal veil as saccate volva, membranous, white on surface and throughout interior, soft, up to 57 × 21 mm, up to 1+ mm thick, with point of attachment about 0.35 distance from stipe base to highest point of limb, with small limbus internus place approximately at point of attachment.
Odor indistinct. Taste not recorded.
Spot test for laccase (syringaldazine) - completely negative throughout basidiome. Test voucher: Tulloss 8-31-94-A.
Solitary. At 2800 m elev. In dark loam of mixed forest dominated by Quercus spp. with Pinus patula, Abies religiosa, Baccharis conferta, and Arbutus xalapensis.
Toluca - km 22 Toluca-Temacaltepec Rd., El Mapa
[3150 m], 4.vii.1996 Adriana Montoya Esquivel 1544
(RET 252-3, nrITS seq'd.; TLXM). Mpio. Unkn. - Llano Grande,
18.viii.1998 C. E. Skovnik s.n. [Tulloss 8-18-98-C]
(RET 293-1, nrITS seq'd.; TLXM).
Huamantla - El Volcán La Malintzi, La Cañada Grande
[19°14’45” N/ 97°54’56” W, 3110 m], 16.vii.1996 A.
Montoya Esquivel & R. E. Tulloss [Tulloss
7-16-96-C] (RET 256-4, nrITS seq'd.; TLXM), [Tulloss
7-16-96-D] (RET 256-5, nrITS seq'd.; TLXM).
Mpio. Panotla - 1 km E of San
Francisco Temezontla [19°20’41” N/ 98°16’31” W,
2640 m], 17.vii.1996 A. Montoya Esquivel & R.
E. Tulloss [Tulloss] 7-17-96-D (RET 255-7,
nrITS seq'd.; TLXM),
14.viii.1998 unkn. colls. s.n. [Tulloss 8-14-98-??]
(RET ??; TLXM).
Mpio. San Luis Teolocholco - Parq. Nac. La Malinche,
SW slope of La Malintzi volcano [19°13’53” N/ 98°03’59” W,
3250-3290 ], 14.viii.1998 A. Kong Luz s.n. [Tulloss
8-14-98-A] (RET 292-9, nrITS seq'd.; TLXM).
Mpio. Tlaxco - El
Rodeo, Cerro El Peñon [19°41'19" N/ 98°14'02"W,
2775 m], 31.viii.1994 A. Estrada Torres & L.
Varela Fregoso p.p. [Tulloss 8-31-94-A]
(RET 133-9; TLXM),
[Tulloss 8-31-94-G] (RET 133-10; TLXM), [Tulloss
8-31-94-K] (RET 133-6; TLXM), 14.vii.1996 A.
Estrada Torres et al. [Tulloss 7-14-96-C]
(RET 254-3; TLXM).
This species has also been called "Amanita
species M24" by RET in species lists and draft keys.
—R. E. Tulloss
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