The information provided below is derived from the original description of Amanita xerocybe and from the revision of Simmons, Henkel, and Bas (2002).
The cap of A. xerocybe is 20 - 67 mm wide, from conico-convex with a broadly rounded apex to convex and soon flattened around a low, obtuse umbo, with a widely sulcate-striate margin (25 - 65% of the radius). The cap is at first sordid whitish to cream, later becoming ochraceous, and at the center, brownish ochraceous yellow to ochraceous brown. The volva is present as cottony-fluffy to powdery-granular substance gilvous to dark red-brown to fairly dark orange-reddish brown patches that covers the entire cap—especially densely over the center. The volva is not easily separated from the cap because the connecting hyphae do not readily gelatinize—hence, the Latin and English names of this species.
The gills are distant, free, somewhat intervenose, broad, whitish but soon becoming cream (particularly on drying). Short gills are very scarce, truncate, sometimes partly adnate to long gills.
The stem is up to 90 × 6 mm, annulate, narrowly stuffed, and gilvous to ochraceous tan. The flesh is creamy to white and unchanging when cut or bruised. The annulus is very fragile and often missing. Volval remnants form a narrow fragmented ring or rings around the upper part of the stem's basal bulb.
Odor and taste were not recorded.
The spores measure 7.8 - 9.1 (-9.7) × 7.6 - 9.1 (-9.5) µm according to Bas (1978) and 6.0 - 9.0 × 6.0 - 8.6 (-9.4) according to Simmons et al. (2001) and are inamyloid and globose to subglobose. Clamps are absent at bases of basidia.
This species is known from Amazonian Brazil and the Pakaraima Mountains of western Guyana. The latter localities include riverine swamp forest and adjacent slope forest dominated by Palywayek (Dicymbe corymbosa) and other mixed hardwoods.
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INPA; isotype L
C. Simmons, T. Henkel and Bas. 2002. Persoonia 17(4): 578, fig. 6(a-e), pl. 7.
The following text may make multiple use of each data field.
The field may contain magenta text presenting data from a type study
and/or revision of other original material cited in the protolog of the present taxon.
Macroscopic descriptions in magenta are a combination of data from the protolog and
additional observations made on the exiccata during revision of the cited original
The same field may also contain black text, which is data from a revision of the present
taxon (including non-type material and/or material not cited in the protolog).
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this text is appropriate.
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 the protolog and from Simmons et al. (2002).
from protolog: medium-sized, fairly slender, fleshy, rather fragile.
from protolog: 40 - 67 mm wide, at first sordid whitish, later becoming ochraceous, at center brownish ochraceous yellow to ochraceous brown [Chipmunk (MP) to Antique Brown (MP) to 10YR 5/6-8 to ca. 7.5YR 5/6], from conico-convex with broadly rounded apex to convex, soon flattened around low obtuse umbo; context ; margin sulcate-striate (0.25 - 0.35R), with marginal ridges 1.8 - 2 mm broad, with edge crenulate; universal veil as subfelted-subflocculose covering breaking up into minute granular-subflocculose "dots," gilvous, especially dense over disc, more sparse at margin, adnate.
from protolog: free, distant, whitish at first, soon becoming cream, in dried specimens cream to buff, somewhat intervenose, broad, with edge minutely subflocculose-subgranular and concolorous; lamellulae truncate, very scarce, at times partially adnate to lamellae.
from protolog: up to 90 × 5 mm, narrowing upward, gilvous to ochraceous tan, in dried material sordid brownish ochraceous, with thin covering of universal veil remnants; bulb as "enlarged" or slenderly fusiform base (about lower quarter of stipe), up to 9 mm wide; context stuffed, white to creamy, unchanging, with narrow central cylinder; partial veil apical, easily separating, deciduous, thickish and fluffy, smooth, concolorous with stipe surface, minutely granular above when dried, felted-subflocculose below when dried; universal veil as narrow fragmented rim around upper bulb (hardly visible when dried).
from protolog: Odor lacking. Taste not recorded.
from protolog: lacking gelatinized suprapellis; filamentous hyphae ca. 3 - 6 μm wide.
from protolog: "very loose and therefore difficult to section when dried."
from protolog: comprising rather small, mostly sphaeropedunculate cells.
from protolog: On pileus: as relatively thin broken layer, with upper three-quarters comprising mainly erect inflated terminal cells, with lower quarter comprising mainly more or less erect hyphae; filamentous hyphae 3 - 8 μm wide, colorless, with thin to slightly thickened walls; inflated cells 28 - 62 × 24 - 54 μm, abundant, broadly ellipsoid to obovoid, more rarely broadly clavate or globose, with brown vacuolar pigment and slightly thickened walls, terminal singly. On stipe base: Similar to material on pileus, with more frequent hyphae and more elongate inflated cells.
from protolog: [longitudinally acrophysalidic—ed.] acrophysalides abundant, up to 280 × 35 μm.
[Note: The surface of the stem in Amanita usually comprises more frequent hyphae than does the interior and has acrophysalides significantly smaller. In the present species Bas notes in the protolog that the latter are sphaeropedunculate to broadly clavate, brownish, and often mucronate.—ed.]
from protolog: two-layered. Upper layer: filamentous hyphae 2.5 - 6 μm wide; inflated cells crowded, globose to ovoid or pyriform, usually pedunculate, pale brown, 28 - 60 μm long, terminal. Lower layer: filamentous hyphae more abundant than in upper layer; inflated cells smaller than in upper layer.
lamella edge tissue
from protolog: as proportionately rather broad, yellow-brown (in NH4OH) strip; inflated cells globose to ellipsoid, of pedunculate, sometimes clavate, 28 - 50 (-60) × 24 - 34 μm, colorless to pale brown, often with slightly thickened walls, sometimes with "pale amorphous substance" on exterior.
from protolog: [10/1/1] 7.8 - 9.1 (-9.7) × 7.6 - 9.1 (-9.5) μm, (Q = 1.0 - 1.05), smooth, with very slightly thickened wall, inamyloid, globose to subglobose, often attenuate toward apex; apiculus "normal or rather broad"; contents mono- to multiguttulate; color in deposit not recorded.
from Simmons et al. (2002): [49/3/3] 6.0 - 9.0 × 6.0 - 8.6 (-9.4) μm, (Q = 1.0 - 1.10; Q = 1.03 - 1.04), smooth, with slightly thickened wall, inamyloid, globose to subglobose; apiculus "normal"; contents not recorded; color in deposit not recorded.
Brazil: "Solitary. On raw humus under trees in campinarana vegetation..., forming ectomycorrhiza with Sapotaceae and/or Leguminosae.
Guyana: from Simmons et al. (2002): In "riverine swamp forest and adjacent slope forest dominated by Dicymbe corymbosa (Paluwayek) and other mixed hardwoods, on sand soils with thick organic accumulations and on exposed sandstone and cliff boulders."
from protolog: BRAZIL: AMAZONAS—rd. from Manaus to Caracarai, km 45, 28.ii.1978 H. St-John & R. Singer B10730 (holotype, INPA; isotype, L).
from Simmons et al. (2002): GUYANA: POTARI-SIPARUNI REGION—Pakaraima Mtns., Upper Ireng watershed - Suruwaburu Crk., 1-2 km upstream from juncture with Jurka R., 2.iii.1997 T. Henkel TH6217 (BRG); ca. Sukabi R., 1-2 km upstream from confluence with Ireng R., 22.v.1998 Terry Henkel TH 6434 (BRG); Mt. Kukuinang, ca. 3 km WSW from peak, 25.v.1998 T. Henkel TH6614 (BRG; L); Upper Ireng R. 0.2-1 km downstream from Kurutuik Falls, 15.ii.1997 Terry Henkel TH6261 (BRG; L).
—R. E. Tulloss
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1. Amanita xerocybe, Pakaraima Mtns., Guyana.
Dr. Terry Henkel - (1) Pakaraima Mountains, Guyana, reproduced courtesy of Persoonia, Leiden, the Netherlands)
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