This description is taken from the original description (Bas, 1982). The cap of A. pulverotecta is 150 mm wide, plano-convex, dry, with a sulcate-striate margin (15 - 25% of the radius). The cap is whitish but densely sprinkled with pale buff powdery remnants of the volva.
The gills are just touching the apex of the stem, moderately crowded, and whitish with a yellowish buff tinge.
The stem is 175 mm long, broadening downwards, and exannulate. It has a somewhat elongated, subventricose bulb at its base. The flesh is white, soft, and brittle. The volva is completely pulverulent.
The odor and taste of this mushroom were not recorded.
The spores measure (10.6-) 10.9 × 12.8 (-14.8) × 5.7 - 7.4 µm and are inamyloid and ellipsoid to elongate to elongate-ovoid (infrequently cylindric). Clamps are absent at bases of basidia.
This species was originally described from Malawi. The only habitat information recorded is the species' occurrence at about 1,000 m elev.
This species is unusual in section Amanita because of its lacking a true skin on the cap. The volva remains connected to the cap because there is no gelatinized region in which hyphae connecting the volva to the cap could be severed—as would commonly occur in the majority of amanitas. The present species is separated from A. farinosa Schwein. (in which gelatinization is considerably delayed) and related taxa by lack of a distinct skin on the cap and by more elongated spores, among other characters.—R. E. Tulloss
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The following material is derived from the protolog of the present species.
from protolog: Basidiome large and robust.
from protolog: 150 mm wide, whitish, plano-convex, perhaps with slight central depression (per exsiccatum), dry; context white, soft, brittle; margin sulcate-striate (0.15 -0.25R in esxiccatum), slightly inflexed (per exsiccatum); universal veil as dense thin covering of pale buff pulverulence, over disc pulverulent-granular.
from protolog: barely touching stipe apex, moderately crowded (per exsiccatum), whitish with yellowish buff tinge, up to 16 mm broad, with conspicuous minutely flocculose white edge (per exsiccatum); lamellulae only one found in exsiccatum "and that truncate."
from protolog: 175 mm long, gradually broadening downward into bulb, probably whitish, covered with grayish powder; bulb subventricose, 27 mm wide, with short radicating point (ca. 30 mm long in exsiccatum); context solid, white, soft, brittle; exannulate; universal veil as grayish powdery to powdery-subsquamulose material, with squamule-like fragments < 1 mm, "completely pulverulent".
from protolog: as ungelatinized, cutis-like layer, brown in exsiccatum probably from necropigment, between universal veil and pileus context; filamentous hyphae 3 - 7 μm wide, interwoven to subradially arranged. [Note: Probably with hyphal interconnection to universal veil largely unbroken at maturity.—ed.]
from protolog: bilateral, divergent; "difficult to analyze in dried material."
from protolog: ca. 30 - 40 μm wide; "almost" pseudoparenchymatous, "consisting of inflated ramose to (sub)globose cells."
from protolog: On pileus: disordered; filamentous hyphae 2.5 - 5.5 (-7) μm, entangled, slightly thick-walled, incrusted, yellow-brown; inflated cells globose to ellipsoid to (more rarely) elongate, 28 - 46 × 20 - 35 μm, yellow-brown, with somewhat encrusted walls, terminal singly or (sometimes) in short chains. On stipe surface: like tissue on pileus, but without incrustation; inflated cells with only slightly thickened yellowish walls.
from protolog: comprising external (lower) amorphous gelatinized layer of disintegrating tissue (up to 200 μm thick) and interior (upper) layer of inflated elements; inflated cells abundant, small to relatively large, thin-walled, colorless, clavate to ellipsoid to globose, 15 - 45 × 20 - 30 μm, terminal singly or in short chains; clamps absent.
from protolog: [10/1/1] (10.6) 10.9 - 12.8 (-14.8) × 5.7 - 7.4 μm (Q = 1.60 - 2.0; Q = 1.75), hyaline, colorless, smooth, thin-walled, inamyloid, elongate, sometimes narrowing toward apiculus, sometimes with slight suprahilar depression; apiculus rather broad, truncate, subapical; contents usually monoguttulate ("oil drop" type), "somewhat greenish in NH4OH"; color in deposit not recorded.
from protolog: At about 1,000 m elev. Terrestrial.
from protolog: MALAWI: Malose Mtn., Zomba Plateau, 21.iii.1980 B. Morris 186 (holotype, K).
from protolog: "The non-amyloid spores in combination with the sulcate-striate margin of the pileus and the bulbous base of the stipe render this species a member of section Amanita. There are a number of species in this section that have with A. pulverotecta a character in common that is somewhat unusual in Amanita, viz. a dry powdery or granular pileal surface caused by a pulverulent volval layer over a non-gelatinizing pileipellis. In addition the volval remnants on the base of the stipe are usually also pulverulent or granular and sometimes not or hardly discernable in mature carpophores.
"It was precisely this set of characters that lead Earle (1909: 449) to create the genus Amanitella for the North American species Amanita farinosa Schwein. We know now that several other species show these characters also, e.g., A. obsita Corner & Bas (Malaya), A. subvaginata Cleland & Cheel (Australia), A. xerocybe Bas (Brasil). It is tempting to bring these species together in a taxon on subsectional level, but unfortunately among themselves they differ rather strongly in other aspects, such a very small, globose versus large, ellipsoid spores, annulus present or absent, etc. Moreover, some brightly coloured species like A. bingensis Beeli ([Democratic Republic of ] Congo) might have to be placed in the same group and it seems that among these the transition from a dry pileipellis with adnate pulverulent volval remnants to a more or less gelatinized pileipellis with small, friable, wart-like volval remnants is very gradual.
"It is not clear yet which characters should prevail in subdividing section Amanita.
"Among the species in section Amanita with a dry pulverulent pileal surface, A. pulverotecta is easy to recognize by its large (>10 μm) ellipsoid spores and its large and robust fruit-body."
Bas did not often describe the surface of the stipe other than describing volval material (perhaps associated with a limbus internus) that might be distributed on it. The stipe surface in many species is similar to the interior of the stipe, but with fewer and smaller acrophysalides and with a tendency to become gelatinized by maturity of the basidiome. In the protolog of the present species, Bas described the stipe surface in general and in the specific region near the apex. In the general description he says the surface consists of rather loose acrophysalidic tissue." However, the stipe surface near the apex was covered with more specialized tissue: "with crowded sphaeropedunculate, piriform and clavate terminal cells, 35-150 × 28 - 46 μm." This tissue includes cells ranging from the size and shape of moderate-sized acrophysalides to the size and shape of inflated cells of the lamella edge tissue in this and many other amanitas. It is possible that Bas was describing the "stipe side" of the lamella edge tissue of the present species. This tissue (if the just-state hypothesis is correct) may be described here for the first time in the history of Amanita studies. The editors would be very interested to know of other cases.
Encrusted cells in the universal veil in section Amanita are now known from three taxa—A. sinensis, A. nehuta, and the present species.
—R. E. Tulloss
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