The following description is based on the original description of Ridley (1991).
The cap of Amanita nehuta is
25 - 65 mm wide, plano-convex to plano-depressed, buff, non-viscid,
with a striate margin. The pale greyish sepia to fuscous volval
remnants are pulverulent on the center raised into wart-like peaksor
warts or radial ridges. The volval remains long attached to the cap. The
flesh is white, with a very pale area under the skin in the center.
Gills are crowded, free, 6 - 7 mm wide, white to pale buff; the
short gills are subtruncate.
Its stem is 20 - 75 × 4 - 11 mm, hollow,
exannulate, with a smooth to subfloccose upper stem and smooth lower
stem. The surface is white, very pale buff, or very pale grayish
sepia. The basal bulb is clavate to bulbous, 10 - 16 mm in diameter.
The base has a rim or band of powdery volva, the same color as on the
cap. The stem has no ring. The flesh is white, sometimes streaked with
pale gray or buff.
The spores measure 6.5 - 9 × 5.5 - 8 (-8.5) µm and are subglobose
to broadly ellipsoid to ellipsoid and inamyloid. Spores from the
paratype measured by RET produced the following: 6.5 - 7.6 (-8.4) x
5.6 - 6.7 µm. Clamps are absent at the bases of the basidia.
Originally described from Wellington, New Zealand, associated with many types of Nothofagus
(Southern Beech), leptospermum, and kunzea. Known from both North and
South islands of New Zealand. Ridley points out the similarity of A.
nehuta to A. farinosa Schwein., A.
obsita Corner & Bas, A. subvaginata (Cleland
& Cheel.) E.-J. Gilbert, and A.
xerocybe Bas. All these species appear to have a cap surface that
gelatinizes late in development so that the volva remains intimately
connected to the cap skin well into maturity of the fruiting body. For this reason, the cap often remains
powdery looking well into maturity.
A character observed by RET in several of Ridley's cited collections is the fact
that the inflated cells of the volva in this species are at least
sometimes warted. A character very rare in the genus Amanita.—R. E. Tulloss
G. S. Ridl.. 1991. Austral. Syst. Bot. 4: 351, fig. 3(a-h).
The editors of this site owe a great debt to Dr. Cornelis Bas
whose famous cigar box files of Amanita nomenclatural information
gathered over three or more decades were made available to RET for computerization
and make up the lion's share of the nomenclatural information presented on this site.
nehu (Maori), "dust"—referring to the pulverulent volval remnants on the pileus of the present species
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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 predominantly based on the protolog of the present species. Some additional data (as marked in the following) is based on original research by R. E. Tulloss.
from protolog: Basidiomes very small to medium.
from protolog: 25 - 65 mm, buff, plano-convex to plano depressed, non-viscid; context white, very pale grey beneath disc; margin sulcate (0.17 - 0.38 R); universal veil pulverulent, pale grayish sepia to fuscous, on disc raised into wart-like peaks, or radial ridges.
from protolog: free, crowded, white to pale buff, 6 - 7 mm wide, margin laciniate; lamellulae subtruncate.
from protolog: 20 - 75 × 4 - 11 mm [length includes bulb], white or very pale buff or very pale grayish sepia, with upper portion smooth to subfloccose, with lower part smooth; bulb 10 – 16 mm wide, small but pronounced or simply clavate; context white, streaked with very pale grey or buff, hollow; exannulate; universal veil as grayish sepia to fuscous pulverulence forming ridge or band around top of stipe's bulb or around clavate stipe base.
from review of paratype by RET: 50 - 105 µm thick; ungelatinized surface layer of colorless, filamentous, undifferentiated hyphae extending upward into and confluent with universal veil, sometimes reduced to irregular dense turf-like layer of broken and collapsed stubs (even then, not gelatinized); intermediate layer of colorless, partially gelatinized, filamentous, undifferentiated hyphae (0±-) 10 - 50 µm thick; subpellis of ungelatinized filamentous, undifferentiated hyphae, yellowish, 25 - 60 µm thick; filamentous, undifferentiated hyphae ?? µm wide, ??; vascular hyphae 5.6 - 10.2 µm wide, sinuous, sordid yellow, crossing back and forth between pileipellis and universal veil.
from protolog: 31 - 54 × (8.0-) 9.0 – 13.0 (-14.0) µm, 4-spored, rarely less than 4-spored; clamps absent.
from protolog: On pileus: filamentous hyphae moderately abundant, 6 - 12 µm wide, umber, finely encrusted, irregularly arranged; inflated cells abundant, umber, finely encrusted, globose to ellipsoid, 18.5 - 92 × 13.5 - 92 µm, either single or in chains. On stipe base: not described.
from review of paratype by RET: On pileus, exterior surface: ??. On pileus, interior: filamentous undifferentiated hyphae 3.7 - 6.5 µm wide, common, strongly yellow to pale yellowish to sordid pale yellowish to colorless and hyaline, branching, locally entangled, sometimes constricted at septa, with walls thin or up to 1+ µm thick, with surface often decorated with densely placed raised punctation, sometimes subrefractive and then with thickest walls; inflated cells dominating, terminal singly (or possibly in short chains?), ellipsoid to broadly clavate to broadly fusiform to subpyriform, up to 70 × 54 µm (excluding decoration), with walls thin (occasionally) or up to 1+ µm thick and hyaline and colorless to yellow (when walls thickened), with surface often decorated with densely placed raised punctations and flat irregular warts up to 2.9 µm wide at widest point, with dark yellowish brown to brown contents; vascular hyphae not observed; clamps not observed. On pileus, lower surface: with colorless hyaline hyphae from pileipellis confluent with basal hyphae and inflated cells, with vascular hyphae as described for pileipellis. On stipe base, exterior surface: ??. On stipe base, interior: ??. On stipe base, inner surface: ??.
lamella edge tissue
from protolog: Inflated cells globose to ellipsoid to clavate, thin-walled, hyaline, 8 – 23 × 5.5 - 14.5 µm, in short chains of up to six cells, easily detached.
From protolog: [312/26/-] 6.5 – 9.0 × 5.5 – 8.0 (-8.5) µm,, (Q = 1.06 - 1.33; Q' = 1.16), hyaline, thin-walled, , inamyloid, subglobose to ellipsoid; apiculus not described; contents not described; white in deposit.
from revision of paratype by RET: [20/1/1] 6.5 - 7.6 (-8.4) × 5.6 - 6.7 μm, (L = 7.2 μm; L’ = 7.2 μm; W = 6.2 μm; W’ = 6.2 μm; Q = 1.08 - 1.25 (-1.28); Q = 1.16; Q’ = 1.16), hyaline and colorless to subopaque and pale yellow, thin-walled, smooth, inamyloid, subglobose to broadly ellipsoid, adaxially flattened; apiculus sublateral, cylindric; contents multiguttulate to granular; white in deposit.
From protolog: Solitary to subgregarious. Under Nothofagus fusca, N. menziesii, N. solandri, N. truncata, Leptospermum scoparium, and Kunzea ericoides. Known from the North and the South Islands of New Zealand.
from revision of paratype by RET: In Nothofagus litter [in addition to the above].
From protolog: NEW ZEALAND: AUCKLAND─Bombay Hills, Mt. William Track, 17.iii.1979 M. Taylor s.n. [G. M. Taylor 1106] (paratype, ??); Waitakere Range, Spragg’s Bush, 3.v.1978 W. Versluys & P. Johnston (paratype, PDD 'GR8'). NELSON─Karamea, Umere, 8.i.1969 R. F. R. McNabb s.n. (paratype, PDD 31273). OTAGO─Dunedin, Mt. Cargill Scenic Reserve, 26.ii.1989 G. S. Ridley 618 (paratype, DD 56160). WELLINGTON─Rimuaka For. Pk., Orongorongo Track, 8.iv.1987 G. S. Ridley 398 (paratype, PDD 56159); Orongorongo Valley, Paua Ridge, 25.iii.1987 G. S. Ridley 341 (holotype, PDD 56157), 8.iv.1987 G. S. Ridley 390 (paratype, PDD 56158). Wairarapa, 2.xii.1950 G. Stevenson 782 (paratype, K 36090, mixed collection).
from revision of paratype by RET: NEW ZEALAND: WELLINGTON—Wairarapa 2.xii.1950 G. Stevenson Cone 782 (paratype, K 36090, mixed collection).
—R. E. Tulloss
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