The cap of Amanita masasiensis is 30 - 70 mm wide, convex, becoming planar and (sometimes) depressed in the center, lacking an umbo or with a low broad one, smooth, slightly sticky, nonappendiculate, with a striate margin (35 - 40% of the radius). The cap is yellow to yellow-orange, more strongly pigmented and redder in the center, and yellow at the margin. The flesh is white, strongly yellow under the cap's skin, and sometimes somewhat yellow above the gills; it is soft to firm. The volva is occasionally present as white patches.
The gills are free, fairly crowded, yellow, thin, with a smooth and concolorous edge.
The stem is 60 - 70 × 9 - 11 mm, yellow, and cylindric. The flesh is white, brittle-fibrous, stuffed, and becoming hollow. The rather large, saccate volva is membranous, white, somewhat floccose on exterior surface,and attached at the extreme base of the stem.
The spores of this species measure (8.5-) 8.6 - 10.8 (-12.1) × (5.5-) 6.0 - 7.0 (-9.0) µm and are ellipsoid to elongate and inamyloid. The original description describes spores as too broad because of an apparent typographical error. Clamps are common at bases of basidia.
Amanita masasiensis was originally described from Tanzania. It is also known from Zambia. It occurs in miombo woodland with Brachystegia and Uapaca. It has also been found in a plantation of Arandarium. It can be assigned to Amanita stirps Hemibapha. Its cap pigmentation is similar to that of A. hemibapha (Berk. & Broome) Sacc. The latter has smaller spores, different associated woody plants, and is known from southern India and Sri Lanka.
The present species is a market species in Africa. For other regional market species of sect. Caesareae, see A. mafingensis Härk. & Saarim..—R. E. Tulloss
S. Sanchez et al., (direct deposit), Roy. Ontario Mus., Toronto
H; isotype, DSM
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).
Paragraphs of black text will be labeled if further subdivision of
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 of the present species and original research of RET.
from protolog: 30 - 70 mm wide, yellow-orange, darker and redder over disc, convex at first, becoming planar, smooth, slightly sticky; context white except strongly yellowish under pileipellis and somewhat yellowish above lamellae, soft to firm; margin striate for 6 - 13 mm [est. 0.35 - 0.4R]; universal veil infrequently as few white membranous patches.
RET: up to 76 mm wide in Zambian material, usually not umbonate at first, sometimes with low broad umbo.
from protolog: free, fairly crowded, yellow, 4 - 6 mm broad, with edge smooth and concolorous.
from protolog: 60 - 70 × 9 - 11 mm, yellow, cylindric, with surface more or less "fluff"; context stuffed, becoming hollow, white except yellow below surface, "brittle-fibrous"; partial veil superior, pendent, menbranous (per figure), orange-yellow, tihn, slightly striate, in specimen 1398 white above and yellow below; universal veil as saccate volva, attached only to very base of stipe, white "high and broad" [enclosing 30 - 45% of stipe and with height ca. 1.4 - 1.5× width after eruption of pileus and prior to collapse of sac (per figure)], with exterior somewhat floccose, with distinct limbus internus.
from protolog: of irregularly subglobose to angular inflated cells 5 - 20 μm wide.
from type study of RET: pseudoparenchymatous (cellular); with 2 - 3 layers of inflated cells below bases of longest basidia.
from protolog: 35 - 50 × 8 - 15 μm, 4-sterigmate; clamps not described.
from protolog: On pileus: absent. On stipe—"floccose" material of limbus internus: filamentous hyphae "loose"; inflated cells up to 50 - 70 μm wide. On stipe base, external surface layer: filamentous hyphae interwoven; inflated cells occasional; vascular hyphae occasional. On stipe base, interior: strongly gelatinized.
from protolog: longitudinally acrophysalidic; [?]"partially gelatinized."
from protolog: sterile; filamentous hyphae in loosely interwoven cable-like structure (per figure); inflated cells 25 - 55 μm long, "cystidia-like," clavate to broadly clavate and terminal singly (both per figure)
from protolog: [-/-/-] 8.5 - 12 × 6 - 9 µm, (L’ = 10.0 µm; W’ = 6.3 µm; Q = 1.20 - 1.50; Q’ = 1.36), hyaline, smooth, inamyloid, ellipsoid to elongate; apiculus sublateral (per figure); contents as "one big guttule"; white in deposit. [Note: The sporograph for this data is greatly extended in length and width, possibly because the ranges provided in the protolog are not of a form compatible with the standard on this site. The reader may wish to use the ?User+sporograph page to manually delete the protolog data when comparing spores of this species with other taxa.—ed.]
from type study of RET: [40/1/1] (8.5-) 9.0 - 10.7 (-11.5) × (5.5-) 6.0 - 6.8 (-7.1) μm, (L = 9.8 μm; W = 6.4 μm; Q = (1.32-) 1.40 - 1.67 (-1.87); Q = 1.53), hyaline, colorless, thin-walled, smooth, inamyloid, ellipsoid to elongate, at least somewhat adaxially flattened; apiculus sublateral, cylindric; contents monoguttulate; white in deposit.
composite of all material revised by RET: [60/2/2] (8.5-) 8.6 - 10.8 (-12.1) × (5.5-) 6.0 - 7.0 (-9.0) µm, (L = 9.6 - 9.8 µm; L’ = 9.7 µm; W = 6.4 - 6.6 µm; W’ = 6.4 µm; Q = (1.32-) 1.38 - 1.64 (-1.87); Q = 1.47 - 1.53; Q’ = 1.51).
from protolog: At 300 - 1000 m elev. On brown soil of Brachystegia-Uapaca woodland or in miombo woodland dominated by Uapaca and Faurea with some Parinari or in degraded miombo woodland with Brachystegia, Julbernardia, Uapaca, Syzygium, and Combretum or in field under Anacardium. "...probably mycorrhizal with several indigenous trees, Uapaca and Brachystegia being most often present. Once found in a plantation of Anacardium."
from protolog: TANZANIA: SOUTHERN PROV.—Masasi Distr. - Kigweje Village, ca. 60 km SW of Masasi. [10 38 CD, 300 m], 24.i.1993 Tiina Saarimäki et al. 1376 (holotype, H 7002977). Songea Distr. - ca. Namtumbo, Lilunde Village [10 36 AC, 700m]. 26.i.1993 T. Saarmäki et al. 1398 (nonconformant paratype, H); Hanga, Nyamagoma Village, 40 km N of Songea [10 35 BC, 900 m], 27.i.1993 T. Saarimäki 1433 (paratype, H); Matomondo, 29 km from Songea toward Mbinga [10 35 CB, 800 m], 29.i.1993 T. Saarimäki 1444 (paratype, H 7002979). [Note: Six-character location codes given above are those of Polhill (1988) and Leistner and Morris (1976) per Härkönen et al. (1994).]
from type study of RET: TANZANIA: SOUTHERN PROV.—Masasi Distr. - Kigweje Village, ca. 60 km SW of Masasi. "locality T8" [10 38 CD, 300 m], 24.i.1993 Tiina Saarimaki et al. 1376 (holotype, H 7002977).
RET: ZAMBIA: COPPER BELT PROV.—Unkn. Distr. - along hwy. btwn. Kitwe and Chingola, 14-24.xii.2000 David Arora 00-318 (RET 344-5; SFSU).
In the "basidiospores" data field, above, there is a striking difference between the sporograph from the protolog and that from RET's examination of material from the holotype. Since the protolog spore data is not written in the form used on this site, it seems probable that extremes were not differentiated by the authors of the protolog; hence, the sporograph is extended both with regard to length and width. It is also notable that both the upper and lower limits of the range of Q from the protolog are depressed compared to RET's data. A probable cause of this is measurement of spores in multiple, non-lateral orientations, which increases most spores' width measurements and, consequently, decreases the values obtained for Q.
One of the paratypes of A. masasiensis was noted to have had a differently pigmented partial veil in the protolog: "in specimen 1398 upper surface white, underneath yellow." This raises some concern over whether this material is conspecific with the holotype.
—R. E. Tulloss and L. P. Tang
Information to support the viewer in reading the content of "technical" tabs
can be found here.
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.