| name |
Amanita ameghinoi |
| author |
(Speg.) Singer. 1952. Sydowia 6: 344. |
| name status |
nomen acceptum |
| english name |
"Ameghino Lepidella" |
| synonyms |
≡ Armillaria ameghinoi Speg. 1899. Anales Mus. Nac. Hist. Nat. Buenos Aires 6: 97.
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.
|
| etymology |
genitive of Latinized name; hence, "Ameghino's" or "of Ameghino" |
| MycoBank nos. |
292438, 147688 |
| GenBank nos. |
Due to delays in data processing at GenBank, some accession numbers may lead to unreleased (pending) pages.
These pages will eventually be made live, so try again later.
|
| holotypes |
LPS |
| type studies |
Bas. 1969. Persoonia 5: 357, figs. 42-44. |
| revisions |
Tulloss, here |
| selected illustrations |
Spegazzini. 1925. Bol. Acad. Nac. Ci. 28: 277.
Spegazzini. 1926. Rev. Argent. Bot. 1: 232. |
| intro |
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
material.
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 not cited as originating in (Bas 1969) is based upon original research by R. E. Tulloss. |
| pileus |
50 - 100 mm wide, white to pale pinkish orange, convex to planar, “probably dry” (Bas 1969: 358), smooth and unbroken at first, then breaking up into coarse subpyramidal warts with radially fibrillose sides in exsiccata; context fleshy, relatively thick; margin nonsulcate, appendiculate, inflexed; universal veil as a dense covering of small to large scales, whitish at first, then dingy brown. |
| lamellae |
adnexed to free, sometimes with lines on apex of stipe, rather crowded, white to pallid, sometimes greenish (Singer 1952: 344), with entire edge; lamellulae subtruncate??. |
| stipe |
50 - 90 × 10 - 15 mm, white to pallid orange, subcylindric, somewhat pulverulent above partial veil, more or less coarsely scaly below; slim basal bulb sometimes present, sometimes only a slight inflation of stipe; context white, unchanging when cut or bruised, sublactescent, stuffed to solid; partial veil persistent, pendent, white, membranous, skirt-like, superior, with thickened margin; universal veil as scales on stipe, color as on pileus. |
| odor/taste |
Odor weakly fungoid. Taste at first mild, then acrid in throat. |
macrochemical
tests |
No spot tests recorded. POISONOUS. In a case in which basidiocarps were thoroughly cooked, causing nausea, dizziness, vomiting, and heart palpitations lasting about 24 h (Spegazzini 1926: 231). In a case in which a single basidiocarp was partially cooked by roasting, causing nausea, bilious and copious vomiting, sharp stomach pains, much diarrhea, migraine, fever, and fainting fits, with the majority of the most serious symptoms passing within 48 h (Spegazzini 1926: 233). |
| pileipellis |
lacking over much of surface, ungelatinized pileus context exposed (colored orange-brown and slightly gelatinized locally); where dense surface layer of filamentous, undifferentiated hyphae present, then not clearly distinguished from pileus context. |
| pileus context |
quite dense (dominated by filamentous, undifferentiated hyphae) near surface, progressively less dense below until dominated by acrophysalides; filamentous, undifferentiated hyphae 1.5 - 6.5 µm wide, interwoven, branching, often in fascicles (especially toward surface), sometimes with slightly thickened walls; acrophysalides subglobose to subpyriform to broadly clavate (up to 67 × 46 µm), clavate to narrowly clavate to elongate-fusiform (up to 110 × 43 µm), walls thin to somewhat thickened(?); vascular hyphae 1.8 - 8.5 µm wide, branching, common near surface, very uncommon below surface, locally tangled or knotted. |
| lamella trama |
bilateral, 90 - 120 µm wide, with hyphae diverging from central stratum at angles ranging from very shallow to nearly 60°; having a very distinct central stratum without inflated cells (wcs = 15 - 20 µm); filamentous, undifferentiated hyphae 2.2 - 12.0 µm wide, with narrowest in central stratum (these thin-walled) and widest forming diverging elements (these with walls up to 1.0 µm thick) and sweeping in smooth curve from central stratum until perpendicular to it or nearly so, typically reaching subhymenium via one or two segments with total length of about 70 µm, occasionally bifurcating into stubby branches just below subhymenium, typical sizes of paired segments 49 × 12.0 µm and 22 × 10.5 µm with smaller segment giving rise to elements of subhymenium; divergent, terminal inflated cells absent; vascular hyphae not observed; clamps present. |
| subhymenium |
wst-near = 65 - 75 µm; wst-far = 110± µm; with basidia arising from short (occasionally branching) hyphal segments or small inflated cells, the elements in a shallow (1 to 3 cells deep) moderately branching arrangement, with some regions appearing cellular, other regions with elements largely uninflated. |
| basidia |
32 - 53 × 9.2 - 14.0 µm, often broadest at point at which projection beyond surrounding basidioles begins, thin walled or with wall up to about 0.5 µm thick, dominantly (20 of 35 basidia checked) 2-sterigmate, also 4-, 1-, and 3-sterigmate; sterigmata up to 12.5 × 3.5 µm; clamps plentiful and often rather large. |
| universal veil |
On pileus: nearly completely absent, with what remains orange-brown, gelatinizing, dominated by filamentous, undifferentiated hyphae, with few elongate cells inflated to a diameter much bigger than that of the hyphae and these broken, collapsed; all structures seen with periclinal orientation [per (Bas 1969: 357 [fig. 44], 360) “chains of elongate cells 60 - 100 × 20 - 40 µm (perhaps also larger) on hyphae 3 - 7 µm wide; many of these chains of cells parallel in crushed mounts but exact position on cap uncertain”]. In scales on stipe: extensively gelatinized, orange-brown, elements parallel, but structure difficult to determine; vascular hyphae up to 10.5 µm wide. |
| stipe context |
longitudinally acrophysalidic; filamentous, undifferentiated hyphae 3.2 - 12.5 µm, plentiful to locally dominant, branching, with walls slightly thickened (up to 0.5 µm thick), branching; acrophysalides plentiful to locally dominant, thin-walled, up to 120 × 50 µm; vascular hyphae absent or very scarce; clamps observed. |
| partial veil |
filamentous, undifferentiated hyphae 3.8 - 10.0 µm, branching, interwoven, at least partially gelatinized, dominating; inflated cells occasional, gelatinized, on surfaces, e.g., 67 × 61 µm, cannot be distinguished in gelatinized interior; vascular hyphae not observed; fragment of limbus internus on underside as small number of short chains of elongate cells (under 50 µm long), gelatinized. |
| basidiospores |
from type study of Bas (1969): [10/1/1] 11.0 - 13.0 (-13.5) × 8.0 - 10.0 μm, (Q = 1.30 - 1.35; Q = 1.30).
composite of data from all material revised by RET: [40/2/1] (10.0-) 10.2 - 12.8 (-14.8) × (7.8-) 8.0 - 10.0 (-12.0) μm, (L = 11.6 μm; L' = 11.6 μm; W = 9.0 - 9.1 μm; W' = 9.1 μm; Q = (1.12-) 1.18 - 1.44 (-1.56); Q = 1.26 - 1.30; Q' = 1.28), hyaline, colorless, smooth, with walls up to 0.5 μm thick, amyloid, subglobose to broadly ellipsoid to ellipsoid, sometimes expanded at one end, frequently at least somewhat adaxially flattened; apiculus sublateral, cylindric, proportionately rather small; contents refractive and uniform to granular to mono- or multiguttulate; white (at first) in deposit. |
| ecology |
"Bosquecillo." In the pampas in the area of La Plata. In a small woods in Buenos Aires, subgregarious. |
| material examined |
Bas (1969): ARGENTINA: BUENOS AIRES—La Plata, 20.iii.1888 C. Ameghino s.n. (holotype, in herb. Spegazzini 2859 => LPS).
RET: ARGENTINA: BUENOS AIRES—Buenos Aires, km. 100, Ruta #2, 16.ii.1963 Jorge E. Wright s.n. (BAFC 30.888 as "Agaricus").
URUGUAY: DPTO. CERRO LARGO—Palleros, 9-16.iii.1935 W. G. Herter 95552 [Pl. Uruguayensis Exsicc. no. 1764] (BPI 751128). |
| discussion |
Bas (1969): "The type, the only collection studied, is in very poor condition and stems are lacking. It was impossible to analyze the structure of the trama of the gills. Singer (1952) found it bilateral in this psecies, but did not mention the collection by which he verified this character. Singer also found the basidia 4-spored. But in the type the basidia are mostly 2-spored and sometimes 1- or 3-spored (about 30 completely re-inflated basidia observed). If a 4-spored form exists, its spores are probably somewhat smaller than those of the type. This species is poisonous (Spegazzini, 1926: 231).
"Spegazzini described the flesh as being sublactescent. This noteworthy feature was not mentioned by Singer, who collected the species himself.
"Spegazzini (1925: 276) considered Amanita bresadolae (Rick) Rick to be a synonym of his Armillaria ameghinoi, Singer (1953: 64) who studied the type, found Rick's species to be a Lepiota and renamed it L. crassior Singer.
"See discusssion under A. salmonea." [Note: This can be found on this site in the "discussion" data field of the technical tab for A. subcaligata.—ed.]
RET/CRC: The holotype was not available to us from BAFC; however, a specimen from Buenos Aires was available from which we were able to obtain additional data.
The Uruguayan collection from BPI was apparently originally sectioned and dried in a plant press and is presently in poor condition and quite moldy. We were able to identify the species with some confidence, but not able to find more than three spores on the basidiome; hence, data from these spores has not been included above. |
| citations |
—R. E. Tulloss, C. Rodríguez Caycedo |
| editors |
RET |
|
Spore data sets and their composite