The following description is based on Gilbert (1941) and RET's examination of the original collection.
The cap of Amanita irreperta is 44 mm wide, slightly sordid-cream,
becoming light buff, planar with a somewhat depressed
center, with a striate margin. The volva is present as easily
removed scales over the center.
The gills are white, free, subdistant. The short gills are truncate to rounded-truncate, scattered, unevenly distributed.
The stem is 42 × 6 mm, exannulate, white, subcylindric. The volva is saccate, membranous, with two pronounced limbs, 30 × 20 mm, with limbs thin at top.
The spores measure (Gilbert, 1941) 10 × 6 µm and are ellipsoid. RET's spore measurements from the original collection are as follows: (7.6-) 8.0 - 10.3 (11.2) × (4.7-) 4.8 - 6.4 (-6.8) µm and are ellipsoid to elongate, infrequently cylindric and amyloid.
Originally described from Madagascar singly from a forest in sandy soil.
This species is clearly a member of section Amidella based on my examination of the original collection.—R. E. Tulloss
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.
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.
RET has seen original material in PC (herb. Decary).
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 is based on Gilbert (1941) and on original research of R. E. Tulloss.
44 mm wide, slightly sordid cream-white, becoming Light Buff (1Y 8.5/4.5), planar with somewhat depressed disc, with sand over much of surface in original collection; context not described; margin striate (??R); universal veil as easily removed scales over disc.
free, subdistant?, white; lamellulae truncate to rounded-truncate, scattered, unevenly distributed.
42 × 6 mm, white, subcylindric; bulb lacking; context not described; exannulate; universal veil as saccate volva, membranous, with two pronounced limbs, ca. 30 × 20 mm, with limbs thin at top, with outer surface impregnated with sand in original collection.
Odorless. Taste not recorded.
filamentous, undifferentiated hyphae 3.4 - 8.7 µm wide, subradially arranged, partially gelatinized at surface, rather densely packed when viewed from above; vascular hyphae not observed.
filamentous, undifferentiated hyphae 1.5 - 9.5 µm wide, branching, plentiful, forming open lattice structure; acrophysalides common, ??-walled, subellipsoid (e.g., 60 × 38 µm) to clavate (e.g., 66 × 27 µm) to elongate-subfusiform (??); vascular hyphae 9.3± µm wide, yellow to golden yellow, sinuous, occasional.
collapsed and not rehydrating in original collection; bilateral.
collapsed and not rehydrating in original collection.
collapsed and not rehydrating in original collection.
On pileus, exterior surface: ??. On pileus, interior: ??. On pileus, lower surface: ??. On stipe base, exterior surface: ??. On stipe base, interior: filamentous, undifferentiated hyphae 1.9 - 6.8 µm wide, frequently branching, in fascicles and singly, interwoven without dominant orientation forming open lattice structure, occasionally with subrefractive yellowish walls and with yellowish-walled hyphae sometimes having slightly thickened walls; inflated cells probably dominating, but largely broken or with partially gelatinized walls, terminal singly(??), elongate-ellipspoid(??) to broadly clavate(??) to clavate, with fragments indicating sizes up to 93 × 35 µm or larger; vascular hyphae 3.0 - 14.9 µm wide, scattered to moderately common, often having frequent marked constrictions. On stipe base, inner surface: similar to interior, somewhat gelatinized.
longitudinally acrophysalidic; filamentous, undifferentiated hyphae 1.9 - 6.7 µm wide, branching, dominating near surface, plentiful in interior; acrophysalides dominant in interior, up to 156 × 32 µm or larger, apparently thin-walled; vascular hyphae 5.1?? - 7.4?? µm wide, occasional, difficult to distinguish from similar refractive hyphae of mold penetrating context.
[35/1/1] (7.6-) 8.0 - 10.3 (-11.2) × (4.7-) 4.8 - 6.4 (-6.8) µm, (L = 9.3 µm; L' = 9.3 µm; W = 5.6 µm; W' = 5.6 µm; Q = (1.43-) 1.45 - 1.81 (-2.19); Q = 1.66; Q' = 1.66), many in original collection collapsed, hyaline, colorless, thin-walled, smooth, amyloid, ellipsoid to elongate, occasionally cylindric, often adaxially flattened; apiculus sublateral, proportionately small, cylindric; contents granular to mono- or multiguttulate; color in deposit not recorded.
Solitary. In forest, on sandy soil.
MADAGASCAR, REPUBLIC OF: ANTSERANANA? or MAHAJANGA? Maromandia, 25?.ii.1923 Raymond DeCary s.n. (PC).
This provisionally named taxon should be easily recognizable if found again because of the combination of small size, a striate margin, a membranous volval sac, an exannulate stipe, and ellipsoid to elongate amyloid spores.
Gilbert (1941) placed A. irreperta in Amanita section Amidella. The striate margin, apparently truncate lamellulae, exannulate stipe, and form of fragments of universal veil on the pileus support this placement. Unfortunately, the anatomy of the universal veil could not be ascertained with sufficient detail to add further support.
—R. E. Tulloss
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