The cap of Amanita preisii is 50 - 80 mm wide, convex to plano-convex,
finally slightly depressed at the center, white to cream
with a pale ochraceous tinge at the center, viscid when
moist, with a nonsulcate, appendiculate margin. The cap
is scattered with very thin, hardly discernible patches or flakes belonging to volva.
The gills are moderately crowded, adnexed to narrowly adnate, moderately broad,
and white to cream. The short gills are truncate to obliquely truncate.
The stem is 80 - 120 × 8 -
20 mm, subcylindrical, farinaceous, white, sometimes with
rusty spots, with the volva usually leaving a fragile,
membranous limb on the top of the bulb.
The spores measure (9.5-) 10 - 12 (-12.5) × 5.5 - 6 µm and are amyloid and
elongate to cylindrical. Clamps are absent at bases of basidia.
This species was
originally described from southwestern Australia. Dr. Bas
(1969) reviewed material of J. Gentilli that appeared to
conform well with what was known of Fries' species.
The collections examined
by Bas were collected "under shrubs and Eucalyptus
in West Australia." Gentilli reported the species to
be common in that state.
non Amanita preissii sensu Voglino. 1893. Boll. Soc. Bot. Ital. "1893": 468. [?=A. verna sec Gilbert (??not noted in 1918 or 1941??)]
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.
genitive of Latinized name, "Preiss'" or "of Preiss"
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 text below is derived from the revision of Bas (1969).
Bas (1969): 50 - 80 mm wide, white to cream with pale ochraceous tinges, convex to plano-convex, finally slightly depressed over disc; context not described; margin non-sulcate, appendiculate; universal veil as scattered barely discernible patches or flakes, very thin.
Bas (1969): adnexed to narrowly adnate, moderately crowded, white to creamy, becoming ventricose, moderately broad, with flocculose edge when young; lamellulae truncate to obliquely truncate(?), few seen.
Bas (1969): 80 - 120 × 8 - 20 mm, white, sometimes with rusty spots, subcylindric, farinaceous, bulb napiform, 30 - 50 × 20 - 45; context not described; partial veil apical, membranous to friable, faintly striate: universal veil usually as limbate volva on top of bulb, with limb 2 - 10 mm high.
Bas (1969): distinctly gelatinized; filamentous hyphae 3 - 8 μm wide, interwoven, hardly coloring in alkaline solution.
Bas (1969): bilateral; with scattered vascular hyphae.
Bas (1969): On pileus: filamentous hyphae 5 - 15 μm wide, abundant; inflated cells rather abundant, globose to ellipsoid to broadly clavate (up to 70 & 60 μm and 100 × 50 μm, probably mainly terminal singly) and elongate (up to 120 × 30 μm, scattered); clamps lacking. On stipe: comprising elements similar to those on pileus, but tissue denser; filamentous hyphae with strong tendency to longitudinal orientation.
Bas (1969): [20/2/2] (9.5-) 10.0 - 12.0 (-12.5) × 5.5 - 6.0 μm, (Q = 1.70 - 2.20; Q = 1.90 - 2.0), colorless, hyaline, thin-walled, amyloid, elongate to cylindrical, often adaxially depressed, sometimes substrangulate; apiculus not described; contents slightly refractive; white in deposit.
Bas (1969): Terrestrial under shrubs and Eucalyptus.
AUSTRALIA: WESTERN AUSTRALIA—City of Perth - King's Pk., vi.1953 J. Gentilli s.n. (L), vii.1953 J. Gentilli s.n. (L).
Bas (1969): "The caps of both specimens studied are covered with sand. Here and there, however, underneath the grains of sand, minute flakes can be found, which are apparently remnants of the volva. But also on the parts of the cap, which macroscopically seem to be glabrous, scattered broad hyphae and inflated cells occur. Apparently the part of the volva near the attachment to the bulb is submembranous, but the part over the cap friable.
"The species has been reported to be poisonous (Cleland 1943).
"The type material of A. preissii seems to have been lost. It was collected by Preiss in May 1839 in southwest Australia (Preiss 2665).
"Fries' concise description fits the present species fairly well. According to Gentilli (1953), it is not uncommon in Western Australia, and his interpretation presents no difficulties.
"Because of the slight limb on top of the not or hardly marginate bulb, the absence of clamp, and the elongate to cylindrical spores, A. preissii resembles A. roanokensis and A. alliacea; these differ mainly in having even slenderer, frequently bacilliform spores."
—R. E. Tulloss
Information to support the viewer in reading the content of "technical" tabs
can be found here.
1. Amanita preisii, Western Australia, Australia.
Dr. C. Bas - (1) Western Australia, Australia, reproduced by courtesy of Persoonia, Leiden, the Netherlands,
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.