The cap is approximately 70 mm wide, has a central umbo, and is striate for about half
of its radius.
The gills are free, crowded, and white. The short gills are truncate.
The stem is approximately 150 x 15 mm, with brownish gray fibrils that may become more yellowish
from handling. The volval sac becomes gray from the top down (starting when expansion of the fruiting body) begins
and quickly becomes fragile and cracked.
The spores measure (9.8-) 10.4 - 14.0 (-15.4) × (8.2-) 9.0 - 11.5 (-12.8) µm and are subglobose to broadly ellipsoid (occasionally globose or ellipsoid) and are inamyloid. Clamps are absent from bases of basidia.
The present species occurs at least with birch and conifers.
The species is known with confidence from Scotland, England, and Norway and undoubtedly is more widely spread in northern Europe. Reid's material was collected in a calcareous region.—R. E. Tulloss
Tulloss in Tulloss et al.
Amanitaceae 1(2): 4.
"Chestnut and Gray Amanita"
≡Amanita castaneogrisea Contu nom. inval.1998. Micol. Veg. Medit. 12(2): 146.
[Lacking full and direct reference to name being replaced. ICBN §33.2]
≡Amanita submembranacea var. bispora D. A. Reid. 1987. Notes Roy. Bot. Gard. Edinburgh 44(3): 514.
=Amanita submembranacea sensu D. A. Reid. 1987. Notes Roy. Bot. Gard. Edinburgh 44(3): 513.
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.
castaneus "chestnut brown" + griseus "gray"; hence, (to make the most sense of the name) "chestnut and gray"
Tulloss. 2000a. Boll. Gruppo Micol. G. Bresadola 43(2): fig. 9.
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 core of the macroscopic description comes from the protolog (Reid 1987), Reid's conception of A. submembranacea (Ibid.), a type study (Tulloss 1994), and fresh material collected in Scotland. The microscopic detail derives from original research of R. E. Tulloss.
Tulloss (1994): 70 mm wide, Vandyke brown, paler toward margin, shallowly convex with central umbo; context not described; margin plicate, nonappendiculate; universal veil absent.
submembranacea sensu Reid:
Tulloss (1994): pinkish; lamellulae not described [apparently few in var. submembranacea sensu Reid (1987: 513)]
submembranacea sensu Reid:
Tulloss (1994): 150 × 15 mm, pallid ground, decorated with gray zig-zag scales; context not described; exannulate; universal veil saccate, submembranous, cracking and breaking into patches, gray inside and out except white on exterior at very base of stipe.
Tulloss (1994): 25 - 80 µm thick, orange-brown; filamentous, undifferentiated hyphae 1.0 - 7.7 µm wide, with hyphae of smaller diameters concentrated near surface, branching, subradially arranged, tightly interwoven, partially gelatinized, often containing yellow-brown to orange-brown intracellular pigment (in flocculent clumps in 3% KOH); vascular hyphae 1.0 - 7.8 µm wide, branching, common, locally densely tangled.
Tulloss (1994): filamentous, undifferentiated hyphae 1.3 - 5.6 µm wide, in fascicles, plentiful; acrophysalides elongate to broadly clavate to ellipsoid, narrowest near pileipellis, thin-walled, plentiful to dominant, up to 94 × 44 µm; vascular hyphae 7.8 - 8.4 µm wide, infrequent.
Tulloss (1994): bilateral, but obscurely so (see curved bases of basidia); wcs = 40 - 55 µm (moderately good reinflation); filamentous, undifferentiated hyphae 2.0 - 5.0 µm wide, densely interwoven, obscuring inflated cells if any are present, coiled and twisting, branching, occasionally with yellowish walls; inflated cells not observed; vascular hyphae 1.7 - 3.0 µm wide, sinuous or corkscrew-like. Note: curved bases of basidia indicates imperfect rehydration.
Tulloss (1994): poor rehydration. [Reid (1987: 535, fig. 9d) provides an excellent illustration in the protolog.]
Tulloss (1994): 26 - 44 × 7.8 - 14.7 µm, sometimes curved to one side at base, thin-walled, with 50% 4-sterigmate, 40% 2-sterigmate, remainder 1- and 3-sterigmate; no clamps observed. Note: Poor rehydration may have resulted in the basidia being reported as shorter than they were in fact.
Tulloss (1994): On pileus: absent except for scattering of gelatinized fragments of inflated cells and hyphae. At stipe base, exterior surface: filamentous, undifferentiated hyphae 2.1 - 7.7 µm wide, branching, in fascicles that are very well separated and lack any dominant orientation, partially gelatinized, some with exterior incrustation, often with yellow deposits on interior of cell walls, occasionally with yellowish walls; vascular hyphae 2.1 - 9.8 µm wide, common, locally plentiful in tangles and knots, occasionally branching. At stipe base, interior: filamentous, undifferentiated hyphae 0.8 - 9.1 µm wide, often in fascicles, loosely interwoven, branching, thin-walled or (especially those of larger diameter) with walls slightly thickened (up to 0.5 µm thick), often with longitudinal orientation, occasionally with yellowish walls; inflated cells globose to subglobose (up to 55 × 49 µm) or ellipsoid to broadly clavate to clavate (up to 55 × 40 µm), sometimes elongate (e.g., 56 × 13.3 µm) and then occasionally being slightly curved, terminal, thin-walled, sometimes with yellow-brown intracellular pigment, often colorless; vascular hyphae 1.6 - 7.7 µm wide, branching, locally in small knots or tangles. [Reid (1987: 535, fig. 9a) provides an excellent illustration in the protolog.] At stipe base, inner surface: similar to interior.
Tulloss (1994): longitudinally acrophysalidic; filamentous, undifferentiated hyphae 1.5 - 9.8 µm wide, in fascicles, often with yellow deposit on interior cell walls or with yellowish walls; acrophysalides up to 170 × 32 µm, occasionally with yellowish walls; vascular hyphae 4.9 - 9.1 µm wide, with irregular outline, yellowish with brown tint, uncommon.
Tulloss (1994): [40/1/1] (9.8-) 10.9 - 13.2 (-15.4) × (9.0-) 9.1 - 11.2 µm, (L = 11.5 µm; W = 10.5 µm; Q = 1.01 - 1.23 (-1.34); Q = 1.10), hyaline, colorless, smooth, thin-walled, inamyloid, globose to subglobose to broadly ellipsoid, infrequently ellipsoid, usually at least somewhat adaxially flattened, occasionally expanded at one end; apiculus sublateral, cylindric, prominent; contents granular or monoguttulate with or without small granules; white in deposit.
composite of all material revised by RET: [51/2/2] (9.8-) 10.4 - 14.0 (-15.4) × (8.2-) 9.0 - 11.5 (-12.8) μm, (L = 11.5 - 12.2 μm; L' = 11.6 μm; W = 10.0 - 10.5 μm; W' = 10.4 μm; Q = (1.01-) 1.02 - 1.33 (1.46); Q = 1.10 - 1.22; Q' = 1.13).
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.