The following is based on the description by Contu and Pacioni (1998).
The cap of A. cistetorum is 40 - 100 mm wide, lead gray at first, ash-gray in maturity, irregularly convex, then broadly convex, never umbonate, fleshy, slightly viscid when young, with a striate margin (up to 30% of the radius). Volval remnants are present as large warts or a single submembranous patch. The flesh is white and unchanging.
The gills are free, close to crowded, proportionately broad and thick, white, sometimes with a pink-ochraceous tint, often ash-gray with age.
The stem is up to 50 - 80 × 8 - 15 mm, cylindric or slightly narrowing upward, white to lead-gray, densely covered by a creamy powder. A ring is absent. The flesh is white, unchanging, and firm. The volva is submembranous, fragile, white with ochraceous shades evident even when young, and easily broken during collecting.
RET measured spores with the following results: (8.9-) 9.5 - 13.5 (-15.5) × (6.2-) 7.9 - 10.7 (-12.5) µm, subglobose to globose to broadly ellipsoid, and inamyloid. Clamps are absent at bases of basidia.
This species occurs in small groups in Mediterranean maquis habitat with these possible symbionts: Cistus (C. salviaefolius, C. monspelliensis) and oak (Quercus suber) occasionally present. This species was originally described from the island of Sardinia (Italy).
Dr. Contu was kind enough to send RET a number of color photographs and a collection of three fruiting bodies of A. cistetorum. From examining this material RET concludes that either there are a number of errors in the original description or the material RET was sent represents a different species. Assuming that the material RET received is A. cistetorum, then the cap colors are uniformly dark brown in some material and brown over the disc and brownish gray elsewhere in other material. The coloration difference does not seem correlated with age. The volval material does not contain only scattered inflated cells as is said in the original description. The inflated cells are unevenly distributed, but quite common, which correlates with the fragility of the volval limb. Without going into further detail on microscopy, the differences between RET's description and that of the original authors could be explained by such things their not measuring the spores in lateral view only, their making a section of the pileipellis that was not perpendicular to the surface of the cap, etc. Revision of the type and increasing familiarity with the range of variation of the cap color are important in order to fully understand this species.
Based on the material RET has examined, A. cistetorum is closest to the species group listed on the page for A. malleata (Piane ex Bon) Contu.—R. E. Tulloss and L. Possiel
11.xi.1997 M. Contu s.n. (orig. mat'l., RET 293-5)
L. V. Kudzma, Annandale, NJ
Contu. 1999b. Boll. Ass. Micol. Ecol. Romana 46: 19, pl. unnumbered.
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 will data from a revision of the
species (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 directly from the protolog of the present taxon is based upon
original research by R. E. Tulloss.
from protolog: 40 - 100 mm wide, lead-gray [a grayish brown] at first, then ash-gray, viscid at first; context white, unchanging; margin striate (up to 0.3R); universal veil as irregularly distributed warts or relatively large patch or patches, whitish, submembranous, fragile, with some ochraceous tint or spots [per image on this page]. [Note: Since the photograph on this page is Contu's, we have relied upon it to increase precision with regard to the color of the universal veil. The original text reads "ochraceous-whitish."—ed.]
from protolog: free, close to crowded, white sometimes with pinkish-ochraceous tint, often ash-grayish in age, proportionately rather broad and thick; lamellulae not described.
from protolog: 50 - 80 × 8 - 15 mm, short in proportion to pileus width, white to lead-gray, cylindric or slightly narrowing upward, entirely pruinose and with pruinose covering being source of pigmentation?; context white, unchanging; exannulate; universal veil as saccate volve, white with ochraceous tint evident even in young material, submembranous, fragile, "scarcely sheathing" and tending to remain [at least in part] in substrate during collection of basidiome, with white basal mycelium. [Note: With regard to pruinose covering of the stipe we have provided an interpretation of the original text which reads, "entirely covered by a colours pruinosity."—ed.]
from protolog: Odor and taste both week. Edible when cooked.
from protolog: suprapellis "with thick layer of ixocutis composed of hyphae 1.2 - 7.2 μm wide; subpellis comprising filamentous hyphae 2.4 - 9.6 μm wide, with vacuolar pigment. [Note: It appears that there may be some confusion here over the terminology used to describe this tissue.—ed.]
from protolog: On pileus: apparently not described. On stipe base, exterior surface: not described. On stipe base, interior: filamentous hyphae 2.4 - 12.0 μm wide, as loose open lattice; inflated cells 12 - 55 μm wide, colorless to brown; vascular hyphae 9.2 - 26 μm wide. On stipe base, inner surface: not described.
from protolog: not described.
RET: longitudinally acrophysalidic; filamentous, undifferentiated hyphae 2.7 - 9.6 μm wide, branching, dominating near surface; acrophysalides up to 233 × 36 μm, plentiful except at exterior stipe surface, apparently absent at exterior surface, dominant in interior; vascular hyphae 5.1 - 15.9 μm wide, sinuous, infrequent, most frequent at exterior surface.
lamella edge tissue
from protolog: inflated cells frequent, clavate to pyriform, 42 - 56 × 9.5 - 17 (-24) μm.
from protolog: [-/-/-] 10.0 - 13.2 × 7.0 - 13.2 μm, (Q = 1.0 - 1.4; Q' = 1.16), hyaline, inamyloid, globose (infrequently) to subglobose to broadly ellipsoid to ellipsoid, at least sometimes adaxially flattened (per figure); apiculus sublateral (per figure); contents monoguttulate (oil drop type); white in deposit. [Note: In this data, the Q value of the smallest recorded spore is the largest Q value and the Q value of the largest recorded spore is the smallest Q value. This is abnormal or at least unusual as is the sporograph which is quadrilateral rather than hexagonal. The latter suggests that the ranges of length, width, and Q are not based on the methods of this site.—ed.]
RET: [60/3/1] (8.9-) 9.5 - 13.5 (-15.5) × (6.2-) 7.9 - 10.7 (-12.5) μm, (L = 11.2 - 11.5 μm; L' = 11.3 μm; W = 9.0 - 9.2 μm; W' = 9.0 μm; Q = (1.09-) 1.12 - 1.44 (-1.56); Q = 1.26 - 1.27; Q' = 1.26), hyaline, colorless, smooth, thin-walled, inamyloid, subglobose to broadly ellipsoid to ellipsoid, adaxially flattened, sometimes expanded at one end; apiculus sublateral and cylindric to truncate-conic; contents dominately monoguttulate with additional small granules; white in deposit.
from protolog: In small groups in the Mediterranean maquis, very common in Sardinia. Associated with Quercus suber and Cistus monspieliensis L. or with C. monspieliensis alone.
RET: With C. monspieliensis.
Cistus monspeliensis is a shrub of the Mediterranean region (southern Europe and northern Africa). In recent years southern European authors have reported amanitas that are proposed as ectomycorrhizal with Cistus. At least two species of Cistus have been established to be mycorrhizal—C. incanus and C. albidus.
SARDINIA—Prov. Cagliari - Sette Fratelli,
1.xii.1981 G. Pacioni s.n. (paratype, AQUI).
Prov. Oristano - Marrubiu, Sant'Anna, 28.xi.1981 G.
Pacioni s.n. (paratype, AQUI). Prov. Sassari -
Luras, loc. Diga del Liscia, 26.xii.1995 M. Contu s.n.
SARDINIA—Prov. Sassari - Brandinchi,
11.xi.1997 M. Contu s.n. (original material, in
herb. Contu, authentic; RET 293-5, nrITS &
The material examined by RET is authentic, original material that is not cited in the protolog.
The authors do not mention graying of the universal veil; however, they do report brown inflated cells in its tissue. This is similar to the submembranous universal veil of A. submembranacea to which they compare the present species. They state without further comment that Contu's A. submembranacea var. griseoargentata ia a "grayish variant" of the present taxon. The following figure provides sporograph comparison of the present species with A. submembranacea:
If we set aside the sporograph based on the data from the protolog of the present species and use only data from RET's studies, then the sporographs have minimal overlap, and the proportionately rounder spores of A. submembranacea are easily distinguishable from the spores of the present taxon.
The same can be shown to be true for other taxa with distinctly graying, submembranous universal veil and subglobose to broadly ellipsoid spores, e.g., A. constricta, A. reidiana, A. sinicoflava, etc.
The authors expend some effort to distinguish the present taxon from three members of the group of European taxa in sect. Vaginatae with relatively narrow ellipsoid spores: A. argentea, A. huijsmanii, and A. mairei. The arguments rely on spore size and shape in large part; however, the difference in these characters is not always clear. Sporograph comparisons of the present species with these taxa are presented below:
On the other hand, they fail to mention A. oblongispora the spores of which are at least as similar to those of the present species as are those of the taxa they list and was originally described from Sardinia.
???more...give differentiation information for taxa where the difference is clear...examine universal veil of present taxon, etc.???
—R. E. Tulloss
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