| name | Amanita islandica |
| name status | nomen acceptum |
| author | Melot |
| english name | "Iceland Ringless Amanita" |
| images |
  1. Amanita islandica, Norway.  2. Amanita islandica, Norway.  3. Amanita islandica, Sweden.  4. Amanita islandica, Sweden. |
| cap |
The cap of A. islandica is 100 - 130 mm wide, moist, subovoid, then convex, broadly umbonate, with a dense, nonappendiculate, sulcate margin. The cap is white at first, but conspicuously graying with age, pale tan in exsiccatum. The flesh is white, proportionately very thick in disc, thin at margin, soon soft. The volva is absent. |
| gills |
The gills are very crowded, white then creamy white, thin with the edge minutely flocculose and remaining white in some dried material. The short gills are subtruncate to subattenuate, of diverse lengths, unevenly distributed, and common. |
| stem |
The stem is up to 170 × 15 (-25) mm, robust and proportionately quite long, white, sometimes browning on the lower portion. Near the top of the stem, young specimens have a rather thick flocculent covering (sheath easily seen in the illustrations of Norwegian material). The flesh is white with cottony-fibrillose stuffing. The saccate volva is thick, white on exterior surface, with pale orange tint on the inner surface, saccate or remaining as a single large, membranous patch several millimeters from the base of the stem. |
| spores |
The spores measure (8.8-) 9.3 - 13.2 (-15.0) × (8.0-) 8.4 - 11.5 (-14.5) µm and are inamyloid and subglobose to broadly ellipsoid (infrequently globose, infrequently ellipsoid). Spores on immature gills are often toward the smaller end of the size distribution and tend to be more nearly globose. Clamps are absent from the bases of basidia. |
| discussion |
A species that is similar to the present one is A. arctica Bas, Knudsen & Borgen. This latter species is a shorter-stemmed, but robust taxon with a smaller and less robust volva that may be cupulate or absent, and it has infrequent clamps on the bases of basidia. Both taxa have floccose material near the apex of the young stem and brownish staining of the cap in older specimens. Amanita islandica should also be compared to A. vaginata var. alba Gillet—a more fragile species with longer marginal striations on the cap. Amanita islandica was originally described from Iceland. Known associated trees are Birch and Spruce. A number of collections have been made recently in Norway and Sweden.—R. E. Tulloss |
| brief editors | RET |
| name | Amanita islandica | ||||||||
| author | Melot. 1992. Doc. Mycol. 22(85): 20. | ||||||||
| name status | nomen acceptum | ||||||||
| english name | "Iceland Ringless Amanita" | ||||||||
| etymology | Latin adjectival form of "Iceland" | ||||||||
| MycoBank nos. | 355466 | ||||||||
| GenBank nos. |
Due to delays in data processing at GenBank, some accession numbers may lead to unreleased (pending) pages.
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| ||||||||
| holotypes | in herb. J. Melot | ||||||||
| type studies | Tulloss, here | ||||||||
| intro |
The following text may make multiple use of each data field. The field may contain magenta text representing a type study by Tulloss. The same field may also contain black text, which will represent a revision of the species by Tulloss. 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 or other place in the text where data is missing; for example, a place name or a measurement. The following is based upon original research by R. E. Tulloss. | ||||||||
| pileus |
protolog & RET type study of A. islandica: 100 - 130 mm wide, white at first, but conspicuously graying, pale tan in exsiccatum, moist, subovoid, then convex, broadly umbonate; context white, proportionately very thick in disc, thin at margin, soon soft; margin densely (but short—about 0.15R in exsiccatum) sulcate, nonappendiculate; universal veil absent. Tulloss 8-19-99-B: 136 mm wide, white, becoming sordid or brownish after refrigeration, brown on the edge of wounds, broadly campanulate, lacking distinct umbo, subshiny, waxy; context white, with brown spots in old wounds, 12 mm thick over stipe, thinning evenly to margin; margin striate (0.15R), not appendiculate; universal veil as large membranous smooth white patches, detersile, graying and darkening on some edges after refrigeration. | ||||||||
| lamellae |
protolog & RET type study of A. islandica: very crowded, white, then creamy white, thin, [up to 15 mm broad,] with edge minutely flocculose and remaining white in exsiccatum; lamellulae subtruncate to subattenuate, of diverse lengths, unevenly distributed, common. Tulloss 8-19-99-B: free, without decurrent line on stipe apex, pale yellow-orange-cream in mass, cream in side view, with no apparent bruising or staining, 8.5 mm broad; lamellulae truncate, unevenly distributed, of diverse lengths, plentiful. | ||||||||
| stipe |
protolog & RET type study of A. islandica: up to 170 × 15 (-25) mm, robust and proportionately quite long, white, browning in lower portion; context white, with cottony-fibrillose stuffing; partial veil as copiously floccose-pulverulent region near apex (covering most of upper 40 mm of stipe in exsiccatum), white; universal veil as saccate volva, thick, white on exterior surface, with pale orangish tint on inner surface, remaining only as single large membranous patch several mm from base of stipe in portion of exsiccatum reviewed. Tulloss 8-19-99-B: 207 × 19 mm, white, with surface fibrils graying after refrigeration, narrowing upward, flaring slightly at apex, longitudinally striatulae, with flocculent, uneven (but continuous) bands encircling stipe at bottom of flocculent sheath (with sheath descending 50 mm from stipe apex) and near stipe base (limbus internus?); context off-white, not bruising or staining except for ochraceous tint at very base, stuffed with dense white fibrillose material with fibers having longitudinal orientation, with central cylinder 9.5 mm wide, with larval tunnels concolorous; universal veil as saccate volva, smooth, slightly leathery (partially dried), white with pale yellow-brown tint and staining, 34 × 29 (most left on pileus), with limb clearly divided from stipe base by line, with stipe and inner volval surface bound rather firmly by hyphae; limbus internus not visible. | ||||||||
| odor/taste |
protolog & RET type study of A. islandica: not recorded. not recorded due to age of specimen. | ||||||||
| macrochemical tests |
protolog & RET type study of A. islandica: none recorded. none recorded. | ||||||||
| pileipellis | protolog & RET type study of A. islandica: (130-) 155 - 175 µm thick, gelatinized only at surface, otherwise partially gelatinized or ungelatinized, colorless or slightly yellowish; filamentous, undifferentiated hyphae 2.2 - 8.0 µm wide, branching, densely packed, dominantly subradially arranged; vascular hyphae 2.0 - 17.5 µm wide, common, branching, most easily seen in scalp section, sinuous, occasionally coiled or loosely tangled, with relatively common abrupt constrictions, yellow to brownish yellow in 3% KOH. | ||||||||
| pileus context | protolog & RET type study of A. islandica: filamentous, undifferentiated hyphae 2.5 - 9.0 µm wide, branching, common, often in fascicles, occasionally anastomosing, with walls thin or (rather commonly) up to 0.8 µm thick, with intercalary partially inflated segments up to 21.0 µm wide; acrophysalides plentiful, broadly fusiform to clavate (up to 136 × 31 µm) or ellipsoid (up to 59 × 35 µm), with walls up to 1.5 µm thick; refractive (not clearly vascular) hyphae 2.5 - 11.0 µm wide, uncommon. | ||||||||
| lamella trama | protolog & RET type study of A. islandica: bilateral; subhymenial base dominated by intercalary inflated cells [subglobose to broadly ellipsoid (up to 35 × 26 µm) or clavate to broadly subfusiform (up to 73 × 33 µm)], but also containing occasional filamentous, undifferentiated hyphae (often diverging at a rather shallow angle); wcs = 70 - 85 µm; filamentous, undifferentiated hyphae 2.0 - 8.0 µm wide, branching, sometimes constricted at septa, with intercalary segments in central stratum occasionally inflated (ellipsoid) or partially inflated (up to 14.0 µm wide); terminal, divergent inflated cells not observed; vascular hyphae not observed. | ||||||||
| subhymenium | protolog & RET type study of A. islandica: wst-near = 95 - 120 µm (60 - 65 µm in less mature region); wst-far = 130 - 145 µm (80 - 85 µm in less mature region); 15 - 30 µm between subhymenial base and nearest base of basidium; 50 - 55 µm between subhymenial base and farthest base of basidium; comprising inflated cells and partially inflated and uninflated hyphal segments and branched elements, because of cell width (in particular of the less inflated elements) sometimes giving pseudoparenchymatous impression, but branching structure always evident, with elements often having major diameter perpendicular to central stratum, with basidia arising from cells of all types, with uninflated elements predominant in less mature regions of lamellae; clamps not observed after extensive search. | ||||||||
| basidia | protolog & RET type study of A. islandica: 49 - 83 (-92) × 12.5 - 17.0 µm, dominantly 4-sterigmate, rarely 2- or 1-sterigmate; clamps not observed after extensive search. | ||||||||
| universal veil | protolog & RET type study of A. islandica: On pileus: absent. On stipe base, exterior surface: more orangish yellow than interior; filamentous, undifferentiated hyphae 2.0 - 8.0 µm wide, largely longitudinally oriented, often in rather broad fascicles, extensively gelatinized to partially gelatinized; inflated cells not observed; vascular hyphae 4.5 - 13.0 µm wide, infrequent, fragmented. On stipe base, interior: rather badly collapsed in holotype; filamentous, undifferentiated hyphae 2.8 - 13.0 µm wide, branching, often in fascicles (many sublongitudinally oriented, others interwoven), plentiful to dominating, occasionally with yellowish subrefractive walls, with walls thin or up to 0.5+ µm thick; inflated cells broadly clavate, singly terminal, plentiful, up to 142 × 54 µm, with walls up to 1.0± µm thick; vascular hyphae 4.5 - 8.0 µm wide, branching, scarce. On stipe base, inner surface: like interior, but more yellowish, slightly gelatinized, and having a greater concentration of (longitudinally oriented) hyphae. | ||||||||
| stipe context | protolog & RET type study of A. islandica: longitudinally acrophysalidic; filamentous, undifferentiated hyphae 2.8 - 10.8 µm wide, branching, often in fascicles, plentiful; acrophysalides dominating, up to 400 × 36 µm (but most less than 200 µm long), with walls up to 1.0 µm thick; vascular hyphae 5.6 - 19.2 µm wide, common (including at/near surface), frequently loosely coiled or twisted, with common abrupt constrictions (as in pileipellis). | ||||||||
| partial veil |
protolog & RET type study of A. islandica: [Note: RET is not at all sure that the tissue here described is truly the analog of a partial veil as seen, for example, in the species of Amanita sect. Caesareae; however, this field seems an appropriate place in which to put my data.] filamentous, undifferentiated hyphae 2.5 - 10.0 µm wide, frequently branching, with walls thin to slightly thickened, in a loose tangle, loosely coiling, sometimes with subrefractive yellowish walls, plentiful to locally dominant, often in loosely associated fascicles (many sublongitudinally oriented) of few members; inflated cells plentiful to locally dominant, without dominant orientation, singly terminal, sometimes with subterminal hyphal segment partially inflated (up to 13.0 µm wide), subcylindric to narrowly clavate to clavate (up to 88 × 18.5 µm) or broadly clavate to subpyriform (up to 54 × 30 µm), with walls thin or up to 0.5 µm thick; vascular hyphae not observed. | ||||||||
| lamella edge tissue | protolog & RET type study of A. islandica: not described. | ||||||||
| basidiospores |
protolog & RET type study of A. islandica: [40/1/1] (9.5-) 10.5 - 13.8 (-15.0) × (8.0-) 9.0 - 11.8 (-14.5) µm, (L = 12.0 µm; W = 10.5 µm; Q = (1.03-) 1.06 - 1.27 (-1.53); Q = 1.14), hyaline, colorless, smooth, thin-walled, inamyloid, subglobose to broadly ellipsoid, infrequently globose, infrequently ellipsoid, rarely subtriangular in side view, adaxially flattened, often expanded at one end; apiculus sublateral, cylindric to narrowly truncate-conic, prominent; contents dominantly monoguttulate, occasionally multiguttulate; white to whitish [to pale cream-ivory] in deposit. composite from all material studied: [110/4/4] (8.8-) 9.3 - 13.2 (-15.0) × (8.0-) 8.4 - 11.5 (-14.5) µm, (L = 9.8 - 12.0 µm; L' = 11.2 µm; W = 9.0 - 10.5 µm; W' = 9.9 µm; Q = (1.03-) 1.05 - 1.30 (-1.53); Q = 1.09 - 1.19; Q' = 1.14). | ||||||||
| ecology |
protolog & RET type study of A. islandica: Iceland: Solitary. In grassy, sometimes open, places with Betula and conifers (all introduced). Norway: Solitary: In mixed forest in a path on a steep, stony hillside. Sweden: With Betula and Picea. | ||||||||
| material examined |
protolog & RET type study of A. islandica: ICELAND: ca. Reykjavik, Heiðmörk, s.d. J. Melot 90-16 (holotype, in herb. J. Melot). NORWAY: BUSKERUD—Røyken, Sætre, 15.viii.1999 Vesla Johansen s.n. [Tulloss 8-19-99-B] (O 63289; RET 311-1). SWEDEN: VÄSTRA GÖTALAND—former Älvsborg, Ulricehamn, 17.viii.1988 K. Soop KS-AA4 (RET 367-8, S), 8.ix.1989 K. Soop KS-AA4B (RET 367-9; S). | ||||||||
| discussion |
protolog & RET type study of A. islandica: This species has a floccose layer sheathing the uppermost several cm of the stipe. The anatomy of this layer suggests that it may be a thin, weakly structured partial veil. For example, the sublongitudinally oriented fascicles of hyphae correspond to the subradially oriented fascicles often reported for partial veil tissue, e.g., by Tulloss (1994: 379); and the rather narrow inflated cells (Fig. ??) are reminiscent of those seen in partial veils and are not like the subglobose and pyriform cells of brief existence that allow the separation of the partial veil or upper stipe from the edges of the lamellae in Amanita. Unlike the previously reviewed, large, robust taxa of section Vaginatae that were reported to bear at least occasional clamps (Tulloss, 1994), A. islandica apparently lacks basidial clamps. It also differs from these taxa by having a pileus that is entirely white at first and having striae of the pileus margin that occupy less than one-fifth of the pileus radius. The protolog states that the universal veil at the stipe base is a thick, saccate volva. The material of the universal veil on the stipe base in the portion of the holotype that I reviewed was in the form of a single large patch not attached to the stipe base; however, this is certainly an accident of collecting or preservation as indicated by review of a number of recent collections of the species. The coloration of A. islandica, its apparently somewhat fragile volva, the weakly structured sheath on the upper part of its stipe, the marked thickness of the pileus context above the stipe, and the subhymenium of mostly inflated elements suggests comparison of the present species with A. arctica. [See (Tulloss, 1994) and emendation of this species on this site.] The holotype of Amanita arctica differs from that of A. islandica in having:
There are no nrLSU sequences in UNITE or GenBank to compare to the nrLSU sequence we have for RET 367-9. The measured spores of A. arctica are, on average, proportionately slightly broader than those of A. islandica (Q’ = 1.09 vs. 1.14): Examination and sequencing of additional collections of both taxa would be very valuable. | ||||||||
| citations | —R. E. Tulloss | ||||||||
| editors | RET | ||||||||
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| name | Amanita islandica |
| bottom links |
[ Keys & Checklists ] [ Newfoundland and Labrador region list ] |
| name | Amanita islandica |
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Spore data sets and their composite
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