3.2. Taxonomy
Amanita sect. Amidella (E. J. Gilbert) Konrad and Maubl., Agaricales: 61 (1948).
Basionym: Amidella E. J. Gilbert, in Bres., Iconogr. Mycol. 27 Suppl. 1(1): 71 (1940).
Type: Amanita volvata (Peck) Lloyd, Mycol. Writ. 1(7): 9 (1898).
Notes: Species from section
Amidella have a series of remarkable characteristics, such as the color of the basidiomata changing to a brownish or reddish tone when injured, a striate and appendiculate pileal margin, the lamellae changing to a brown tone upon drying, truncate lamellulae, the amyloid basidiospores, and the absence of clamps [
2,
16,
50]. The above combination of characteristics is unique to the section
Amidella and is not found in any other section of
Amanita.
Presently, only two species of the section
Amidella have been reported from Thailand, namely
Amanita avellaneosquamosa (S. Imai) S. Imai and
A. clarisquamosa (S. Imai) S. Imai [
25]. In this study, six specimens collected from Chiang Mai and Phetchabun provinces were recognized and described as two novel species belonging to the section
Amidella.
Amanita claristriata Yuan S. Liu and S. Lumyong, sp. nov.;
Figure 2a and
Figure 3.
MycoBank number: 847954
Etymology: “claristriata”, from clarus (obvious) and striatus (grooved), indicates that this species has obvious striations on the margin of its pileus.
Holotype: THAILAND, Chiang Mai Province, Mueang District, 18°48′24.3″ N 98°54′38.1″ E, alt. 1102 m, 3 September 2020, Yuan S. Liu, STO-2020-404 (CMUB39992). GenBank accession numbers: OQ780686 (ITS), OQ780668 (nrLSU), OQ740048 (RPB2), and OQ740066 (TEF1-α).
Basidiomata medium-sized. Pileus 5.6–7.2 cm in diam., plano-convex to applanate, sometimes depressed at the center, white (1A1) to orange white (6A2); volval remnants on the pileus floccose to scaly, sometimes disappear because of rain, greyish orange (6B5–6) to brownish orange (7C5–6), densely arranged over the disk; margin inconspicuously striate at first and becoming obviously so with age, sometimes up to 0.3 R, appendiculate; context 5.0–7.0 mm wide, white (1A1), changing to orange white or pale orange (6A2–3) after injury. Lamellae free, crowded, white (1A1), becoming brown to dark brown (6F5–8) upon drying; lamellulae mostly truncate. Stipe 11.3–16.0 cm long × 0.7–1.3 cm diam. (the length includes the basal bulb), subcylindric or slightly tapering upwards, with the apex slightly expanded, white (1A1), covered with fibrous to floccose, white (1A1), greyish orange (6B3–4) to brown (6C4–6) squamules; context white (1A1), changing to orange white or pale orange (6A2–3) after injury, fistulose; basal bulb absent; volva saccate, 3.0–4.2 cm high × 1.8–2.4 cm wide, membranous, white (1A1) to greyish orange (6B5–6). Annulus absent. Odor not recorded.
Lamellar trama bilateral. Mediostratum 30–40 μm wide, consisting of abundant clavate inflated cells (45–115 × 10–20 μm); filamentous hyphae abundant, 2–8 μm wide; vascular hyphae scarce. Lateral stratum 30–40 μm thick, consisting of abundant to dominated clavate inflated cells (30–72 × 9–16 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 2–6 μm wide.
Subhymenium 20–30 μm thick, with two–three layers of subglobose or irregular cells, 9–23 × 6–16 μm.
Basidia (
Figure 3b) 33–47 × 8–11 μm, clavate, four-spored; sterigmata 3–6 μm long; basal septa lacking clamps.
Basidiospores [82/3/3] (8.0–) 9.0–11.5 × 5.0–6.0 μm, avl × avw = 10.3 × 5.3 μm, Q = (1.60–) 1.64–2.20 (–2.30), Qm = 1.95 ± 0.18, elongate to cylindrical, thin-walled, smooth, colorless to pastel yellow, amyloid (
Figure 3a).
Lamellar edge sterile, consisting of subglobose to ellipsoid or clavate inflated cells (13–45 × 8–23 μm), single or in chains of 2–3, thin-walled, colorless to pastel yellow; filamentous hyphae abundant, 3–6 μm wide, irregularly arranged.
Pileipellis 70–140 μm thick, two-layered; upper layer (30–80 μm thick) gelatinized, consisting of radially, thin-walled, colorless to pale yellow, filamentous hyphae 1–4 μm wide; lower layer (35–65 μm thick) consisting of radially and compactly arranged, filamentous hyphae 2–8 μm wide, colorless to pale yellow; vascular hyphae scarce.
Volval remnants on pileus (
Figure 3c) consisting of subradially to radially arranged elements: filamentous hyphae abundant, 2–10 μm wide, colorless pale yellow, thin-walled; inflated cells abundant, ellipsoid to clavate, 60–270 × 20–37 μm, colorless to pale yellow, thin-walled, often terminal; vascular hyphae scarce. Interior of
volval remnants on stipe base consisting of sub-longitudinally to longitudinally arranged elements: filamentous hyphae abundant, 2–10 μm wide, colorless, thin-walled; inflated cells fairly abundant, subglobose to ellipsoid or ovoid, 40–98 × 15–55 μm, colorless, thin-walled, often terminal; vascular hyphae scarce. The outer surface of volval remnants on stipe base consisting of very abundant filamentous hyphae (2–6 μm wide), mixed with scattered to fairly abundant, subglobose to ellipsoid, or ovoid inflated cells. The inner surface of volval remnants on stipe base gelatinized, similar to structure of interior part but comprising much more filamentous hyphae (1–5 μm wide).
Stipe trama consisting of longitudinally arranged, long clavate, terminal cells, 125–365 × 20–45 μm; filamentous hyphae scattered to abundant, 2–5 μm wide; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous forests dominated by Dipterocarpus and Shorea species. Basidiomata occurs in the rainy season.
Distribution: Currently known in northern Thailand.
Additional collections examined: THAILAND, Chiang Mai Province, Mueang District, alt. 1102 m, 3 September 2020, Yuan S. Liu, STO-2020-407 (SDBR-STO20-407); Yuan S. Liu, STO-2020-408 (SDBR-STO20-408).
Notes: Amanita claristriata is characterized by its medium-sized basidiomata, orange white pileus covered by floccose-felted to patchy, brownish orange volval remnants, an obvious striate margin on pileus (after maturity), the color of the basidiomata changes when injured (from white to pale orange), longer stipe (11.3–16.0 cm) covered by fibrous to floccose, brownish squamules, saccate volva remnants on the stipe base, as well as elongate to cylindrical basidiospores (9.0–11.5 × 5.0–6.0 μm, Qm = 1.95 ± 0.18).
Morphologically,
Amanita lanigera Y.Y. Cui, Q. Cai and Zhu L. Yang and
A. parvicurta Y.Y. Cui, Q. Cai and Zhu L. Yang resemble
A. claristriata.
Amanita lanigera, described from China, differs from
A. claristriata by having the non-striate pileal margin (or slightly striate), basidiomata color unchanged when injured, and larger, ellipsoid, colorless basidiospores (10.0–12.0 × 7.0–8.5 μm, Qm = 1.49 ± 0.13) [
2].
Moreover, it is remarkable that
Amanita rufobrunnescens W. Q. Deng and T. H. Li [
51] and
A. volvata [
16,
52,
53] share a particular and consistent feature with
A. claristriata, viz. the basidiomata changes to light red or pale orange after injury. However, both
A. rufobrunnescens reported from China and
A. volvata reported from America have larger basidiospores (10.0–12.0 × 5.5–6.5 μm, Qm = 1.78 ± 0.17 for
A. rufobrunnescens; 10.0–12.5 × 6.0–7.5 μm, Qm = 1.67 ± 0.11 for
A. volvata) [
2,
16,
51,
53].
Phylogenetically,
Amanita claristriata is related to
A. peckiana Kauffman and
A. pinophila Y.Y. Cui, Q. Cai and Zhu L. Yang. However, the latter two species differ from the former by not changing basidiomata color when injured, as well as larger basidiospores (9.8–13.6 × 5.6–7.0 μm for
A. peckiana; 10.0–12.0 × 5.5–7.0 μm, Qm = 1.81 ± 0.14 for
A. pinophila) [
2,
53].
Amanita fulvisquamea Yuan S. Liu and S. Lumyong, sp. nov.;
Figure 2b–d and
Figure 4.
MycoBank number: 847955
Etymology: “fulvisquamea”, from fulvus (brownish) and squameus (covered with scales), referring to the brown scales on its pileus.
Holotype: THAILAND, Phetchabun Province, Nam Nao District, 16°42′37″ N 101°35′55″ E, alt. 870 m, 21 August 2020, Yuan S. Liu, STO-2020-367 (CMUB39993). GenBank accession numbers: OQ780689 (ITS), OQ780671 (nrLSU), OQ740051 (RPB2), OQ740069 (TEF1-α), and OQ740087 (TUB).
Basidiomata small- to medium-sized. Pileus 3.0–5.8 cm in diam., plano-convex to applanate, white (1A1) with pale orange (5A3) tone; volval remnants on pileus floccose to scaly, white (1A1), greyish orange (6B4–6) to brown (6C4–6), densely arranged over the disk; margin inconspicuously striate at first and becoming obviously so with age, appendiculate; context 3.5–7.0 mm wide, white (1A1), unchanging. Lamellae free, crowded, white (1A1), becoming greyish orange (5B3–5) to brown (6E5–8) upon drying; lamellulae mostly truncate. Stipe 6.0–7.5 cm long × 0.5–1.2 cm diam. (the length includes the basal bulb), subcylindric or slightly tapering upwards, with the apex slightly expanded, white (1A1), covered with floccose, white (1A1), greyish orange (6B4–6) to brown (6C4–6) squamules; context white (1A1), unchanging, fistulose; basal bulb absent; volva saccate, 2.5–3.1 cm high × 1.8–2.7 cm wide., membranous, white (1A1) to brown (6C4–6). Annulus present, white (1A1), fugacious. Odor not recorded.
Lamellar trama bilateral. Mediostratum 25–40 μm wide, consisting of abundant clavate to oblong inflated cells (35–145 × 12–35 μm); filamentous hyphae abundant, 2–7 μm wide; vascular hyphae scarce. Lateral stratum 35–55 μm thick, consisting of abundant oblong inflated cells (22–75 ×11–32 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 3–8 μm wide.
Subhymenium 25–35 μm thick, with two–three layers of subglobose or irregular cells, 9–25 × 7–13 μm.
Basidia (
Figure 4b) 33–51 × 10–14 μm, clavate, four-spored; sterigmata 3–5 μm long; basal septa lacking clamps.
Basidiospores [81/3/3] (8.0–) 8.5–11.0 (–11.5) × (6.5–) 7.0–8.0 (–8.5) μm, avl × avw = 9.7 × 7.2 μm, Q = (1.13–) 1.20–1.57 (–1.64), Qm = 1.35 ± 0.11, broadly ellipsoid to ellipsoid, sometimes subglobose or elongate, thin-walled, smooth, colorless to pale yellow or dull yellow, amyloid (
Figure 4a).
Lamellar edge sterile, consisting of subglobose to ellipsoid or pyriform inflated cells (18–65 × 11–30 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae abundant, 2–5 μm wide, irregularly arranged.
Pileipellis 110–170 μm thick, two-layered; upper layer (80–135 μm thick) strongly gelatinized, consisting of subradially arranged, thin-walled, colorless to pale yellow, filamentous hyphae 1–8 μm wide; lower layer (20–35 μm thick) consisting of radially and compactly arranged, filamentous hyphae 2–6 μm wide, colorless to pale yellow; vascular hyphae scarce.
Volval remnants on pileus (
Figure 4c) consisting of subradially to radially arranged elements: filamentous hyphae abundant, 2–8 μm wide, colorless to pale yellow, thin-walled; inflated cells abundant, ellipsoid to clavate, 43–200 × 13–37 μm, colorless to pale yellow, thin-walled, often terminal; vascular hyphae scarce. Interior of
volval remnants on stipe base consisting of sub-longitudinally arranged elements: filamentous hyphae abundant, 2–12 μm wide, colorless, thin-walled; inflated cells abundant, subglobose to ellipsoid, 30–50 × 12–40 μm, colorless, thin-walled, often terminal; vascular hyphae scarce. The outer surface of volval remnants on stipe base consisting of very abundant filamentous hyphae (1–11 μm wide), mixed with scattered to fairly abundant, subglobose to ellipsoid, or ovoid to pyriform inflated cells. The inner surface of volval remnants on stipe base gelatinized, similar to structure of interior part but comprising much more filamentous hyphae (1–10 μm wide).
Stipe trama consists of longitudinally arranged, long clavate terminal cells, 105–320 × 16–35 μm; filamentous hyphae scattered to abundant, 2–10 μm wide; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous or coniferous forests dominated by Dipterocarpus, Shorea, and Pinus species. Basidiomata occurs in the rainy season.
Distribution: Currently known in northern Thailand.
Additional collections examined: THAILAND, Chiang Mai Province, Mae On District, alt. 1201 m, 30 July 2020, Yuan S. Liu, STO-2020-211 (SDBR-STO20-211). Phetchabun Province, Nam Nao District, alt. 870 m, 21 August 2020, Yuan S. Liu, STO-2020-377 (SDBR-STO20-377).
Notes: Amanita fulvisquamea is characterized by its small- to medium-sized basidiomata, pulverulent to floccose, or patchy and greyish orange to brown volval remnants on pileus, striate pileal margin, saccate volva remnants on the stipe base, as well as broadly ellipsoid to ellipsoid basidiospores (8.5–11.0 × 7.0–8.0 μm, Qm = 1.35 ± 0.11).
Morphologically,
Amanita fulvisquamea is easily confused with
A. clarisquamosa,
A. parvicurta, and
A. volvata due to the similar appearances, e.g., floccose to pulverulent, brownish volval remnants on the pileus; floccose, brownish squamules on the stipe, as well as saccate volva remnants on the stipe base. However,
A. clarisquamosa has much longer basidiospores, which mainly possess elongate shape, while both
A. parvicurta and
A. volvata have much narrower and elongate-shaped basidiospores [
2,
16,
53].
Phylogenetically,
Amanita brunneomaculata Y.Y. Cui, Q. Cai and Zhu L. Yang is closely related to
A. fulvisquamea. However, the former differs from the latter by having a distinctly spotted pileus, as well as much longer basidiospores (10.0–13.0 × 6.5–8.0 μm, Qm = 1.65 ± 0.19) [
2].
Amanita lanigera is morphologically similar and phylogenetically related to
A. fulvisquamea. However,
A. lanigera, originally reported from China, has thicker pileipellis (75–230 μm), larger inflated terminal cells (80–520 × 15–45 μm) in the stipe trama, as well as longer, ellipsoid, and colorless basidiospores (10.0–12.0 × 7.0–8.5 μm, Qm = 1.35 ± 0.11) [
2].
Amanita sect. Phalloideae (Fr.) Quél., Mém. Soc. Emul. Montbéliard, Ser. II, 5: 66 (1872).
Basionym: Amanita [sect.] Phalloideae Fr., Monogr. Amanit. Sueciae: 3 (1854).
Lectotype: Amanita phalloides (Vaill. ex Fr.) Link., Handbuch zur Erkennung der Nutzbarsten und am häufigsten vorkommenden Gewächse: 272 (1833).
Notes: According to previous studies,
Amanita sect.
Phalloideae phylogenetically comprises three subclades that are well supported in phylogenetic analyses and by morphological evidence. Our multi-locus phylogenetic analysis also presented the same result. These three subclades may be treated as subsections or new sections [
2,
4,
26,
54] in the future.
Up to now, six taxa of section
Phalloideae have been reported from Thailand, namely
Amanita ballerina Raspé, Thongbai and K.D. Hyde,
A. brunneitoxicaria Thongbai, Raspé and K.D. Hyde,
A. fuliginea Hongo,
A. fuligineoides P. Zhang and Zhu L. Yang,
A. rimosa P. Zhang and Zhu L. Yang and
A. zangii Zhu L. Yang, T.H. Li and X.L. Wu [
25,
26,
29]. One more taxon is recognized in our phylogenetic analysis, and here it is described as a new species based on morphological evidence as well.
Amanita albifragilis Yuan S. Liu and S. Lumyong, sp. nov.;
Figure 2e–f and
Figure 5.
MycoBank number: 847956
Etymology: “albifragilis”, from albus (whitish) and fragilis (brittle), refers to the white fruiting body and the thin and brittle surface of the pileus.
Holotype: THAILAND, Sakon Nakhon Province, Kut Bak District, 17°6′4″ N 103°54′32″ E, alt. 205 m, 15 August 2020, Yuan S. Liu, STO-2020-300 (CMUB39994). GenBank accession numbers: OQ780692 (ITS), OQ780674 (nrLSU), and OQ740072 (TEF1-α).
Basidiomata small- to medium-sized. Pileus 3.2–5.2 cm in diam., plano-convex to applanate, often depressed at center, surface thin and fragile, white (1A1); volval remnants on pileus absent; margin non-striate, non-appendiculate; context 1.5–2.5 mm wide, white (1A1), unchanging. Lamellae free, crowded, white (1A1); lamellulae mostly truncate. Stipe 5.4–8.0 cm long × 0.5–0.6 cm diam. (the length includes the basal bulb), subcylindric or slightly tapering upwards, with apex slightly expanded, white (1A1), covered with fibrous, white (1A1), squamules; context white (1A1), unchanging, fistulose to solid; basal bulb subglobose; volva limbate, 1.3–1.8 cm high × 1.4–1.8 cm wide., membranous, white (1A1). Annulus subapical, membranous, white (1A1), persistent. Odor not recorded.
Lamellar trama bilateral. Mediostratum 20–30 μm wide, consists of abundant ellipsoid to elongate inflated cells (60–108 × 15–32 μm); filamentous hyphae abundant, 2–8 μm wide; vascular hyphae scarce. The lateral stratum consists of abundant ellipsoid to clavate inflated cells (30–60 × 11–22 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 2–6 μm wide.
Subhymenium 20–30 μm thick, with two–three layers of subglobose to ellipsoid or irregular cells, 7–19 × 6–13 μm.
Basidia (
Figure 5b) 28–45 × 8–12 μm, clavate, four-spored; sterigmata 3–6 μm long; basal septa lacking clamps.
Basidiospores [69/2/2] (7.0–) 8.0–9.0 (–10.5) × 6.0–7.0 (–9.0) μm, avl × avw = 8.5 × 6.8 μm, Q = (1.13–) 1.14–1.39 (–1.50), Qm = 1.26 ± 0.09, broadly ellipsoid, sometimes subglobose, thin-walled, smooth, colorless, and amyloid (
Figure 5a).
Lamellar edge sterile, consisting of subglobose to ellipsoid or clavate inflated cells (14–50 × 12–28 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae scattered, 1–3 μm wide, irregularly arranged.
Pileipellis 60–110 μm thick, two-layered; upper layer (20–40 μm thick) slightly gelatinized, consisting of subradially arranged, thin-walled, colorless, filamentous hyphae 2–8 μm wide; lower layer (30–70 μm thick) consisting of radially and compactly arranged, filamentous hyphae 2–8 μm wide, colorless; vascular hyphae scarce. The interior of
volval remnants on the stipe base consists of sub-longitudinally to irregularly arranged elements: filamentous hyphae very abundant, 3–11 μm wide, colorless, thin-walled; inflated cells scarce to scattered, clavate, 70–110 × 10–36 μm, colorless, thin-walled; vascular hyphae scarce. The outer surface of volval remnants on stipe base (
Figure 5c) predominately consists of very abundant filamentous hyphae (3–12 μm wide), mixed with scarce, clavate inflated cells. The inner surface of volval remnants on the stipe base gelatinized, similar to structure of interior part but comprising much more filamentous hyphae (3–9 μm wide).
Stipe trama consists of longitudinally arranged, abundant, long clavate terminal cells (80–285 × 12–23 μm); filamentous hyphae abundant to very abundant, 2–9 μm wide; vascular hyphae scarce.
Annulus consists of radially arranged elements: inflated cells scattered, clavate, often terminal, 35–75 × 9–17 μm, colorless, thin-walled; filamentous hyphae very abundant to predominant, 2–9 μm wide, colorless, thin-walled; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous forests dominated by Dipterocarpus and Shorea species. Basidiomata occurs in the rainy season.
Distribution: Currently known in northeastern Thailand.
Additional collections examined: THAILAND, Sakon Nakhon Province, Kut Bak District, alt. 205 m, 15 August 2020, Yuan S. Liu, STO-2020-304 (SDBR-STO20-304).
Notes: Amanita albifragilis is characterized by its small- to medium-sized basidiomata, slightly depressed pileal center, the thin and fragile surface of the pileus, a non-striate pileal margin, subglobose stipe base surrounded by limbate volva remnants, subapical and persistent annulus, as well as the broadly ellipsoid amyloid basidiospores (8.0–9.0 × 6.0–7.0 μm, Qm = 1.26 ± 0.09).
At first sight,
Amanita rimosa, originally reported from China [
55], resembles the newly described species rather strongly. Both species share a number of similar or identical features, e.g., a small and white basidioma, a smooth pileus with slightly rimose margin, the limbate volva remnants on the stipe base, and a membranous and persistent annulus [
2,
19,
55]. However,
A. rimosa has globose to subglobose basidiospores (7.0–8.5 × 6.5–8.0 μm, Qm = 1.08 ± 0.05) and a different structure of pileipellis containing more abundant ellipsoid to clavate inflated cells [
2,
19,
55].
Except for
Amanita rimosa, there are a number of taxa that have white basidiomata in section
Phalloideae, e.g.,
A. exitialis Zhu L. Yang and T. H. Li,
A. parviexitialis Q. Cai, Zhu L. Yang and Y.Y. Cui,
A. virosa Bertillon and
A. subjunquillea S. Imai. Among the above taxa,
A. parviexitialis is easily confused with
A.
albifragilis due to its small basidioma, a smooth and depressed pileus, and the limbate volva remnants on the stipe base. However,
A. parviexitialis usually has brownish tone in the pileal center, two-spored basidia, as well as much wider, subglobose basidiospores (7.5–9.5 × 7.0–9.0 μm, Qm = 1.09 ± 0.05) [
2,
19,
56].
Phylogenetically,
Amanita albifragilis is closely related to
A. griseorosea Q. Cai, Zhu L. Yang and Y.Y. Cui and
A. molliuscula Q. Cai, Zhu L. Yang and Y.Y. Cui.
Amanita griseorosea can be easily distinguished from
A. albifragilis by having a grayish-brown pileus with dark-gray fibrils and pinkish lamellae [
2,
19,
38,
56]. Compared to the newly described species,
A. molliuscula has much more abundantly inflated cells in structures of pileipellis and in the interior of volval remnants on stipe base, as well as the wider and globose to subglobose basidiospores (7.5–9.0 × 7.0–8.0 μm, Qm = 1.07 ± 0.06) [
2,
38,
56].
Amanita sect. Roanokenses Singer ex Singer, Sydowia 15: 67 (1962).
Synonym: Amanita subsect. Limbatulae Bas, Persoonia 5: 528 (1969).
Type: Amanita roanokensis Coker, J. Elisha Mitchell scient. Soc. 43: 141 (1927).
Notes:
Amanita sect.
Roanokenses is one of the most species-diverse sections in
Amanita subgen.
Amanitina. To date, nine species have been reported from Thailand, namely
A. alboflavescens Hongo,
A. atrobrunnea Thongbai, Raspé and K.D. Hyde,
Amanita cf.
oberwinkleriana,
A. hongoi Bas,
A. japonica Hongo ex Bas,
A. macrocarpa W. Q. Deng, T. H. Li and Zhu L. Yang,
A. manginiana sensu W.F. Chiu,
A. pseudoporphyria Hongo and
A. virgineoides Bas [
2,
25,
26,
28]. In this study, four taxa belonging to the section
Roanokenses were recognized and are presented below.
Amanita caojizong Zhu L. Yang, Y.Y. Cui and Q. Cai, Fungal Divers. 91: 138 (2018).
Figure 2g and
Figure 6.
Basidiomata large. Pileus 9.5–12.0 cm diam., convex to plano-convex, milk white to greyish yellow (1B2–4) or greyish brown (5E3), possessing innate dark-grey radiating fibrils; volval remnants on pileus often absent; margin non-striate, appendiculate; context 8–9 mm wide, white (1A1), unchanging. Lamellae free, crowded, white (1A1); lamellulae attenuate. Stipe 14.3–20.0 cm long × 1.5–1.7 cm diam. The length includes the basal bulb, cylindrical or slightly tapering upwards with apex slightly expanded, white (1A1), covered with fibrous squamules; context solid, white (1A1); basal part 2.2–3.2 cm diam., fusiform to clavate; volval remnants on stipe base sheathed, membranous, with free limb up to 6.1 cm high, white (1A1). Annulus apical, white, fragile, and fugacious when mature. Odor not recorded.
Lamellar trama bilateral. Mediostratum 20–40 μm wide, consisting of abundant ellipsoid to elongate inflated cells (53–90 × 13–22 μm); filamentous hyphae abundant, 2–6 μm wide; vascular hyphae scarce. Lateral stratum 20–30 μm wide, consisting of abundant elongate to clavate inflated cells (36–65 × 12–22 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 3–5 μm wide.
Subhymenium 20–30 μm thick, with two–three layers of subglobose, ovoid to ellipsoid, or irregular cells, 6–25 × 5–16 μm.
Basidia (
Figure 6b) 32–45 × 8–10 μm, clavate, four-spored; sterigmata up to 4–5 μm long; basal septa lacking clamps.
Basidiospores [75/3/3] (6.0–) 6.5–8.0 (–9.0) × 5.0–7.0 μm, avl × avw = 7.5 × 6.0 μm, Q = (1.00–) 1.14–1.36 (–1.50) μm, Qm = 1.25 ± 0.10, broadly ellipsoid, sometimes globose to subglobose, thin-walled, smooth, colorless, amyloid (
Figure 6a).
Lamellar edge sterile, consisting of subglobose to ellipsoid inflated cells (9–17 × 8–14 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae abundant, 2–7 μm wide, irregularly arranged.
Pileipellis 90–150 μm thick, two-layered; upper layer (30–90 μm thick) strongly gelatinized, consisting of radially, thin-walled, colorless or light brownish, filamentous hyphae 2–5 μm wide; lower layer (45–110 μm thick) consisting of radially and compactly arranged filamentous hyphae 2–7 (–12) μm wide, yellowish to brownish; vascular hyphae scarce. The inner part of
volval remnants on the stipe base consists of longitudinally arranged elements: filamentous hyphae predominant, 2–8 μm wide, colorless, thin-walled, branching; inflated cells scarce to scattered, ellipsoid to clavate, sometimes subglobose, 65–125 × 13–30 μm, colorless, thin-walled, interjacent, or terminal; vascular hyphae scarce. Th outer surface of volval remnants on the stipe base (
Figure 6c) is similar to the inner part but with more abundant filamentous hyphae. The inner surface of volval remnants on the stipe base is similar to the interior part but slightly gelatinized.
Stipe trama consists of longitudinally arranged, long clavate terminal cells, 130–220 × 15–30 μm; filamentous hyphae abundant, 2–10 μm wide; vascular hyphae scarce.
Annulus consists of loosely arranged, interwoven elements: inflated cells abundant, globose, subglobose to pyriform, 15–55 × 13–48 μm, colorless, thin-walled; filamentous hyphae fairly abundant, 1–6 μm wide, colorless, thin-walled; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous forests dominated by Dipterocarpus and Shorea species. Basidiomata occurs in the rainy season.
Distribution: This species is currently known in China [
2,
57], Japan [
58], Korea [
59], and Thailand ([
26], this study).
Specimens examined: THAILAND, Chiang Mai Province, Mae Taeng District, alt. 720 m, 9 August 2019, Yuan S. Liu, STO-2019-473 (SDBR-STO19-473); Mae On District, alt. 753 m, 6 July 2020, Yuan S. Liu, STO-2020-120 (SDBR-STO20-120). Chiang Rai Province, Mae Fa Luang District, alt. 1236 m, 10 July 2020, Yuan S. Liu, STO-2020-169 (SDBR-STO20-169).
Notes:
Amanita caojizong, reported from China, is a common edible mushroom found in Yunnan province. It is morphologically similar to a number of taxa, such as
A. pseudoporphyria,
A. pseudomanginiana Q. Cai, Y.Y. Cui and Zhu L. Yang,
A. griseoturcosa T. Oda, C. Tanaka and Tsuda,
A. roseolifolia Y.Y. Cui, Q. Cai and Zhu L. Yang and
A. modesta Corner and Bas. Detailed comparisons between
A. caojizong and these similar species can be found in Cui et al. [
2]. It is worth noting that our Thai collections had a much wider color range on the pileus, i.e., milk white to greyish yellow or greyish brown.
Amanita griseofarinosa Hongo, Mem. Fac. Lib. Arts Shiga Univ. Nat. Sci. 11: 39 (1961).
Figure 2h and
Figure 7.
Basidiomata small- to medium-sized. Pileus 3.5–6.5 cm diam., convex to plano-convex, or applanate to plano-concave, light grey (4C1–2) to brownish grey (4D1–2); volval remnants on pileus floccose to pulverulent, brownish grey (4D2–3), yellowish (5D3–5) to yellowish brown (5E4–5), densely arranged on the disc; margin non-striate, appendiculate; context 3–4.5 mm wide, white (1A1), unchanging. Lamellae free, crowded, white (1A1); lamellulae attenuate. Stipe 7.2–12.0 cm long × 0.5–1.2 cm diam. (the length includes the basal bulb), cylindrical, densely covered by floccose to pulverulent yellowish-white (4A2) to orange-white (5A2) squamules; context stuffed, white (1A1); basal part 0.9–1.8 cm diam., clavate to ventricose, upper part covered with floccose to pulverulent, yellowish-white (4A2) to orange-white (5A2) volval remnants. Annulus fragile and fugacious. Odor not recorded.
Lamellar trama bilateral. Mediostratum 25–35 μm wide, consisting of abundant ellipsoid inflated cells (45–95 × 10–22 μm); filamentous hyphae abundant, 2–7 (–11) μm wide; vascular hyphae scarce. Lateral stratum 20–30 μm wide, consisting of abundant clavate inflated cells (35–85 × 8–25 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 3–7 μm wide.
Subhymenium 20–30 μm thick, with two–three layers of subglobose to ellipsoid or irregular cells, 6–20 × 6–12 μm.
Basidia (
Figure 7b) 40–56 × 11–13 μm, clavate, four-spored; sterigmata up to 3–5 μm long; basal septa lacking clamps.
Basidiospores [68/2/2] (7.0–) 7.5–10.0 (–11.0) × (6.0–) 6.5–8.5 (–9.0) μm, avl × avw = 8.6 × 7.4 μm, Q = (1.00–)1.06–1.31 (–1.33) μm, Qm = 1.17 ± 0.09, mainly subglobose to broadly ellipsoid, sometimes globose or ellipsoid, thin-walled, smooth, colorless, amyloid (
Figure 7a).
Lamellar edge sterile and consists of subglobose to ellipsoid inflated cells (15–33 × 10–30 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae abundant, 2–6 μm wide, irregularly arranged.
Pileipellis 50–100 μm thick, consisting of radially and compactly, thin-walled, colorless to light brownish, filamentous hyphae 2–5 μm wide, with its outer-surface hyphae loosely and irregularly arranged; vascular hyphae scarce to scattered.
Volval remnants on pileus (
Figure 7c) composed of abundant irregularly arranged filamentous hyphae 2–7 μm wide, mixed with abundant to predominant subglobose, or broadly clavate to fusiform inflated cells (15–53 × 10–40 μm).
Volval remnants on stipe base similar to structure of volval remnants on pileus, predominately composed of irregularly arranged subglobose, or broadly clavate to fusiform inflated cells (9–50 × 8–32 μm), mixed with abundant filamentous hyphae (2–7 μm wide).
Stipe trama consists of abundant longitudinally arranged, long clavate terminal cells, 80–220 × 19–30 μm; filamentous hyphae abundant, 3–10 μm wide; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous forests dominated by Dipterocarpus and Shorea species. Basidiomata occurs in the rainy season.
Distribution: This species is currently known in China [
2,
18,
19], Japan [
16,
60,
61], Korea [
62], and Thailand [this study].
Specimens examined: THAILAND, Chiang Mai Province, Mae Taeng District, alt. 1077 m, 31 May 2020, Yuan S. Liu, STO-2020-8 (SDBR-STO20-08); Yuan S. Liu, STO-2020-9 (SDBR-STO20-09).
Notes:
Amanita griseofarinosa was first reported from Japan [
60] and was then found in China and Korea [
2,
18,
19,
62]. Our two specimens possess small- to medium-sized basidiomata, pileus and stipe densely covered by floccose to pulverulent, brownish-grey or yellowish-white squamules, appendiculate margin, attenuate lamellulae, and fragile and fugacious annulus. All these features are consistent with the type specimen.
Morphologically, the species is similar to
Amanita cf.
griseofarinosa (HKAS 79587) and
A. vestita Corner and Bas on account of brownish-gray basidiomata, and pulverulent volval remnants densely pervade the surface of the pileus and stipe [
2,
15,
19]. However,
Amanita cf.
griseofarinosa differs from
A. griseofarinosa in its original sense by having clamps, as well as the much wider and globose to subglobose basidiospores (8.5–10.5 × 8.5–10.0 μm, Qm = 1.04 ± 0.04) [
2,
19]. Moreover,
Amanita cf.
griseofarinosa is phylogenetically distinct from
A. griseofarinosa [
2].
Amanita vestita, reported from Singapore, is distinguished from
A.
griseofarinosa by having small basidiomata, slightly depressed pileal center, and much narrower basidiospores (7.5–9.0 × 5.5–6.5 μm) [
15].
Undoubtedly,
Amanita berkeleyi (Hook. f.) Bas, originally described from India, is closely related to
A. griseofarinosa [
16]. However,
A. berkeleyi possesses large to very large basidiomata, felted-pulverulent to crust-like volva remnants on its pileus, and much wider basidiospores (8.0–10.5 × 6.5–9.5 μm) [
16].
Amanita cinereovelata Hosen, reported from Bangladesh [
63], is phylogenetically related and morphologically similar to
A. griseofarinosa. However,
A. cinereovelata differs by having a thicker pileipellis (up to 290 μm), globose to subglobose basidiospores (9.0–10.0 × 8.0–9.0 μm, Qm = 1.12 ± 0.05), and the presence of clamps [
63].
Amanita neoovoidea Hongo, Mem. Shiga Univ. 25: 57 (1975).
Figure 2i and
Figure 8.
Basidiomata large. Pileus 9.0–10.0 cm diam., convex to plano-convex, white (1A1) to yellowish white (1A2); volval remnants on pileus consisting of two layers: outer layer membranous, yellowish white to pale yellow (1A2–3); inner layer floccose to pulverulent, white (1A1); margin non-striate, appendiculate; context 8.5–10.0 mm wide, white (1A1), unchanging. Lamellae free, crowded, white (1A1); lamellulae attenuate. Stipe 12.0–13.5 cm long × 1.5–1.6 cm diam. (the length includes the basal bulb), cylindrical, densely covered by floccose to pulverulent white (1A1) squamules; context solid, white (1A1); basal part 2.6–3.0 cm diam., fusiform to ventricose; volval remnants on stipe base yellowish white (3A2), arranged in incomplete belts or with a recurved friable limb. Annulus subapical, white (1A1), fragile and fugacious. Odor not recorded.
Lamellar trama bilateral. Mediostratum 25–40 μm wide, consisting of abundant clavate to fusiform inflated cells (35–110 × 12–20 μm); filamentous hyphae abundant, 2–6 μm wide; vascular hyphae scarce. Lateral stratum 20–30 μm wide, consisting of abundant elongate to clavate inflated cells (20–145 × 12–30 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 3–7 μm wide.
Subhymenium 20–30 μm thick, with two–three layers of subglobose, ovoid to ellipsoid or irregular cells, 6–27 × 6–16 μm.
Basidia (
Figure 8b) 40–55 × 10–12 μm, clavate, four-spored; sterigmata up to 3–5 μm long; basal septa lacking clamps.
Basidiospores [52/2/2] 7.0–10.0 × 5.0–7.0 μm, avl × avw = 8.5 × 6.1 μm, Q = (1.14–)1.21–1.67 (–1.70) μm, Qm = 1.41 ± 0.12, broadly ellipsoid, sometimes subglobose or elongate, thin-walled, smooth, colorless, amyloid (
Figure 8a).
Lamellar edge sterile, consisting of pyriform to subglobose or clavate inflated cells (27–50 × 18–36 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae abundant, 2–5 μm wide, irregularly arranged.
Pileipellis 45–120 μm thick, consisting of radial, strongly gelatinized, colorless filamentous hyphae (2–6 μm wide); vascular hyphae scarce.
Volval remnants on pileus (
Figure 8c) consist of two layers. The outer layer of volval remnants on the pileus consists of more or less radially arranged elements: inflated cells (45–173 × 15–32 μm) fairly abundant to abundant; filamentous hyphae (2–9 μm wide) very abundant; vascular hyphae scarce. The inner layer of volval remnants on the pileus consists of irregularly arranged elements: inflated cells (14–83 × 10–50 μm) abundant to predominant, subglobose to clavate; filamentous hyphae (3–8 μm wide) abundant; vascular hyphae scarce.
Volval remnants on stipe base composed of irregularly to vertical-arranged elements: inflated cells (36–105 × 16–25 μm) fairly abundant to abundant; filamentous hyphae (1.5–7.0 μm wide) very abundant to dominate; vascular hyphae scarce.
Stipe trama consists of longitudinally arranged, long clavate terminal cells, 180–240 × 13–25 μm; filamentous hyphae abundant, 3–10 μm wide; vascular hyphae scarce.
Annulus consists of loosely, irregularly arranged elements: inflated cells abundant, subglobose, ellipsoid to clavate, 23–70 × 15–32 μm, colorless, thin-walled; filamentsous hyphae scarce to fairly abundant, 1.5–5.0 μm wide, colorless, thin-walled; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous forests dominated by Dipterocarpus and Shorea species. Basidiomata occurs in the rainy season.
Distribution: This species is currently known in China [
2,
17,
18,
19], Nepal [
64], Japan [
64,
65], Korea [
66], and Thailand (this study).
Specimens examined: THAILAND, Chiang Mai Province, Mae On District, alt. 704 m, 6 July 2020, Yuan S. Liu, STO-2020-110 (SDBR-STO20-110); Mae Taeng District, alt. 720 m, 9 August 2019, Yuan S. Liu, STO-2019-503 (SDBR-STO19-503).
Notes:
Amanita neoovoidea, originally described from Japan [
65], is characterized by medium-sized to large basidiomata, pileal volval remnants arranged in two layers, with the outer layer being membranous and inner layer being floccose to pulverulent, appendiculate pileal margin, stipe densely covered by floccose to pulverulent squamules, with incomplete belts or recurved friable limb remnants on the stipe base, and a fragile and fugacious annulus. Our Thai materials are consistent with all the features above.
Morphologically,
Amanita duplex Corner and Bas, reported from Singapore, is undoubtedly similar to this species. Moreover, in our phylogenetic analysis,
A. neoovoidea is related to
A. pseudomanginiana,
A. pseudoporphyria, and
A. atrobrunnea. Detailed comparisons between
A. neoovoidea and the four related species above can be found in previous studies [
2,
18].
Amanita oberwinkleriana Zhu L. Yang and Yoshim. Doi, Bull. Natn. Sci. Mus. Tokyo 25 (3): 120 (1999).
Figure 2j and
Figure 9.
Basidiomata small- to medium-sized. Pileus 4.5–6.0 cm diam., plano-convex to applanate, sometimes plano-concave, smooth, white (1A1), often yellowish white (1A2) to pale yellow (4A2–3) in the center; volval remnants on pileus often absent; margin non-striate, sometimes with inconspicuous stripes (ca. 0.2–0.3 R), non-appendiculate; context 2.0–4.0 mm wide, white (1A1), unchanging. Lamellae free, crowded, white to yellowish white (1A1–2); lamellulae attenuate. Stipe 8.2–9.5 cm long × 0.7–1.0 cm diam. (the length includes the basal bulb), cylindrical, covered by white (1A1), fibrous to tomentose squamules; context fistulose, white (1A1); basal part 1.6–2.0 cm diam., fusiform to napiform; volval remnants on stipe base limbate, membranous, with free limb up to ca. 1.5 cm high, both surfaces white (1A1). Annulus subapical, membranous, white (1A1). Odor not recorded.
Lamellar trama bilateral. Mediostratum 25–30 μm wide, consisting of abundant ellipsoid inflated cells (48–105 × 13–23 μm); filamentous hyphae abundant, 3–8 μm wide; vascular hyphae scarce. Lateral stratum 25–30 μm wide, consisting of abundant ellipsoid to clavate inflated cells (32–60 × 12–25 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 3–7 μm wide.
Subhymenium 30–40 μm thick, with two–three layers of subglobose, ovoid to ellipsoid, or irregular cells, 10–20 × 7–17 μm.
Basidia (
Figure 9b) 35–44 × 9–11 μm, clavate, four-spored; sterigmata up to 4–6 μm long; basal septa lacking clamps.
Basidiospores [52/2/2] (7.5–) 8.0–10.0 (–11.0) × 6.0–7.5 (–8.0) μm, avl × avw = 9.0 × 6.8 μm, Q = 1.20–1.50 μm, Qm = 1.33 ± 0.09, broadly ellipsoid to ellipsoid, thin-walled, smooth, colorless, amyloid (
Figure 9a).
Lamellar edge sterile, consisting of subglobose to ellipsoid inflated cells (12–37 × 9–25 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae fairly abundant, 3–5 μm wide, irregularly arranged.
Pileipellis 65–90 μm thick, two-layered; upper layer (30–60 μm thick) strongly gelatinized, consisting of radial, thinwalled, colorless, filamentous hyphae 2–4 μm wide; lower layer (30–35 μm thick) consisting of radially and compactly arranged, filamentous hyphae 2–6 μm wide, colorless; vascular hyphae scarce.
Volval remnants on pileus (
Figure 9c) consisting of irregularly arranged elements: inflated cell (23–48 × 20–35 μm), fairly abundant, subglobose to ellipsoid, single or in chains of two–three, colorless; filamentous hyphae (3–10 μm wide) abundant to dominate, colorless or light yellow; vascular hyphae scarce. Inner part of
volval remnants on stipe base consisting of longitudinally arranged elements: filamentous hyphae very abundant to predominant, 1–8 μm wide, colorless, thin-walled; inflated cells fairly abundant to abundant, subglobose to ovoid, or ellipsoid, 23–55 × 18–37 μm, colorless, thin-walled; vascular hyphae scarce. The outer surface of volval remnants on stipe base similar to structure of interior part but with more abundant inflated cells. Inner surface gelatinized, similar to structure of interior part but with a few inflated cells.
Stipe trama consists of longitudinally arranged, long clavate terminal cells, 170–310 × 16–27 μm; filamentous hyphae abundant, 3–10 μm wide; vascular hyphae scarce.
Annulus consisting of loosely arranged, interwoven elements: inflated cells abundant, pyriform to subglobose, 16–43 × 12–24 μm, single or in chains of two–three, colorless, thin-walled; filamentous hyphae scarce to fairly abundant, 2–8 μm wide, colorless, thin-walled; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous forests dominated by Dipterocarpus and Shorea species. Basidiomata occurs in the rainy season.
Distribution: This species is currently known in China [
2,
18,
19,
67], India [
68], Japan [
61], Korea [
20], and Thailand ([
26], this study).
Specimens examined: THAILAND, Chiang Mai Province, Mueang Chiang Mai District, alt. 1143 m, 3 August 2019, Yuan S. Liu, STO-2019-359 (SDBR-STO19-359); Yuan S. Liu, STO-2019-372 (SDBR-STO19-372).
Notes:
Amanita oberwinkleriana was firstly reported from Japan [
61] and has also been found in other Asian countries, e.g., China, India, Korea, and Thailand [
2,
18,
19,
20,
26,
67,
68]. It is characterized by small- to medium-sized basidiomata, a smooth and white pileus often tinged yellowish in the center, non-appendiculate pileal margin, attenuate lamellulae, fusiform to napiform stipe base surrounded by limbate volval remnants, as well as the membranous annulus. Our Thai materials are consistent with all the above features.
Morphologically,
Amanita oberwinkleriana can be easily confused with a number of species, having a white and smooth pileus, limbate volval remnants on the stipe base, and a membranous annulus, e.g.,
A. exitialis,
A. rimosa, and
A. virosa. However,
A. exitialis distinctly differs from the newly described species by having two-spored basidia and much larger basidiospores (9.5–12.0 × 9.0–11.5 μm, Qm = 1.08 ± 0.04) [
2,
18,
19,
20,
67].
Amanita rimosa can be distinguished from
A.
oberwinkleriana by having fissured pileal margin, as well as smaller and globose to subglobose basidiospores (7.0–8.5 × 6.5–8.0 μm, Qm = 1.08 ± 0.05) [
2,
19,
55].
Amanita virosa differs by having obvious and concolorous squamules on its stipe, as well as much wider and globose to subglobose basidiospores (8.0–11.0 × 8.0–10.0 μm, Qm = 1.07 ± 0.05) [
2,
19].
Phylogenetically,
Amanita oberwinkleriana is related to
A. rubiginosa Q. Cai, Y.Y. Cui and Zhu L. Yang,
A. avellaneifolia Zhu L. Yang, Y.Y. Cui and Q. Cai, and
A. modesta. However, this species distinctly differs from the latter three taxa by its small- to medium-sized basidiomata, as well as a smooth and white pileus [
2,
15,
19].
Amanita sect. Validae (Fr.) Quél., Mém. Soc. Emul. Montbéliard, Ser. II, 5: 69 (1872).
Basionym: Agaricus sect. Validae Fr., Monogr. Amanit. Sueciea: 10 (1854).
Lectotype: Amanita excelsa (Fr.) Bertill., Dictionnaire encyclopédique des sciences médicales 1 (3): 499 (1866).
Notes: Previously, six taxa belonging to
Amanita sect.
Validae have been reported from Thailand, namely
A. castanea Thongbai, Tulloss, Raspé and K.D. Hyde,
Amanita cf.
spissacea S. Imai,
A. flavipes S. Imai sensu lato,
A. fritillaria (Berk.) Sacc.,
A. sculpta Corner and Bas, and
A. sinocitrina Zhu L. Yang, Zuo H. Chen and Z.G. Zhang [
25,
26,
29]. In this study,
A. cacaina L.P. Tang, T. Huang and N.K. Zeng and
A. citrinoannulata Y.Y. Cui, Q. Cai and Zhu L. Yang are recognized and reported as two new records in Thailand on the basis of the phylogenetic and morphological analyses.
Amanita cacaina L.P. Tang, T. Huang and N.K. Zeng, Frontiers Microbiol. 13: 3 (2023).
Figure 2k and
Figure 10.
Basidiomata is very large. Pileus 18.0–18.6 cm diam., plano-convex to applanate, brownish orange (7C3–6) to brown (7E5–7); volval remnants on pileus often pyramidal to verrucose, 2–9 mm high and 2–8 mm wide, sometimes scaly, yellowish white (4A2) to dark brown (7F7–8); margin non-striate, appendiculate; context 5–17.0 mm wide, yellowish white (4A2) to light brown (7D4–5). Lamellae free, crowded, reddish brown (8E7–8) to dark brown (8F7–8); lamellulae attenuate. Stipe 23.8–27.3 cm long × 2.0–2.5 cm diam. (the length includes the basal bulb), cylindrical, light brown (7D4–6), densely covered by floccose to pulverulent white (1A1) to reddish brown (8E7–8) squamules; context solid; basal part 5.3–5.6 cm diam., globose to subglobose, upper part covered with verrucose to squarish, reddish brown (8D5–6) warts. Annulus fragile and fugacious. Odor not recorded.
Lamellar trama bilateral. Mediostratum 20–35 μm wide, consisting of abundant ellipsoid or clavate to fusiform inflated cells (56–135 × 17–35 μm); filamentous hyphae abundant, 2–6 μm wide; vascular hyphae scarce. Lateral stratum 20–30 μm wide, consisting of abundant ellipsoid to fusiform inflated cells (48–73 × 13–23 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 3–6 μm wide.
Subhymenium 25–40 μm thick, with two–three layers of subglobose, or irregular cells, 15–28 × 10–18 μm.
Basidia (
Figure 10b) 38–56 × 12–20 μm, clavate, four-spored; sterigmata up to 3–6 μm long; basal septa lacking clamps.
Basidiospores [50/2/2] (8.0–) 8.5–10.5 (–11.0) × 8.0–10.0 μm, avl × avw = 9.2 × 8.9 μm, Q = 1.00–1.13 (–1.24) μm, Qm = 1.04 ± 0.05, globose to subglobose, sometimes broadly ellipsoid, thin-walled, smooth, colorless to pale yellow, amyloid (
Figure 10a).
Lamellar edge sterile, consisting of pyriform to subglobose, or ellipsoid to clavate inflated cells (13–41 × 9–32 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae abundant, 2–6 μm wide, irregularly arranged.
Pileipellis 70–150 μm thick, two-layered, consisting of radial filamentous hyphae (3–12 μm wide); vascular hyphae scarce.
Volval remnants on pileus (
Figure 10c) consisting of vertically arranged elements: inflated cell (26–150 × 22–87 μm), abundant to predominant, subglobose to ellipsoid, single or in chains of two–three, colorless or light brownish yellow; filamentous hyphae (3–9 μm wide) abundant, colorless or light yellow; vascular hyphae scarce.
Volval remnants on stipe base predominately composed of irregularly arranged light-brownish yellow, pyriform to subglobose, or ellipsoid to fusiform inflated cells (17–72 × 13–67 μm), mixed with abundant filamentous hyphae (3–7 μm wide).
Stipe trama consisting of longitudinally arranged, long clavate terminal cells, 170–330 × 18–40 μm; filamentous hyphae abundant, 2–9 (–14) μm wide; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous or coniferous forests dominated by Dipterocarpus, Shorea, and Pinus species, respectively. Basidiomata occurs in the rainy season.
Distribution: This species is currently known in China [
69], and Thailand [this study].
Specimens examined: THAILAND, Phetchabun Province, Nam Nao District, alt. 887 m, 17 August 2020, Yuan S. Liu, STO-2020-324 (SDBR-STO20-324); Yuan S. Liu, STO-2020-338 (SDBR-STO20-338).
Notes: Our Thai materials possess very large basidiomata, pyramidal to verrucose and dark-brown pileal remnants, non-striate and appendiculate margin, solid stipe densely covered with floccose to pulverulent white to reddish-brown squamules, globose to subglobose stipe base surrounded by verrucose to squarish, reddish-brown warts. All these features are consistent with the original description of
Amanita cacaina, which was recently published in China in 2023 [
69]. Morphologically,
A. cacaina is similar to a number of taxa, e.g.,
A. pseudosculpta L.P. Tang and T. Huang,
A. sculpta, and
A. westii (Murrill) Murrill. Detailed comparisons between
A. cacaina and the related species above can be found in Huang et al. [
69].
Amanita citrinoannulata Y.Y. Cui, Q. Cai and Zhu L. Yang, Fungal Divers. 91: 186 (2018).
Figure 2l and
Figure 11.
Basidiomata is small. Pileus 2.4 cm diam., plano-convex, brownish orange (5C4–6) to yellowish brown (5E7–8); volval remnants on pileus floccose-felted, dark yellow (4C8), densely arranged over disk, often washed away by rain; margin non-striate, non-appendiculate; context white (8A1), slowly changing to pinkish white (8A2) after injury. Lamellae free, crowded, white (1A1); lamellulae attenuate. Stipe 4.2 cm long × 0.4 cm diam. (the length includes the basal bulb), subcylindrical or slightly tapering upwards, yellowish white (4A2), turning to pinkish white or pale red (8A2–3) when bruised, covered by yellowish-white (4A2) to brown (5E8), snakeskin-shaped squamules above the annulus and fibrous squamules under the annulus; context solid, slowly changing to pinkish white (8A2) after injury; basal part 0.8 cm diam., ventricose, upper part covered with irregular, floccose, yellowish-white (4A2) volval remnants. Annulus subapical, membranous, fugacious, yellowish white to pale yellow (3A2–3). Odor not recorded.
Lamellar trama bilateral. Mediostratum 20–30 μm wide, consisting of abundant ellipsoid or clavate inflated cells (40–85 × 14–28 μm); filamentous hyphae abundant, 2–6 μm wide; vascular hyphae scarce. Lateral stratum 25–40 μm wide, consisting of abundant ellipsoid to clavate or ovoid inflated cells (20–80 × 14–30 μm), diverging at an angle of about 45° to the mediostratum; filamentous hyphae abundant, 2–11 μm wide.
Subhymenium 20–25 μm thick, with two–three layers of subglobose, or irregular cells, 7–23 × 6–15 μm.
Basidia (
Figure 11b) 30–40 × 8–12 μm, clavate, four-spored; sterigmata up to 3–4 μm long; basal septa lacking clamps.
Basidiospores [51/1/1] (7.0–) 7.5–9.0 × 6.0–7.5 μm, avl × avw = 8.1 × 6.5 μm, Q = (1.07–)1.14–1.38 (–1.50) μm, Qm = 1.25 ± 0.09, subglobose to broadly ellipsoid, thin-walled, smooth, colorless to light brown, amyloid (
Figure 11a).
Lamellar edge sterile, consisting of globose to subglobose, or ellipsoid inflated cells (18–36 × 17–28 μm), single or in chains of two–three, thin-walled, colorless; filamentous hyphae abundant, 2–6 μm wide, irregularly arranged.
Pileipellis 100–150 μm thick, two-layered; upper layer (40–70 μm thick) slightly gelatinized, consisting of subradially arranged, thin-walled, colorless to pale yellow, filamentous hyphae 2–10 μm wide; lower layer (60–80 μm thick) consisting of radially and compactly arranged, colorless to pale-yellow filamentous hyphae 2–11 μm wide; vascular hyphae fairly abundant.
Volval remnants on pileus (
Figure 11c) consisting of almost vertically arranged elements: inflated cell (17–52 × 15–40 μm), abundant to predominant, subglobose to globose, single or in chains of two–three, colorless or light brown; filamentous hyphae (2–6 μm wide) scattered, colorless or light yellow; vascular hyphae scarce.
Volval remnants on stipe base similar to the remnants on pileus but with more filamentous hyphae.
Stipe trama consists of longitudinally arranged, long clavate to fusiform terminal cells, 63–238 × 20–38 μm; filamentous hyphae abundant, 2–7 μm wide; vascular hyphae scarce.
Annulus consisting of radially arranged elements: inflated cells scattered, subglobose to clavate or ellipsoid, 20–43 × 12–34 μm, colorless to light brown, thin-walled; filamentous hyphae very abundant to predominant, 2–6 μm wide, colorless, thin-walled; vascular hyphae scarce.
Clamps absent in all parts of basidioma.
Habitat: Solitary to scattered on soil in tropical deciduous forests dominated by Dipterocarpus and Shorea species. Basidiomata occurs in the rainy season.
Distribution: This species is currently known in China [
2], and Thailand [this study].
Specimens examined: THAILAND, Chiang Mai Province, Mae Taeng District, alt. 720 m, 9 August 2019, Yuan S. Liu, STO-2019-483 (SDBR-STO19-483).
Notes:
Amanita citrinoannulata was reported from China [
2]. Our Thai material has a small basidioma, brownish pileus covered with floccose-felted, with dark-yellow remnants; context of pileus changing to pinkish tone after injury; yellowish stipe always changing to pinkish white or pale red when bruised; snakeskin-shaped squamules above the annulus and fibrous squamules under the annulus. All these features are consistent with the type specimen.
Morphologically,
Amanita citrinoannulata is similar to a number of taxa, e.g.,
A. flavorubens (Berk. and Mont.) Sacc.,
A. fritillaria Sacc. f.
fritillaria, and
A. spissacea. Detailed comparisons between
A. citrinoannulata and the species mentioned above can be found in [
2,
19].
Phylogenetically,
Amanita citrinoannulata is closely related to
A. detersa Zhu L. Yang, Y.Y. Cui and Q. Cai,
A. flavoconia G. F. Atk, and
A. spissa (Fr.) P. Kumm. However,
A. detersa, reported from China [
2], has a grayish-toned pileus, yellowish volva remnants on both pileus and stipe base, and pileal context not changing color when injured.
Amanita flavoconia, reported from America [
70], possesses a pileus that is usually umbonate, the remnants on its pileus are absent or present as yellow patches or powder, and has much narrower basidiospores (6.0–9.0 × 4.0–6.0 μm) [
70].
Amanita spissa differs in having a robust basidiomata, lacking a color change in the pileal context, the snakeskin-liked squamules on the stipe being absent, and a white annulus [
2,
19].