Amanita concentrica T. Oda, C. Tanaka & Tsuda, Mycoscience

Thongbai, Benjarong, Tulloss, Rodham E., Miller, Steven L., Hyde, Kevin D., Chen, Jie, Zhao, Ruilin & Raspé, Olivier, 2016, A new species and four new records of Amanita (Amanitaceae; Basidiomycota) from Northern Thailand, Phytotaxa 286 (4), pp. 211-231 : 219-221

Amanita concentrica T. Oda, C. Tanaka & Tsuda, Mycoscience 43 (1): 81, 2002a ( Figure 3 )

Basidiomata [ Fig. 3 (a)] medium-sized. Pileus ca. 115 mm wide, hemispheric or parabolic when young, then convex to plane at maturity, dry, slightly shiny when moist, white to yellowish white (3A1-2), with pale yellow or butter yellow at center (4A2-3), covered with distinctive universal veil remnants as pyramidal warts up to 4 mm high, crowded over disc, becoming floccose patches toward margin, whitish to light orange, grayish orange to brownish orange (4C3-5A3); margin slightly striate, not appendiculate with universal veil, sometimes appendicculate with fragments of partial veil; context 4–9 mm thick above stem, soft to slightly hard, white to orange white (5A1-2). Lamellae 4–8 mm broad, free, crowded, white to yellowish white (3A1-2); lamellulae of 3–6 lengths, truncate to subtruncate. Stipe 95–125 × 1.5–2.3 mm (length includes bulb), tapering upwards, white to pale yellow (1A2-3A1-3), squamulose to scaly, light yellow (3A1-2) at apex, decorated with grayish orange to brownish orange (6B3-6D4) scales at base; context stuffed to hollow, white to yellowish white (1A1-3A1-2). Bulb subclavate to subnapiform, marginate, up to 35 mm wide, white to yellowish white (3A1-2). Universal veil on stipe base 3–5 concentric rings of whitish, grayish yellow to brownish orange (6B3-6D4) scales on the upper part of the bulb. Partial veil subapical, membranous, white to yellowish white (1A2-3A1-2). Odor not recorded.

Lamellar trama bilateral, divergent; mediostratum 40–60 μm wide, filamentous hyphae 2–8 μm wide, frequently branching, hyaline, colorless, with terminal cell slightly clavate to subfusiform, 45–130 × 10–25 μm, thin-walled; vascular hyphae rare. Subhymenium [ Fig. 3 (k)] 20–45 μm thick; filamentous hyphae 4–15 μm wide, with some intercalary inflated elements; inflated cells dominating, in 2–3 layers, broadly ellipsoid to ellipsoid to occasionally subfusiform, 9–26 × 8–22 μm. Basidia [ Fig. 3 (k–m)] 43–55 × 6–14 μm, clavate, 4- or (occasionally) 2-spored, with sterigmata up to 6 μm long; clamps present. Basidiospores [ Fig. 3 (b–j)] [50/1/1] 7.4–9.7 (–11.4) × (5.7–) 6.5–8.4 (–8.8) μm, (L’ = 8.5 μm; W’ = 7.4 μm; Q = (1.02–) 1.05–1.30 (–1.56); Q’ = 1.16 ± 0.11), smooth, hyaline, colorless, thin-walled, inamyloid, subglobose to broadly ellipsoid, occasionally globose or ellipsoid, occasionally adaxially flattened; apiculus rather variable, sublateral, prominent, cylindric to truncate-conic; contents monoguttulate; white in deposit. Lamellar edge sterile; filamentous hyphae 3–8 μm wide, hyaline, colorless, thin-walled, with slightly inflated segments; inflated cells dominating ovoid to subglobose to ellipsoid, and occasionally broadly clavate, 18–40 × 8–22 μm, hyaline or occasionally with intracellular pale brown pigment. Pileipellis 150–420 μm thick, 2-layered; upper layer 70–220 μm thick, filamentous hyphae 3–5 μm wide, strongly gelatinized, branching, hyaline, colorless, thin-walled; lower layer about 80–200 μm thick, filamentous hyphae 2–4 μm wide, branching, hyaline, thin-walled. Universal veil on pileus filamentous hyphae 4–7 μm wide, branching, hyaline, colorless or occasionally with intracellular pale brown pigment, thin-walled; inflated cells ovoid to ellipsoid dominating, 20–62 × 10–38 μm; vascular hyphae not observed. Universal veil on stipe base filamentous hyphae 2–7 μm wide dominating, hyaline, colorless or occasionally with intracellular pale brown pigment; ovoid to ellipsoid cells, 30–62 × 15–32 μm; vascular hyphae not observed. Stipe trama longitudinally acrophysalidic; filamentous hyphae 2–9 μm wide; acrophysalides clavate to pyriform, 120– 210 × 25–45 μm; vascular hyphae not observed. Partial veil filamentous hyphae 2–5 μm wide, branching, hyaline, colorless.

Habitat: scattered on the ground in forest of Fagaceae .

Specimens examined: THAILAND, Lampang Province, along the road number 1252, 18.935, 99.390833, elev. 1,450 m, 5 July 2013, O. Raspé & B. Thongbai BZ201326 (MFLU 15-0128, BBH 40576).

Known distribution: This species was originally described from Japan. It has also been found in China, Nepal, northern India ( Tulloss & Yang 2016h) and now Thailand.

Remarks: Amanita concentrica belongs to Amanita [sect. Amanita , series Amanita ] stirps Concentrica ( Tulloss & Yang 2016a) . In the field, outstanding morphological characteristics of A. concentrica are the whitish to brownish orange, grayish orange to orange pyramidal warts on a white to pale-yellowish pileus. The presence of these prominent, pointed warts and concentric rows of warts on the upper bulb can lead to taxonomic confusion with members of Amantia [sect. Lepidella ] subsect. Solitariae (e.g., A. eijii Zhu L. Yang [2002] ). However, the inamyloid basidiospores clearly place A. concentrica into subgenus Amanita , for which there is genetic support. The size of basidiomata as well as the size and shape of basidiospores of the Thai collection is very similar to the original description from Japan ( Oda et al. 2002a, 2002c). The holotype was reported from an area with elevation of 300 m, in an evergreen broad-leaved forest with Castanopsis cuspidata (Thunb. ex Murray) Schottky var. sieboldii (Makino) Nakai and Quercus glauca Thunb. The Thai specimen was collected at an elevation of 1,450 m in a fagaceous forest with, e.g., Castanopsis spp. No LSU sequences from the holotype of A. concentrica have been accessioned in GenBank.

The orangish or rusty stains on the basidiomata collected in Thailand are reminiscent of similar stains on normally white amanitas that Tulloss has seen in Costa Rica and (more rarely) in North America. It is likely that the phenomenon is superficial and can be moved by water. (See the vertical streaks on the stems in Fig. 3 .) This suggests that the phenomenon is not genetically determined by the amanita, but is due to some other organism’s presence on the mushroom. The study of the surface ecology of amanitas is largely unpursued except for, to some degree, in the cases of Hypomyces hyalinus (Schwein.) Tul. & Tul. and Mycogone rosea Link. There are other phenomena that appear to be related to organisms “infecting” amanitas that have been the cause of naming “infected” mushrooms as new or provisional taxa—sometimes mistakenly—for example, the “yellowing syndrome” [ A. crassifolia Bas nom. prov. ( Bas 1969, Tulloss 2016d) and other taxa]; the “cheese odor syndrome” [ A. alexandri Guzmán ( Guzmán 1975, 1980; Morales-Torres et al. 1999; Tulloss 2016c)]; and blackening of the volva and adjacent tissues [ A. muscaria var. fuligineoverrucosa Neville & Poumarat ( Neville & Poumarat 2002, 2004; Tulloss 2005, 2016e) and A. brunneolocularis Tulloss, Ovrebo & Halling ( Tulloss et al. 1992, 2016f)].

Figures

FIGURE 3. Basidiomata of Amanita concentrica. a young and mature basidiomata. b–d basidiospores in 5% KOH. e–g basidiospores in congo red. h–j basidiospores in Melzer’s reagent. k–m basidia and subhymenium at different stages of development; showing clamps at the bases of basidia. (a–m: BZ201326) (scale bars: a = 5 cm. b–j = 5 μm, k = 20 μm, l–m = 10 μm).