Amanita zangii Zhu L. Yang, T.H. Li & X.L. Wu
Index Fungorm number:xxx; Face Fungorunm number: xxx
Basidiomata small to medium-sized. Pileus 50–80 mm wide, hemispherical when young, convex to broadly convex to applanate at maturity, dry, subviscid to viscid when moist, dirty white to milk white (1A2), minutely fibrillose, covered with felty to subfibrillose to flat verrucose universal veil remnants, greyish brown to dark brown, dark grey to blackish (6E2-3, 6F7). Margin non-striate, appendiculate. Context 4–7 mm thick above stem, soft to slightly hard, white (1A1). Lamellae 7–11 mm broad, free, subcrowded to crowded, white to pale cream (1A1, 4A1-3), lamellulae of 3–5 lengths, attenuate. Stipe 50–85 × 10–15 mm (length includes bulb), subcylindric, slightly tapering downwards, with irregular, sub-bulbous, rooting base, whitish to yellowish white (2A1-2), minutely farinose at apex, whitish grey (4A1) at base. Context solid, white (1A1). Bulb subclavate to subglobose, sometimes irregularly radicating, up to 30 mm wide, white to whitish gray (1A1, 4A1). Universal veil on stipe base as covering of farinose to floccose remnants, greyish white (4A1). Partial veil subapical to superior, submembranous-subfibrillose, white to whitish above (1A1), below concolorous with universal veil. Odor not recorded. Lamellar trama bilateral, divergent, mediostratum 30–55 μm wide, filamentous hyphae 4–8 μm wide, branching, hyaline, thin-walled, inflated cells terminal, ellipsoid to fusiform and 45–90 × 10–25 μm, vascular hyphae rare. Subhymenium 25–55 μm thick, 2–4 layers of subglobose, ovoid or rarely broadly ellipsoid cells, 16–22 × 8–20 μm. Basidia 32–55 × 10–12 μm, 4-spored, with sterigmata up to 4 μm long, clamps absent. Basidiospores [50/2/2] 9.4−12.0 (−12.4) × (6.5−) 6.6−8.8 (−8.9) μm, (L’ = 10.7 μm, W’ = 7.6 μm, Q = (1.23–) 1.30–1.61 (–1.71), Q’ = 1.41 ± 0.10), smooth, hyaline, colorless, thin-walled, amyloid, ellipsoid, rarely broadly ellipsoid to elongate, rarely adaxially flattened, apiculus rather variable, sublateral, proportionately small or rarely larger, cylindric to truncate-conic. Contents monoguttulate or rarely granular, white in deposit. Lamellar edge sterile, filamentous hyphae 4–8 μm wide, branching, hyaline, colorless, thin-walled, inflated cells broadly clavate, dominating, 20–32 × 13–18 μm, hyaline, colorless, thin-walled. Pileipellis 50–80 μm thick, 1-layered to hardly differentiated. Filamentous hyphae 2–7 μm wide, gelatinized, hyaline, occasionally with intracellular yellow to pale brown pigment, thin-walled. Universal veil on pileus filamentous hyphae 4–6 μm wide, frequently hyaline and colorless, occasionally with intracellular brown pigment, slightly thick-walled, with terminal subcylindric to subfusiform cells, 70–100 × 25–38 μm, with occasional elongate inflated cells, dominating subglobose to broadly ovoid cells, singly or 2-3 in chain, 16–32 × 11–17 μm. Universal veil on stipe base filamentous hyphae 2–5 μm wide, hyaline or sometimes with intracellular yellow pigment, thin-walled, inflated cells broadly clavate, ovoid or subglobose, singly or 2-3 in chain, dominating, 28–60 × 15–50 μm. Stipe trama longitudinally acrophysalidic, filamentous hyphae 1–7 μm wide, hyaline, sometime with intracellular pale yellow pigment, acrophysalides slightly clavate, 150–300 × 30–45 μm, vascular hyphae rare. Partial veil filamentous hyphae 2–5 μm wide, branching, hyaline, colorless, thin-walled, with inflated terminal segments, 12–25 μm wide, vascular hyphae not observed.
Habitat: solitary or scattered on ground in forest of Fagaceae or deciduous dipterocarps.
Specimens examined: THAILAND, Chiang Mai Province, 3 km down road from Tharn Thong Lodges Resort, Mae-on District, Huai-kaeo Subdistrict, elev. 720 m, 11 June 2013, B. Thongbai, BZ201356 (MFLU 15-0130, BBH 40578), Lampang Province, along road number 1252, elev. 1420 m, 15 June 2013, B. Thongbai, BZ201344 (MFLU 15-0144, BBH 40580).
Known distribution: China, Japan and now Thailand.
Notes: Basidiocarps of A. zangii have dark grey to blackish, felty to subfibrillose universal veil remnants on the pileus. The volval tissue is dominated by chains of elongate inflated cells. In addition, an appendiculate pileus margin is characteristic of the species. Amanita zangii is a member of Bas’ stirps Hesleri (Bas 1969) along with A. hesleri Bas (eastern North America; Bas 1969) and A. veldiei D. A. Reid & Eicker ex Redhead (South Africa; Reid & Eicker 1991, Redhead 2016, Tulloss et al. 2016). Based on the data of Wolfe et al. (2012) and evidence that the members of the stirps are mycorrhizal in contrast to those amanitas with a putative or established amycorrhizal mode of acquiring carbon [attributed to the remainder of the subsection Vittadiniae Bas (Bas 1969)], Tulloss et al. (2016) segregated stirps Hesleri from subsect. Vittadiniae. Vizzini et al. (2012) introduced the new combination Aspidella zangii based on their assumption that the present species is one of the amycorrhizal amanitas. This error was not repeated by Redhead et al. (2016). Taxa in stirps Hesleri have been repeatedly collected in forest habitats in association with members of the Fagaceae, Pinaceae and Dipterocarpaceae, which suggests they are ectomycorrhizal (Tulloss 2016b, Tulloss & Possiel 2016, Tulloss & Yang 2016c). A. hesleri, a close relative to A. zangii on morphological and genetic grounds, is clearly segregated from the supposedly amycorrhizal group in the large, four gene phylogeny of Wolfe et al. (2012). Existing data indicate that A. hesleri and A. zangii are sister taxa (Tulloss et al. 2016). Thai specimens were collected from forest dominated by Fagaceae or in deciduous dipterocarp forest. Morphological comparisons between the Thai collections and those originally described from China indicate similarity in size of basidiomata and in size and shape of basidiospores. The stipe was clearly bulbous in the holotype (Yang et al. 2001) whereas the Thai collection showed an irregular, sub-bulbous and rooting stipe base. However, in this regard, it is worth noting that the bulb of A. hesleri can take multiple forms as shown in the illustrations of Tulloss (2016b). A BLAST search on the ITS sequence of our A. zangii material indicated 100% similarity and 100% query cover with a sequence from the holotype of A. areolata (Oda et al. 2002b)―a synonym of A. zangii (Tulloss & Yang 2016c). No LSU sequence was present for A. areolata in GenBank. The combined genes phylogenetic analyses indicated that A. zangii clustered with the A. zangii sequences from GenBank; the cluster appears to be early diverging in sect. Phalloideae with 100% BS, PP = 1.0 (Figure 7). Cai et al. (2014) also showed a clade including A. zangii and A. sp. (HKAS77321) as early diverging in the Phalloideae. They explain why the putative relationship of A. zangii is odd due to highly constrasting morphologies. We agree with Cai et al. (2014) that further investigation into the matter would be useful. (from Thongbail et al. 2016)