Phlebopus portentosus (Berk. & Broome) Boedijn, Sydowia, 1951

Xie, Hui-Jing, Zhang, Chun-Xia, He, Ming-Xia, Liang, Zhi-Qun, Deng, Xiao-Hua & Zeng, Nian- Kai, 2021, Buchwaldoboletus xylophilus and Phlebopus portentosus, two non-ectomycorrhizal boletes from tropical China, Phytotaxa 520 (2), pp. 137-154 : 147-149

Phlebopus portentosus (Berk. & Broome) Boedijn, Sydowia 5(3–6): 218, 1951 ( Figs. 4 , 6 )

Description:— Basidiomata medium to very large. Pileus up to 18 cm diam, subhemispherical, convex, plano-convex to applanate; margin decurved, sometimes revolute when old; surface dry, nearly glabrous, yellowish brown (3B6), brown (4C7) to dark brown (4C8); context about 2 cm thick in the center of the pileus, light yellow, sometimes bluing when injured. Hymenophore poroid, depressed around apex of stipe; pores yellow (3A6), almost to round, yellowish brown (3B6), about 0.3 mm diam, unchanging in color when injured; tubes 1–1.5 cm in length, yellow (2A6), unchanging in color when injured. Stipe 8–10.5 × 2.5–4 cm, central, subcylindrical or subclavate, solid, base slightly enlarged; surface dry, nearly glabrous, brown (4C8) to brownish black (4E8); context light yellow (1A5), unchanging in color when injured; annulus absent; basal mycelium yellow (1A6). Odor indistinct.

Basidia 18–30 × 10–14 μm, clavate, thin-walled, 4-spored, colorless in KOH, yellow in Melzer’s reagent; sterigmata 4–5 μm long. Basidiospores [60/3/3] 6–9(–10) × (4.5–)5–7(–8) μm, Q = (1–)1.1–1.4(–1.5), Qm = 1.26 ± 0.11, broadly ellipsoid, slightly thick-walled (up to 0.5 μm), yellowish brown in KOH, yellowish brown in Melzer’s reagent, smooth. Hymenophoral trama composed of thin- to slightly thick-walled (up to 0.8 μm) hyphae, 3–10 μm wide, colorless to light yellow in KOH, yellow to brownish yellow in Melzer’s reagent. Cheilocystidia 13–27 × 4–10 μm, pyriform, subfusiform or fusiform, thin-walled, colorless to light yellow in KOH, yellow to brownish yellow in Melzer’s reagent. Pleurocystidia 15–28 × 7–13 μm, pyriform, subfusiform or fusiform, thin-walled, colorless to light yellow in KOH, yellow to brownish yellow in Melzer’s reagent. Pileipellis a trichoderm 130–200 μm wide, composed of thin- to slightly thick-walled (up to 1 μm) hyphae, light yellow in KOH, yellow to brownish yellow in Melzer’s reagent, 3–9 μm in width; terminal cell 15–36 × 3–8 μm, clavate or subcylindrical, subfusiform or fusiform, with obtuse apex. Pileal trama made up of hyphae 3–14 μm in diam, slightly thick-walled (1 μm), colorless to light yellow in KOH, yellow, yellowish brown, reddish brown in Melzer’s reagent. Stipitipellis a trichoderm-like structure 90–150 μm wide, composed of thin- to slightly thick-walled (up to 0.5 μm), 3–6 μm wide, light yellow in KOH, yellow to brownish yellow in Melzer’s reagent, emergent hyphae with subfusiform, fusiform or clavate terminal cells (15–31 × 3–6 μm). Stipe trama composed of cylindrical, colorless to light yellow in KOH, yellow, yellowish brown, reddish brown, slightly thick-walled (up to 1 μm), parallel hyphae 3–14 μm wide. Clamp connections present in all tissues.

Habitat:—Solitary or scattered under Eucalyptus tereticornis Smith or Ficus microcarpa L. f.

Known distribution:—Southwestern and southern China; Sri Lanka ( Pegler 1986), Thailand ( Sanmee et al. 2003).

Specimens examined:— CHINA. Hainan Province: Haikou City, Jinniuling Park , elev. 20 m, 22 May 2008, N. K . Zeng 22 ( FHMU1 ); Wanning City, Xinglong Tropical Oark , elev. 115 m, 25 May 2013, N. K . Zeng 1186 ( FHMU753 ); same location, 7 July 2013, N. K . Zeng 1248 ( FHMU806 ); Haikou City , beside the roadway, elev. 15 m, 13 August 2019, N. K . Zeng 5041 ( FHMU5934 ). Yunnan Province: Kunming City , bought in the market, 16 August 2016, N. K . Zeng 2779 ( FHMU1768 ); Jinghong City , artificial cultivation, 4 February 2021, C . X. Zhang s.n. ( FHMU5936 , 5937 , 5938 ) .

Notes:—Our specimens identified as P. portentosus are well characterized by a large fruitbody with a yellowish brown, brown, dark brown pileus, a brown, brownish black stipe, a light yellow context sometimes bluing when injured, broadly ellipsoid basidiospores, terminal cells of pileipellis mostly subfusiform or fusiform, and a distribution in tropical Asia. The morphological features of the Chinese collections match well with those of P. portentosus from Sri Lanka ( Pegler 1986), except that the cystidia were not observed by Pegler (1986) whereas they are common in the Chinese specimens ( Fig. 6c, d ).

Morphologically, P. portentosus is very similar to P. roseus , a species originally described from Sichuang Province of southwestern China. However, P. roseus has a rose pink to reddish stipe, tubular hymenophore with nested angular pores of multiple sizes, and a distribution in subtropical China ( Mei et al. 2020).

Figures

FIGURE 4. Basidiomata of Phlebopus portentosus. (a from FHMU5934; b, c, f from FHMU753; e, g from FHMU1768; d from FHMU5936. a–c, e, f photos by N.K. Zeng; d photo by X.J. Xu.

FIGURE 6. Microscopicfeatures of Phlebopus portentosus(FHMU5934).a.Basidia.b. Basidiospores.c. Cheilocystidia.d.Pleurocystidia. e. Pileipellis. f. Stipitipellis. Bars = 10 μm. Drawings by H.J. Xie.