Hohenbuehelia lageniformis Phonemany & Raspé
Faces of fungi number: FoF 10709, MycoBank: MB 843985
Pileus 25–30 × 15–25 mm, sapathuliform when young, rounded flabelliform to sub-rounded flabelliform when mature, light yellow (4A4), pale orange to orange white (5A2–5A3), greyish orange (5B4) becoming darker with age, sometimes sessile, or with laterally attached stipe; surface moist, shiny, velutinous with whitish (1A1) hairs near the point of attachment, elsewhere light yellow to pale greyish yellow (4A4–4B4); margin discolorous from pileus, velutinous with whitish hairs as observed under the lens, incurved even when mature, entire or sometimes undulate when old. Lamellae 1–2 mm broad, decurrent, white to pale orange (5A1–5A2) becoming slightly dark with age, close to moderately crowded, in 2–3 tiers. Stipe absent or sometimes with pseudostipe 0.5–1 mm long when young and disappearing when mature. Context consisting of two layers: 1) non-gelatinous layer, 1 mm thick, fleshy, white (1A1); 2) gelatinous layer, 1–2 mm thick, soft, sticky, brownish orange to light brown (5C5–5D5). Order mild. Taste none. Spore print white. Basidiospores [150/3/3] (6.9–)7–8.8–10(–10.5) × (5.5–)6–7.0–8(–8.3) µm Q = (0.99–)1.11–1.26–1.49(–1.53) subglobose to ellipsoid in front view, ellipsoid to phaseoliform in side view, smooth, thin-walled, inamyloid. Basidia (24.3–)24–31.9–53(–58.2) × (5.4–)5.5–9.4–14(–14.6) µm, clavate, with (2)–4 sterigmata, 4–8 µm long, hyaline, smooth, thin-walled. Cheilocystidia (17.6–)18–21.9–26.5(–26.9) × (3.2–)3–5.0–9(–8.9) µm, lageniform with an inflated base with a thin, rostrate apex, hyaline, thin-walled. Pleurocystidia (31–)31–50.3–70(–71) × (9.7–)10–15.3–20(–20.3) µm, metuloidal, setiform, narrowly fusiform to fusiform, encrusted with crystals, brownish or yellowish in water, colorless but still encrusted with crystals in KOH. Hymenophoral trama subregular, hyphae 2–4 µm wide. Pileipellis an intricate trichoderm with cylindrical terminal elements 2–5 × 41–122 µm. Pileoleptocystidia absent. Pileus trama consisting of two layers: 1) upper layer gelatinous, composed horizontally arranged, smooth, colorless, encrusted hyphae, 1–4 µm wide; 2) non-gelatinous layer, composed interwoven, smooth with hyaline hyphae, 2–5 µm wide. Clamp connections present in pileipellis, pileus trama, and hymenophoral trama.
Habitat and distribution: Solitary, gregarious to imbricate, on decaying branches in a tropical forest in northern Thailand.
Additional specimens examined: Thailand. Chiang Rai Province, Muang Chiang
Rai District, Mae Yao Subdistrict, Huai Mae Sai Village, 10 July 2019, Monthien Phonemany (MFLU22-0011); ibid., 10 July 2019, Monthien Phonemany (MFLU22-
0012); ibid., 10 July 2019, Monthien Phonemany (MFLU22-0013); Pa Daed District, Pa Ngae Village, 7 September 2019, Monthien Phonemany (MFLU22-0014).
Notes: Hohenbuehelia lageniformis is characterised by velutinous pileus with whitish hairs near the point of attachment and at the margin, elsewhere pale greyish-yellow and with only sparse white hairs, subglobose to ellipsoid basidiospores, and the absence of pileoleptocystidia. Hohenbuehelia angustata, H. bonii, H. carlothornii, H. concentrica, H. flabelliformis, H. horrida, H. luteola, H. mellea Corner, and H. odorata have similar pileus colour, for example, pale orange to orange white, light yellow, yellowish-white, yellow-brown, honey-yellow or ochraceous brownish. However, those species have significant morphological differences. Hohenbuehelia angustata differs from H. lageniformis by having a smooth pileus surface, serrate margin, smaller basidiospores (3.5–5 × 2.5–3.5 μm), cutis pileipellis (Silva-Filho and Cortez 2017). Hohenbuehelia bonii differs by having a smooth pileus surface and larger pleurocystidia (56–103 × 11–19 μm) (Ainsworth et al. 2016). Hohenbuehelia carlothornii differs by having finely white-tomentose pileus, smaller basidiospores (7–8.2 × 3.1–3.7 μm), smaller basidia (19–24 × 5.2–6.8 μm), smaller cheilocystidia (13–17 × 4.9–9.4 μm), and larger pleurocystidia (55–63 × 14–18 μm) (Consiglio et al. 2018b). Hohenbuehelia concentrica has larger basidiomata (80 mm wide), ovoid basidiospores (8–8.5 × 6–6.7 μm), and no cheilocystidia (Corner 1994). Hohenbuehelia horrida has pale grey to greyish-brown lamellae, larger basidiomata (70 mm wide), smaller basidiospores (5–6 × 3–4 μm), smaller basidia (18–25 × 3–4 μm), and larger pleurocystidia (140 × 12.5 μm) (Corner 1994). Hohenbuehelia luteola differs by smaller basidiospores (8–9 × 4.5–5 μm), and smaller pleurocystidia (45–50 ×15–20 μm) (Stevenson 1964). Hohenbuehelia mellea has smaller basidiospores (5–6.5 × 2–3.5 μm), larger cheilocystidia (30–50 × 8–18 μm), and larger pleurocystidia (50–160 × 12–20 μm) (Corner 1994). Hohenbuehelia flabelliformis has thinner gelatinous layer (0.5 mm), smaller basidiospores (6–8 × 4–5 μm), smaller pleurocystidia (34–54 × 8.5–14 μm), and no cheilocystidia. Hohenbuehelia odorata differs by having smaller basidiospores (5.2–7.6 × 4.8–6.4 μm), smaller cheilocystidia (15–23.5 × 3–7 μm), smaller pleurocystidia (28.5–49 × 10–14.5 μm), and presence of cylindrical to flexuous pileoleptocystidia (Bijeesh et al. 2019). In the phylogenic tree, the most closely-related species to H. lageniformis was H. odorata (voucher TBGT17443). However, the genetic distance between the ITS sequence of H. lageniformis and H. odorata was 4.62% (27/584), which supports the distinction of the two species. Moreover, these two species also show morphological differences.
Fig. 1 Phylogeny of selected sequences of Hohenbuehelia based on a maximum likelihood analysis of three nuclear gene regions (nrITS, nrLSU, tef1). The Maximum likelihood bootstrap values (BS ≥ 70%) and Bayesian posterior probabilities values (PP ≥ 0.90) are shown on the branches. Newly sequenced collections are in bold. Five Pleurotus species were used as outgroup. (T) designates holotypes. The sequence H. flabelliformis voucher number MFLU22-0008 was identical to MFLU22-0009 (ITS only). Sequences of H. lageniformis voucher number MFLU22-0010 were identical to MFLU22-0012 (ITS and LSU). Sequences of H. tristis subsp. macrocarpa voucher number MFLU22-0016 were identical to MFLU22-0015 (ITS and LSU) and to the two specimens MFLUCC 12-0451 and HFJAU0029 identified as H. grisea (both only ITS) from GenBank, except for three substitution heteromorphisms in the ITS sequence of MFLU22-0016.