Gerronema kuruvense K. P. D. Latha & Manim. Phytotaxa 364 (1): 82–85 (2018).
Index Fungorum number: IF 824927; MycoBank number: MB 824927; Facesoffungi number: FoF 10688; Figs. 1b, 2
Pileus 27 mm diam., convex with depress center, appressed-fibrillose, pale yellow (3A3); Lamellar subdecurrent, distant (16) with 2–3 series of lamellulae, narrow, light yellow (3A5) up to 2 mm.; Stipe 25×1 mm, central, cylindrical, pubescent, slightly broadened at base, hollow, yellowish white (3A2) overall. Context thin, Odor and taste not distinctive.
Basidiospore 8–10(–11) × 4–5 (–6) μm [x=9.08±0.81×4.88±0.43, Q=1.6–2.25, q=1.89±0.25, n=25, s=1] ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia 22–36 × 7–8 μm, clavate, with 2 sterigmata, sometime with 3–4 sterigmata, thin-walled, inamyloid. Cheilocystidia scattered, 21–51× 5–11 µm, clavate, flexuose, irregular in shape, sometimes 2-celled, hyaline, inamyloid, thin-walled. Pleurocystidia absent. Lamellar trama interwoven, arranged in two directions, hyphae 3–14 µm diam., cylindrical, smooth, hyaline, inamyloid, thin-walled. Pileipellis cutis with scattered ascending pileocystidia, 4–14 µm, cylindrical, hyaline in KOH, inamyloid, thin-walled. Pileus trama sarcodimitic, subregular to interwoven, composed of 2 type of hyphae: (a) sarco-hyphae, elongate fusoid cell 94–212×10–14 µm, hyaline, smooth, inamyloid, thin-walled; (b) generative hyphae 3–7 µm wide, cylindrical, branched, hyaline, smooth, inamyloid, thin-walled. Stipitipellis cutis, hyphae 3–8 µm diam., parallel, cylindrical, hyaline in KOH, smooth, inamyloid, slightly thick-walled (up to 0.5 µm). Stipe trama sarcodimitic, parallel, composed 2 type of hyphae: a) sarco-hyphae, elongate fusoid cell 80–230(– over 250)×8–15 µm, hyaline, smooth, inamyloid, thick-walled (1–2 µm); b) generative hyphae 3–6 µm wide, cylindrical, branched, hyaline, smooth, inamyloid, thin-walled. Caulocystidia abundant, 28–47×7–9 µm, cylindrical to clavate, irregular in shape, flexuose, hyaline in KOH, inamyloid, slightly thick-walled (up to 0.5 µm). Clamp connections present in all tissues.
Habit, habitat and known distribution – Solitary on decayed wood, known from topical India and Thailand.
Material examined – Thailand, Sukhothai Province, Si Satchanalai National Park, trial to Tad Duan waterfall, 30 Aug 2020, collector N Wannathes, N Suwannarach J Kumla, S Khuna, W Phonrob, S Tabtan, BKF10266.
GenBank numbers – BKF10266-MZ452090 (ITS), MZ452669(LSU).
Notes – Gerronema kuruvense is characterized by a medium-sized omphaliod basidiomata that is convex with a depressed center. It has a pale-yellow pileus that is subdecurrent, distant, with light yellow lamella, cylindrical, central, yellowish white stipe, ellipsoid basidiospores with mean dimensions of 9.1×4.9 µm. The pileipellis is composed of hyaline with pileocystidia, non-incrusted hyphae, the presence of irregular cylindrical cualocystidia and seldomly present cheilocystidia and sarcodimitic trama tissue. The Thai specimen is almost indistinguishable from Gerronema kuruvense, which was originally described from topical India. The holotype forms a smaller size basidiomata (pilei 4–11 mm wide and stipe 3–18 mm long) and lacks cheilocystidia (Latha et al. 2018). Gerronema kuruvense is morphologically similar to G. strombodes (Berk. & Mont.) Singer, but differs by forming larger basidiomata (pilei 25–80 mm wide and stipe of 30–60 ×2–6.8 mm) greyish white pileus, pileipellis lacking pileocystidia and a complete lack of caulocystidia (Singer 1970).
Figure 1 – Basidiomata and habit. a Gerronema atrovirens (holotype: BKF10264), b G. kuruvense (BKF10266), c G. flavum (holotype: BKF10253), Scale bars=10 mm. Photographs by N. Wannathes
Figure 2 – Gerronema kuruvense (BKF10266), a Basidiomata, b Basidiospores, c Basidium, d Cheilocystidia, e Caulocystidia f Pileipellis cell. Scale bars: a=20 mm, b–e=10 μm, f=20 μm. Drawing by W. Phonrob