Inocybe hopeae Raghoonundon & Raspé, 2023

Raghoonundon, Bhavesh, Vadthanarat, Santhiti, Hu, Yuwei & Raspé, Olivier, 2023, Inocybe hopeae sp. nov. and first record of Pseudosperma keralense (Inocybaceae) from Thailand, European Journal of Taxonomy 870, pp. 30-45 : 34-39

Inocybe hopeae Raghoonundon & Raspé sp. nov. MycoBank: MB844101

Figs 2–4

Diagnosis

Inocybe hopeae sp. nov. is distinguished from Inocybe thailandica by having wider brownish orange to brown pileus darker towards the margin, thicker off-white to pale brown context, light brown to dark brown stipe, pleurocystidia being different from cheilocystidia, broader and longer basidia and caulocystidia.

Etymology

The epithet ʻ hopeae ʼ refers to being found under the tree Hopea odorata Roxb.

Material examined

Holotype THAILAND • Chiang Rai Province, Mueang district, Mae Fah Luang University ; 20°02′54″ N, 99°53′30″ E; 427 m a.s.l.; 30 Jun. 2020; O. Raspé, OR 1665; GenBank accessions: LSU ON831503, tef 1 ON553695, rpb 2 ON553692; MFLU[MFLU22-0084].

Additional material

THAILAND • Chiang Rai province, Mueang district, Mae Fah Luang University ; 20°02′47″ N, 99°53′41″ E; 442 m a.s.l., 20 Apr. 2021; B. Raghoonundon, BR244; MFLU[MFLU22-0082] • Chiang Rai Province, Pa daet; 19°34′15″ N, 100°00′23″ E; 603 m a.s.l., 6 Sep.2019; O. Raspé, OR1630; MFLU[MFLU22-0085] • same collection data as for preceding; O. Raspé OR1632; MFLU[MFLU23-0076] .

Description

Pileus 11–51 mm in diameter, at first obtusely conical, becoming umbonate to plano-umbonate when mature, margin deflexed; surface dull and dry, fibrillose to striate with recurved scales, brownish orange (5C4–5C7) to brown (6D5–6E6), dark brown (6F6–7F6) near the margin; thin context 2–4 mm, off-white to pale brown (6A1–6C4), unchanging when bruised, solid and fleshy. Stipe central, cylindrical, 33–94 mm × 2–7 mm, slightly bulbous; surface even, dull and dry, with minute squamules at the top, elsewhere glabrous, light brown (6D4–7D5) to dark brown (7F5), darker towards the top, unchanging when bruised; basal mycelium off-white (6A1), turning orange when bruised (6A7–6A8); context solid or fibrillose, fleshy, pale brown (6C4), staining slightly orange (5A3–5A4) when bruised. Hymenophore lamellate, adnexed to adnate with a decurrent tooth; lamellae 35–54 reaching stipe, 5–7 lamellulae, close, thick, ventricose, forked mostly near the margin, yellowish gray (4B1–4B2), becoming brown (5D5–6E5) with age, lamellae edge even. Smell and taste not distinctive.

Basidiospores [125/6/4] (5.3–)5.8–8.2–11.1(–14) µm in diam., globose to ovoid, with conical-spinose projections up to 3.9 µm long, sub–globose to globose, brownish in KOH and NH 4 OH. Basidia (33.2–)33.9–44–51.9(–52.3) × (9.8–)10.1–14.6–17.6(–17.7) µm, 4-spored, clavate, hyaline, sterigmata up to 8 µm long. Cheilocystidia (39–)39.5–47.3–71(–71) × (10.2–)10.2–14.9–20.2(–20.2) µm, frequent, thick-walled, fusiform to broadly fusiform with some scattered crystals at the top, hyaline, yellowish in KOH and NH 4 OH. Pleurocystidia (27.6–)29.1–41.9–50.1(–54.7) × (9.2–)9.4–12.9–15.2(–16.5) µm, fusiform, thick-walled, hyaline, yellowish in KOH and NH 4 OH. Pileipellis an intricate trichoderm of interwoven cylindrical hyphae 4–6.2–8 µm wide, terminal cells conical to fusiform, wall encrusted with yellowish brown pigments; subpellis hyphae 11–14.5–22 µm wide, broadly cylindrical, encrusted with yellowish brown pigments. Caulocystidia (32–)34–44.9–57.8(–58.1) × (13.7–)14.5–18.5–21.4(–23.2) µm, polymorphic, clavate to fusiform, thick-walled, hyaline, yellowish in KOH and NH 4 OH, rarely with crystals. Stipitipellis a trichoderm of interwoven hyphae 3–4.9–8 µm wide, partially composed of clavate cells, slightly brownish in KOH. Clamp connections present.

Habitat

Scattered on soil under Hopea odorata ; in tropical forest dominated by Dipterocarpaceae Blume ( Dipterocarpus spp. and Shorea spp. ), with some Fagaceae Dumort. ( Quercus spp. , Lithocarpus spp. and Castanopsis calathiformis Rehder & E.H.Wilson ). Also found under planted Hopea odorata .

Known distribution

Thus far known only from northern Thailand.

Notes

Inocybe hopeae sp. nov. is macro-morphologically characterized by medium sized basidiomes, brownish orange to brown pileus becoming darker towards the margin, off-white to pale brown context, light brown to dark brown stipe with off-white basal mycelium and pale brown to grayish brown lamellae. Molecular data ( Fig. 1 ) confirmed a close relationship between I. hopeae and another species from Thailand, I. thailandica . However, when compared to the latter, our species is morphologically different. Inocybe thailandica has a dark brown pileus becoming pale brown towards the margin, which is the opposite of I. hopeae , in which the brownish orange pileus is darker towards the margin. Moreover, I. hopeae has a wider pileus and thicker context as compared to I. thailandica . Finally, I. thailandica has a light brown stipe that is darker towards the base, whereas in I. hopeae , the stipe is darker brown towards the apex.

The micro-morphological characters of I. hopeae sp. nov. somewhat resemble those of I. thailandica . However, upon closer examination, I. hopeae have broader and longer basidia (33.2–52.3 × 9.8–17.7 µm) compared to I. thailandica (28–36 × 7–9 µm). The caulocystidia of I. hopeae (32–58.1 × 13.7–23.2 µm) also are longer and broader than those of I. thailandica (20–36 × 6–12 µm). Furthermore, the cheilocystidia of I. thailandica (30–40 × 10–20 µm) are shorter than those in the new species (39–71 × 10.2–20.2 µm). Additionally, Horak et al. (2015) mentioned the pleurocystidia and cheilocystidia of I. thailandica are similar, which is not the case in I. hopeae , whereby the pleurocystidia are narrower and shorter than the cheilocystidia. The basidiomes of I. thailandica are also putative associates of Castanopsis (D.Don) Spach (Horak et al. 2015) as compared to I. hopeae , which was found in forests dominated by Dipterocarpaceae with some Fagaceae or growing in association with planted Hopea odorata .

Figures

Fig. 2. a. Basidiomes of Inocybe hopeae Raghoonundon & Raspé sp. nov. (OR1665, holotype). c–d. Basidiomes of Inocybe hopeae (OR1630). b, e–f. Basidiomes of Pseudosperma keralense (K.P.D.Latha & Manim.) Matheny & Esteve-Rav. (OR1629). Scale bars: a = 10 mm, b–d = 5 mm.

Fig. 3. Microscopic features of Inocybe hopeae Raghoonundon & Raspé sp. nov. a. Caulocystidia. b. Pleurocystidia. c. Cheilocystidia. d. Basidia. e. Pileipellis. f. Basidiospores. Scale bars: a–e = 20 µm, f = 10 µm.

Fig. 4. Scanning electron micrograph of basidiospores from the holotype of Inocybe hopeae Raghoonundon & Raspé sp. nov. (OR1665). Scale bar = 10 µm.

Fig. 1. Maximum likelihood phylogenetic tree inferred from the three gene dataset (tef1, LSU, rpb2). Seven species of Pseudosperma Matheny & Esteve-Rav. and one species of Nothocybe Matheny & K.P.D.Latha were used as outgroup taxa. Maximum likelihood bootstrap (MLB, left) ≥70% and Bayesian posterior probabilities (BPP, right) ≥ 0.95 are shown above supported branches. The new species and new record are in bold.