Geastrum villopannosum T. Wang, Q. Na & Y. P. Ge sp. nov.

Figs 5, 6, 7

Diagnosis.

Mycelial layer felted villus, encrusted with debris; pseudoparenchymatous layer lacking a collar; endoperidial body sessile without an apophysis; and peristome distinctly delimited. Differs from G. rubropusillum J. O. Sousa, Accioly, M. P. Martín & Baseia by larger expanded basidiomata and smaller basidiospores.

Holotype.

China • Heilongjiang Province, Mudanjiang City, Mudanfeng National Forest Park, 24 August 2024, leg. Tian Wang, Yupeng Ge, Qin Na, Zengcai Liu, Ruipeng Liu, Pengyu Du, and Ying Yu, 367 m asl, FFAAS 3411 (collection no. NJ 6699).

Etymology.

From Latin villus (hairy) and pannosus (felted), referring to the felted villose exoperidium.

Description.

Expanded basidiomata 26–38 mm in diameter, shallowly saccate. Exoperidium splitting into 6–8 lobes, lobes 8–11 mm wide, gradually narrowing towards the apex, acuminate or acute at the lobe apices, revolute outward under the exoperidial disc, non-hygroscopic, thin and brittle when dry. Pseudoparenchymatous layer Pallid Mouse Gray (LI 15 ’’’’’ f), Pallid Quaker Drab (LI 1 ’’’’’ f) to Pale Olive-Buff (XL 21 ’’’ f), smooth, persistent, lacking a collar. Fibrous layer Pallid Quaker Drab (LI 1 ’’’’’ f) to Pale Olive-Buff (XL 21 ’’’ f), firmly attached to pseudoparenchymatous layer. Mycelial layer Pale Olive-Buff (XL 21 ’’’ f) to * Olive-Buff (XL 21 ’’’ d), finely felted villus, encrusted with debris. Endoperidial body 12–21 mm in diameter, globose to subglobose, sessile, without an apophysis. Endoperidium Light Mineral Gray (XLVII 25 ’’’’ f), Mineral Gray (XLVII 25 ’’’’ d) to Tea Gray (XLVII 25 ’’’’ b), smooth. Peristome shortly and broadly conical, fibrillose, * Olive-Gray (LI 23 ’’’’’ b) to Deep Grayish Olive (XLVI 21 ’’’’ i), darker than the endoperidium, distinctly delimited.

Basidiospores [75 / 3 / 2] 2.6– 2.7 – 2.9 (3.1) × 2.6– 2.7 – 2.9 μm, [Q = 1.00–1.02 (1.06), Qm = 1.01 ± 0.01] [holotype (50 / 2 / 1) 2.6– 2.7 – 2.9 × 2.6– 2.7 – 2.9 μm, Q = 1.00–1.02, Qm = 1.01 ± 0.01], globose to subglobose, yellowish brown to dark brown in 5 % KOH aqueous solution, with regularly columnar ornamentation, 0.3–0.5 μm in length (under oil). Capillitial hyphae 4.1–11.7 μm in diameter, apically attenuated, unbranched, yellowish brown to dark brown, mostly hyaline, with sparse debris, very few granular protuberances, thick-walled (0.4–0.7 μm). Pseudoparenchymatous layer made up of 16–50 × 15–38 μm cells, ellipsoid, oblong or angular, pale yellowish, hyaline, thick – walled (0.5–0.7 μm). Fibrous layer composed of hyphae measuring 4.9–9.3 μm in diameter, pale yellowish to yellowish brown, hyaline, thick-walled (0.5–0.7 μm). Mycelial layer made up of hyphae measuring 4.1–6.5 μm in diameter, yellowish brown to dark brown, thick-walled (0.5–0.8 μm), with occasionally observed clamps.

Habit and habitat.

Scattered on the ground or humus layer in secondary Quercus mongolica Fisch. ex Ledeb. Forest, mainly under trees of Quercus, Syringa, Fraxinus, Betula, and Tilia.

Known distribution.

Heilongjiang Province, China.

Additional specimens examined.

China • Heilongjiang Province, Hegang City, Luobei County, Taipinggou National Nature Reserve, 29 August 2023, leg. Tian Wang, Yupeng Ge, Qin Na, Renxiu Wei, Menghui Han, Yawei Li, Xinyu Tong, and Jiang Bian, 633 m asl, FFAAS 3412 (collection no. GN 2317, Paratype).

Notes.

Geastrum villopannosum was similar to G. rubropusillum macroscopically. Both had the same basidiomata coloration, a sessile endoperidial body, and a distinctly delimited peristome, but G. rubropusillum could be distinguished by its smaller mature basidiomata (2.9–7.0 × 7.0– 9.5 mm), larger basidiospores (3.8–5.9 × 3.7–5.3 μm), and branched capillitial hyphae (Accioly et al. 2019). Geastrum courtecuissei P. - A. Moreau & Lécuru, which was found in Guadeloupe, also resembled G. villopannosum in the color of the pseudoparenchymatous layer, number of exoperidium lobes (4–8 lobes), and sessile endoperidial body (Accioly et al. 2019). However, G. courtecuissei differed in having a white tomentum endoperidium and larger basidiospores (3.8–5.0 × 3.7–4.9 μm) (Accioly et al. 2019). Geastrum javanicum Lév. and G. villopannosum were well characterized by the felted mycelial layer and unbranched capillitial hyphae, but G. javanicum differed from G. villopannosum by its deeply saccate expanded basidiomata, an indistinctly delimited peristome, and capillitial hyphae with densely granular protuberances (Teng 1963; Dring 1964; Zhou et al. 2007; Leite et al. 2011). Geastrum villopannosum and G. yunnanense, reported from China, shared similarly sized basidiomata (20–40 mm in diam.), a pseudoparenchymatous layer lacking a collar, and a distinctly delimited peristome (Yang et al. 2024). However, G. yunnanense could be easily distinguished based on the mycelial layer without debris, smaller basidiospores (2.0–2.5 × 1.9–2.5 μm), and rarely branched capillitial hyphae (Yang et al. 2024).