Geastrum artocarpicola X. Yang & C. L. Zhao, 2025

Geastrum artocarpicola X. Yang & C. L. Zhao sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3

Holotype.

China • Guangdong Province, Yangjiang, Jiangcheng District, Bitian Lake Park , 21°52'N, 111°58'E, elev. 27 m, on the living tree of Artocarpus , 7 June 2024, CLZhao 36079 ( SWFC). GoogleMaps

Etymology.

Artocarpicola (Lat.): referring to the species growing on Artocarpus.

Description.

Fruiting body: Unexpanded basidiomata 6–11 mm in diameter, 5–8 mm in height, pyriform to ellipsoidal, lightly pink to pinkish buff when fresh, pinkish buff to gray pink upon drying. Expanded basidiomata small sized, 0.8–2 cm in diameter, 0.7–1 cm in height. Exoperidium: shallowly saccate to deep saccate, dehiscence often less than halfway or halfway down, splits into 7–8 lobes at maturity, lobes 2–6 mm wide, tapered at the front end, rolled outwards, soft and thin upon drying. Mycelial layer gray pink, without debris, not easily dislodged. Fibrous layer white, tightly attached to the mycelial layer. Pseudoparenchymatous layer smooth surface, flesh-pink, easily exfoliation, dried thin, aseptic collar.

Endoperidial body: Globular, 4–6 mm in diameter, projecting apically, 1–2 mm length, sessile. Endoperidium slightly pink when fresh, pale mouse-gray upon drying, with a smooth surface under the dissecting microscope. Peristome: wide conical, fibrillose, lighter in color than the endoperidium, distinctly delimited.

Hyphal structure: Capillitial hyphae: 2–5.5 µm in diameter, thick-walled, tawny, unbranched, IKI –, CB –, tissues unchanged in KOH. Exoperidium mycelium layer outside, mycelium hyphae thick-walled, 3–5 µm in diameter; fibrous layer in the middle, formed of the interlacing filament tissue, fibrous hyphae slightly thick-walled, 3–4.5 µm in diameter; pseudoparenchymatous layer inside, formed of the angular cell structured, 12–31 × 7–21 µm.

Basidiospores: Spherical, (3 –) 3.5–4 (– 4.6) × (3.1 –) 3.5–4 (– 4.6) µm in diameter, yellowish brown to dark brown, IKI –, CB –; spore surface smooth or ornamentation verrucose, 0.4–0.6 (– 0.8) µm in length, Q = 1.01, Q m = 1.01 ± 0.01. Basidia 11–20 × 7–8 μm, bubble-shaped to flask shaped, with 6 inconspicuous basidial pedicels.

Additional specimens examined

(paratypes). China • Guangdong Province, Yangjiang, Jiangcheng District, Bitian Lake Park , 21°52'N, 111°58'E, elev. 27 m, on living tree of Dimocarpus , 30 July 2024, CLZhao 39927 ( SWFC) GoogleMaps .

Notes.

Based on ITS + nLSU + RPB 1 + ATP 6 data (Fig. 1 View Figure 1 ), the species G. artocarpicola was closely related to both species G. mirabile and G. laneum . The taxon G. artocarpicola resembles G. laneum and G. mirabile in sharing sessile of endoperidial body. However, G. laneum differs from G. artocarpicola due to its mycelial layer visible coarse short villus, and its delicately echinulate basidiospores surface ( Wang and Bau 2023); G. mirabile can be distinguished from G. artocarpicola by its expanded basidiomata which has a mycoderm at the base, and capillitial hyphae surface debris ( Zhou et al. 2007).