Tuber tomentellum L. Fan & H. Y. Fu 2023, sp. nov.

Tuber tomentellum L. Fan & H.Y. Fu sp. nov. (FIG. 3)

MycoBank:—MB 846498

Diagnosis:—differed from other species by the large ascospores reaching 78.55 μm in length and the numerous hyphoid or seta-like hairs on the peridial surface of ascomata.

Etymology:— tomentellum, tomemtose, referring to the ascomatal surface covered with short woolly hairs.

Typification: — CHINA. Yunnan Province: Kunming City, in soil under a Pinus forest, Oct 2020, collected by Jinzhong Cao (BJTC FAN1340)

Description:— Ascomata 1.3–2.2 cm, yellow brown (#f4d28d) to grey brown (#654321), surface even and finely tomemtose, with an indistinctly basal depression. Odor mild, flavour not recorded. Gleba brown (#7c2f20) at maturity, marbled with large and rare white veins.

Peridium 200–300 μm thick, two-layered: outer layer 150–200 μm thick, pseudoparenchymatous, composed of subglobose to irregularly shaped cells of 7.5–32.5 × 5–25 μm, thin-walled, light brown (#f5dbc2) toward outside surface; inner layer 75–150 μm thick, composed of interwoven hyphae 4–7.5 μm wide, hyaline, thin-walled, septate. Hairs arising from outermost cells of the peridium, two types, hyphoid, flexible, and having obtuse ends, or seta-like, erect, and having sharp ends, 30–90 × 2.5–4 μm, hyaline, slightly thick-walled, 1–3-septa. subglobose or ovoid, 80– 110 × 50–75 μm, hyaline, thin-walled, 1–3-spored, sessile. Ascospores ellipsoid to broadly ellipsoid, brown (#a52a2a) at maturity, reticulate, negative in Melzer’s reagent, excluding ornamentation, in 1-spored asci 30–78.5 × 25.7–46 μm, Q = 1.07–1.96 (Qm =1.52 ± 0.45) (n = 30), in 2-spored asci 31.1–64.5 × 26.2–41.4 μm, Q = 1.1–1.75 (Qm =1.43 ± 0.33) (n = 30), in 3-spored asci 29.6–62 × 24.2–38.9 μm, Q = 1.07–1.76 (Qm = 1.42 ± 0.35) (n = 30), reticulum 4–6 μm high, 6–7 meshes across spore width.

Habit, habitat and distribution: —hypogeous, gregarious, in soil under a Pinus forest in Yunnan Province, China. Currently, only known from China.

Additional specimens examined: — CHINA. Yunnan Province: Dali City, Xiangyun County, in soil under forest of Pinus sp., 21 Oct 2020, Collected by Baoxiang Shi (BITC FAN1330); Kunming City, in soil under a Pinus forest, Oct 2020, collected by Baoxiang Shi (BJTC FAN1346).