Tuber griseolivaceum L. Fan & K.B. Huang, 2017

Huang, Kaibing, Chen, Meng & Fan, Li, 2017, Tuber griseolivaceum sp. nov., a new olive-gray truffle species from China based on morphological and DNA data, Phytotaxa 309 (2), pp. 166-172 : 168-169

Tuber griseolivaceum L. Fan & K.B. Huang , sp. nov. ( Fig. 2 )

MycoBank: MB819588

Type: — CHINA. Yunnan Porvince: Xundian Country, in soil under forest dominated by Pinus yunnanensis Franch. , 14 Jan 2015, Cao 1567-1, FAN 469 ( BJTC).

Ascomata subglobose, 1.2–3.5 cm diam., olive gray, or gray with green tinges, surface regular or slightly wrinkled, sometimes with a few white furrows. Odor faint, taste not recorded. Peridium composed of two layers, 200–250 μm thick; outer layer pseudoparenchymatous, 75–125 μm, composed of subglobose cells of 7.5–15(–22.5) μm, thin-walled, hyaline; inner layer of interwoven hyaline hyphae, thin-walled, 3–5(–7.5) μm wide. Cystidia arising from the outermost cells of peridium, thin-walled, hyaline, 110–150 μm long and 3–5 μm wide at the base, 2–3 septate, tapered in the tips, abundant in the external furrows observed in the ascoma. Gleba firm, solid, brown when young, then blackish to black at maturity, marbled with large and scarce white or whitish veins. Asci subglobose to ovoid, 70–150 × 50–100 μm, hyaline, 1–3-spored, occasionally 4-spored, thin-walled, sessile at maturity. Ascospores hyaline to light brown when young, dark brown when ripe, regularly globose, measuring 35–42.5 μm (Χ = 39.2 ± 2.0, n = 30) in onespored asci excluding ornamentation, in two-spored asci 27.5–37.5 μm (Χ = 32.9 ± 2.6, n = 30); in three-spored asci 25–35 μm (Χ = 30.5 ± 2.9, n = 30); in four-spored asci (occasionally) 25–30 μm (Χ = 27.8 ± 2.5, n = 8), showing a reticulate mesh ornamentation with 3–4 (–5) alveoles across the ascospore diameter, about 4–6 μm high.

Diagnosis: —Differs from T. caoi by its cystidia of 110–150 μm long and 2–3 septate, and 3–4 (–5) meshes across the spore width, from T. pseudosphaerosporum L. Fan and T. parvomurphium L. Fan by its olive-gray ascomata.

Habit, habitat and distribution: —Hypogeous, gregarious, in soil under forest dominated by Pinus yunnanensis in Yunnan Province, China. Only known from China.

Etymology:— Referring to the color of ascomata.

Other materials examined: — CHINA, Sichuan Province: Panzhihua City, in soil under forest dominated by Pinus armandii Franch. , 29 Nov. 2014, Cao 1525, FAN434 (BJTC), Yunnan Province: Xundian Country, in soil under forest dominated by P. yunnanensis , 14 Jan. 2015, Cao 1567-2, FAN470 (BJTC).

Figures

FIGURE 2. Tuber griseolivaceum (BJTC FAN469, holotype). a. Ascomata. b–c. Scanning electron micrograph (SEM) of ascospore. d–f. Light micrograph (LM) of asci and ascospores.