Tuber badium S.P. Wan, 2017

Wan, Shanping, Xu, Wenjun, Tan, Nianwu, Wang, Yun, Zheng, Yi & Yu, Fuqiang, 2017, Three Excavatum species Tuber badium, T. depressum and T. verrucosivolvum from Sichuan Province, China, Phytotaxa 296 (3), pp. 228-238 : 233

Tuber badium S.P. Wan , sp. nov. ( Fig. 3 ).

MycoBank:—MB 818791

Type:— CHINA. Sichuan Province: Huidong County, in soil under forest dominated by P. armandii, Dec. 2012 , wsp090, HKAS 88789.

Ascomata subglobose, 2–3 cm in diam., firm, with typical basal cavities, covered with distinctly verrucose warts in some areas, with brown superficial furrows, yellow brown to brown; interior cavity surface covered with many fine, irregular scales and large warts, white to yellow when fresh. Peridium 50–480 μm thick including the 11–83 μm high verrucose warts, pseudoparenchymatous, the outer layer 35–169 μm thick composed of big, subglobose to subangular cells, 2–23 × 1.5–11 μm, pale brown or hyaline; the inner layer 15–333 μm thick, composed of intricately interwoven, hyaline and thin-walled hyphae, 1–4.5 μm in diam. Gleba solid, yellowish brown when mature, marbled with white-yellow veins. Gleba composed of hyaline, interwoven, thin-walled hyphae, 1–6 μm broad at the septa, the cells cylindrical interwoven to inflated, 1.5–22 × 1–13 μm. Odor pleasant. Taste not recorded. Asci globose to subglobose, pyriform, ellipsoid or irregular, (82–)89–130(–139) × (35–)37–97(–99) μm, hyaline, sessile or with a short or tall stalk, thin walled 1–2 μm thick, 1–4(5) spored. Ascospores broadly ellipsoid, ellipsoid, sometimes subglobose or globose, hyaline when young, becoming brown at maturity; excluding their alveolate-reticulate ornamentation, in 1-spored asci (32–)36–43(–51) × (25–)27–33(–37) μm, in 2-spored (32–)34–48 × 27–34(–35) μm, in 3-spored 33–44 × 26–31(–32) μm, in 4-spored (29–)31–40(–41.5) × 24–31.5 μm, and in 5-spored 32–37 × 25.5–29.5 μm; Q = 1–1.67, Qm = 1.36 ± 0.12; reticulum with 2–4 meshes along the spore length and 2–4 across, the alveolar walls up to 2–13 μm tall.

Diagnosis: — Tuber depressum differs in its thichker peridium (200–640 μm), fusiform ascospores and lower alveolar walls (2–9 μm). Tuber verrucosivolvum differs in its high verrucose warts (36–185 μm) and less numerous spores per ascus (1–4 spored).

Habit, habitat and distribution: —Hypogeous, in soil under forest dominated by P. armandii in Sichuan Province, China. Only known from China.

Etymology: —In reference to the brown and yellow color of the ascoma.

Figures

FIGURE 3. Tuber badium (HKAS 88789, holotype). a, c. Ascoma and sections. b. Peridium sections. d. Scanning electron micrograph of ascospore. e, f. Light micrograph (LM) of asci and ascospores.