Trechispora laxa P. Zhang & P.T. Deng, 2023

Deng, Peng-Tao, Yan, Jun, Liu, Xiang-Fen, He, Zheng-Mi, Lin, Yuan, Lu, Ming-Xin & Zhang, Ping, 2023, Three coralloid species of the genus Trechispora (Trechisporales, Basidiomycota) in China: two newly discovered taxa and one reported for the first time, MycoKeys 99, pp. 153-170 : 153

Trechispora laxa P. Zhang & P.T. Deng sp. nov.

Figs 5 , 6 , 7

Diagnosis.

Differs from Trechispora havencampii by the loose branches and 4-spored basidia.

Type.

China, Hainan Province, Baoting County, Qixianling Hot Springs National Forest Park , 18°70′24″N, 109°69′35″E, 300 m asl, 31 July 2021, leg. P. Zhang (holotype MHHNU10714) .

Etymology.

laxus (Latin), loose, referring to the loose branching.

Basidiomata.

Solitary or scattered, fleshy consistency, 45-55 mm tall, 30-35 mm broad, fresh color (8B6-7), apices white when young but turning grayish purple (14B6) with age, drying pale grayish beige (4C3). Stipe single, white (1A1), 10-15 mm tall. Branches polychotomous from the stipe, dichotomous towards apices, not flattened, loose, divided 3-5 times, terminal branches relatively short and with color transitions to lilac, apices pale purple or white, acute, axils U-shaped. Taste and odor not recorded.

Micromorphology.

Context with parallel arranged hyphae, 2-4 μm wide; generative hyphae clamped, smooth, thin-walled, hyaline, no calcium oxalate crystals. Subhymenial hyphae branched and wide, 3-8 μm; ampullate septa present at the base of the stipe, up to 6-8 μm wide. Basidia 20-26 × 7-9 µm with four sterigmata 4-5 µm long and a basal clamp connection, hyaline, subclavate, barrel-shaped. Cystidia absent. Basidiospores [40/3/2] 5-6 × 3-4 μm [Q = 1.25-1.71(1.83), Qm = 1.46 ± 0.16], ellipsoid, slightly irregular, inner side slightly concave, aculeate or finely verrucose, spines 1-1.5 μm long, apex not sharp but blunt; hilar appendage obscured by spore ornamentation; usually uniguttulate; hyaline, thin-walled, inamyloid.

Habit and distribution.

Solitary or scattered, grows in soil in broadleaf forest; basidiomata generally occur in summer. Known only from the type locality in China.

Notes.

The branches of T. laxa are scattered, not dense, and the apices are white or lilac gray with age. In the field, T. laxa and Trechispora havencampii are similar because of their pale grayish brown coloration, but T. havencampii has dense branches, tips white and axils V-shaped, and 2-spored basidia with long sterigmata (5-9.5µm). Trechispora longiramosa differs from T. laxa by having long terminal branches, densely branched and white to honey-yellow tips. Trechispora sanpapaoensis has smaller basidia (11-26 × 5.5-11.0 μm) and a grayish brown stipe. Trechispora termitophila develops abundant basidiomata in active termite nests, but T. laxa generally grows in the soil of broadleaf forest. Trechispora foetida has a reddish brown to deep brown, flattened stipe, and branching in one plane. In comparison, T. laxa is flesh colored, turning grayish purple in the terminal branches, the branches are not flattened, the branches are not white, and the stipe is non-flat. An additional pigmented species, Trechispora robusta described from Brazil, is pale grayish with internodes irregular, branches flattened to subcylindrical, and inflated hyphae.

Figures

Figure 5. Basidiomata of Trechispora laxa (MHHNU 10714). Scale bars: 1 cm.

Figure 6. Microscopic features of Trechispora laxa (MHHNU 10714) a basidiospores b basidia.

Figure 7. Scanning electron micrograph of basidiospores of Trechispora laxa (MHHNU 10714).