Tricholosporum tamilnaduense Kumar M, Agnes K. A & Nivetha M, 2025

Tricholosporum tamilnaduense Kumar M, Agnes K. A & Nivetha M sp. nov. ( FIGURES 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 .)

MycoBank:—MB 853682

Etymology:—Named after the type location “ Tamil Nadu ”, India.

Diagnosis:—The diagnostic features of T. tamilnaduense include the non-hygrophanous, broader, pale orangish pileus with a violet-white margin, hygrophanous lamellae, a short stem with an apex pruina, spores cruciform, measuring 4–6 × 3–4 µm, cystidia with a bulbous base or ampullaceous cystidia.

Holotype:— INDIA. Tamil Nadu: Tirupattur ( Alangayam ), 26 th October 2022, Agnes Kayalvizhi A, (GenBank Acc. No.: ITS = PP723084 ).

Description:— Pileus 3.5–5 cm broad, convex, broadly umbonate with shallow central depression, surface pale orangish (5A3), smooth, dry, non-hygrophanous, non-striate, margin violet white (15A2); incurved, becoming straight, edges irregular. Lamellae up to 2mm wide; pale lilac (15A5), emarginate, sub-decurrent, moderately crowded, hygrophanous turning brownish orange, lamellulae 3 lengths, edge irregular. Stipe 2.3–3.7 × 0.4–0.6 cm, central, surface lilac-brownish (14A2), apex by violet white (16A2) pruina, cylindric, solid, dry. Context 1–2.5 mm thick, white, consisting of thin-walled hyphae, inflated up to 23 µm, laticifers present, thick-walled, branched. Basidiospores 4–6 × 3–4 (4.7 ± 1.2 × 3.8 ± 0.4) µm, Q = 1.0-1.5, Q av = 1.24; star-like or cruciform, hyaline, thin-walled, with one or two refractive oil guttule in every spore, inamyloid. Basidia 17–23 × 5–7 µm, clavate, two to four spored, thin-walled, encrusted. Pleurocystidia and cheilocystidia similar, 16–35 × 6–9 µm; bulbous base, neck narrow, fusoid or mucronate apex, smooth. Hymenophoral trama regular, hyaline, made of parallel hyphae, hyphae 1–12 µm diam. Pilipellis an undifferentiated cutis, hyphae 4.5–7µm. Stipitipellis a cutis, 7.5–30 µm wide, septate, hyaline, thin-walled hyphae, terminal cells 55–92 × 17.5–30 µm, cylindrical. Clamp connections present in all tissues.

Habit and habitat:—Solitary or scattered, on broad-leaved humus soil, tropical dry forest, wide spread, appearing in autumn (October–December).

Distribution:—Currently known in India from Tamil Nadu State (Tirupattur–Alangayam).

Material examined:— INDIA, Tamil Nadu: Tirupattur (Alangayam), 12° 36’ 0’’ N, 78° 45’ 0’’, 26 th October 2022, Agnes Kayalvizhi A, specimen code: MCCHF220202.

Notes:—Based on the morphology of 16 reported species, T. tamilnaduense is very close to T. guangxiense (Bau & Mou 2021) in the dimensions of basidiomata (3.5–5 cm), spores (4–6 × 3–4 µm) and basidia (17–23 × 5–7 µm). However, the cystidia dimensions are different from those of T. guangxiense (Bau & Mou 2021) . Moreover, T. tamilnaduense shows remarkable differences in the colour of the pileus, lamellae, and stipe of the basidiomata. The colour of T. tamilnaduense pileus is pale orangish with a violet-white margin, and the stipe is brownish lilac, while T. guangxiense (Bau & Mou 2021) pileus is greyish ruby to light lilac or greyish violet, and the stipe is light violet to violet. The lamellae colour of T. tamilnaduense is pale lilac to white lilac, while T. guangxiense (Bau & Mou 2021) is light violet to deep violet.

Although the basidiomata colour of T. goniospermum (Bres.) Guzmán ex T.J. Baroni (1982) and T. haitangshanum (Yu Li & J.Z. Xu 2018) slightly resemble T. tamilnaduense , but they vary largely in the dimensions of the basidiocarp, which measures 10–12 cm and stout stem 3–5 × 0.5–0.8 cm. Further, T. atroviolaceum (Murrill) T.J. Baroni 1982 ), T. caraibicum ( Angelini, Contu & Vizzini 2014) , and T. porphyrophyllum (S. Imai) Guzmán ex T.J. Baroni 1982 ) are close to T. tamilnaduense in the dimensions of the basidiomata alone but show large variation in colour and spore size.