Nigrohirschioporus violacaeruleum R. Saha, A.K. Dutta & K. Acharya, 2024

Saha, Rituparna, Dutta, Arun Kumar & Acharya, Krishnendu, 2024, Nigrohirschioporus violacaeruleum sp. nov. and a new record of Pallidohirschioporus brastagii (Basidiomycota, Hymenochaetales) from India, Phytotaxa 634 (2), pp. 131-142 : 137-139

Nigrohirschioporus violacaeruleum R. Saha, A.K. Dutta & K. Acharya , sp. nov.

( Figs. 2 , 3 )

MycoBank: MB847478

Diagnosis: —Differs from Nigrohirschioporus durus by annual, applanate basidiocarp with greyish violet upper surface, sometimes with deep blue patches; lilac grey pore surface turn dull violet on bruising; dark ruby tubes with white patches and presence of two types of broadly clavate to capitate apically encrusted cystidia.

Etymology: —The epithet ‘ violacaeruleum’ refers to the colour of the upper pileus surface.

Holotype: — India. West Bengal: Jalpaiguri District, Nagrakata , 26°88’10.3”N, 89°91’24.1”E, elev. 214 m, 6 October 2018, R. Saha & K. Acharya, RK−32/2018 (CUH AM784).

Basidiocarps annual, applanate, dimidiate, sessile, 30−50 × 20−35 mm in diam., 2−10 mm thick at base, woody, very hard on drying. Pileus upper surface azonate, at first velutinate, soon becomes glabrous, greyish violet (19B4) towards the periphery and sometimes deep blue (19D8) patches throughout the upper surface, sometimes warty towards base; margin acute, wavy, white (1A1), sometimes with deep blue (19D8) patches. Pore surface lilac grey (16C2), turns dull violet (16E3) on bruising; pores circular to angular, 7−10 per mm. Context fibrous, homogenous, greyish brown (10D3), 2−6 mm thick. Tube layer not stratified, dark ruby (12F3), sometimes with white (1A1) patches on tubes, 1−3 mm deep.

Hyphal system dimitic; generative hyphae thick-walled, clamped, sometimes simple septate, hyaline, branched, 3−6 µm wide. Skeletal hyphae thick-walled with narrow lumen, hyaline, unbranched, 5.5−12 µm wide, non-dextrinoid, cotton blue (−) ve. Two types of cystidia present: (1) apically encrusted, thick-walled, hyaline, clavate or broadly clavate to capitate skeletocystidia with obtuse apices, 6−12 µm wide, projecting up to 44.5 µm towards hymenium; (2) apically encrusted thin-walled, hyaline, broadly clavate to capitate small cystidia with obtuse apex, 9.5−13.5 × 5−6 µm in diam. Basidia broadly clavate, 4-sterigmate, thin-walled, hyaline, 8.5−9.5 × 5.5−6.5 µm in diam. Basidiospores ellipsoid to elongate, hyaline, thin-walled, smooth, aguttulate, non-amyloid, (3.5–)4.1–5.6(–5.9) × (2.4–)2.6–2.9(–3.0) μm, Z avg = 5.0 ± 0.9 × 2.8 ± 0.2 μm, Q = 1.2–2.1, Q avg = 1.8 ± 0.3.

Habit and habitat: —Gregarious on dead wood of angiosperm.

Additional specimens examined: — India. West Bengal: Jalpaiguri District, Nagrakata, 26°88’10.3”N, 89°91’24.1”E, elev. 214 m, 6 October 2018, R. Saha & K. Acharya, RK−34/2018 (CUH AM785).

Remarks: —The new species is quite exceptional. Distinguishing features of the taxon includes an annual basidiocarp; velutinate to glabrous, greyish violet and sometimes with deep blue patches on upper surface; lilac grey pore surface, circular to angular pores, 7−10 per mm; presence of two types of cystidia—apically encrusted, thick-walled large cystidia and apically encrusted thin to thick-walled small cystidia (9.5−13.5 × 5−6 µm); ellipsoid to elongate, basidiospores measuring 3.5−6 × 2.5−3 µm with mean Q value of 1.79.

Figures

FIGURE 2. Field photographs of basidiocarps. a–c basidiocarps of Nigrohirschioporus violacaeruleum in natural habitat, showing pileus and pore surface morphology (CUH AM784, holotype). Photographed by: R. Saha. Scale bars a–b = 20 mm.

FIGURE 3. Microscopic characteristics of Nigrohirschioporus violacaeruleum (CUH AM784, holotype). (a) Basidia, (b) Thin-walled cystidia, (c) Thick-walled skeletocystidia, (d) Skeletal hyphae, (e) Generative hyphae, (f) Basidiospores. Scale bars: (a–f) = 5 µm. Drawings by: R. Saha.