82. Laccaria indohimalayana K. Das, I. Bera & Vizzini, sp. nov.

(Figs 6-8)

Distinct from similar looking Laccaria spp. mainly by nrITS data and the large basidiomata with pileus measuring 40-95 mm diam. and stipe 80-150 × 12-65 mm.

TYPUS. — India. Sikkim, South district, between Rayong and Damthang, 27°15.258’N, 88°21.643’E, 2244 m a.s.l., under Castanopsis sp. in temperate broadleaf forest, 24.VIII.2017, Kanad Das, KD 17-20 (holo-, CAL [CAL 1754]!).

MYCOBANK. — MB 830142.

GENBANK. — MK584157 (nrITS, holotype), MK575505 (nrITS).

ETYMOLOGY. — Referring to the Indian Himalaya (“indohimalayana”) in the state of Sikkim, the type locality.

OTHER SPECIMENS EXAMINED. — India. Sikkim:East district, Fambon Lho wildlife sanctuary, 27°21.631’N, 88°33.922’E, 2098 m a.s.l., under Castanopsis sp. in temperate broadleaf forest, 26.VIII.2017, Kanad Das, KD 17-46 (CAL[CAL 1755]).

DESCRIPTION

Pileus

40-95 mm diam., plano-convex to applanate, gradually infundibuliform when mature and radially sulcate throughout; surface glabrous, hygrophanous, brownish orange/Sahara when wet and light orange when dry; margin wavy to irregularly lobed, sometimes slightly uplifted at maturity.

Lamellae

Subdecurrent, subdistant to rather close (8-9/cm at pileus margin) at maturity, greyish red to dull red or paler or concolorous to pileus, unchanging on bruising; edge entire; lamellulae present in 5 series.

Stipe

80-150 × 12-65 mm, twisted, strongly fibrillose-striate, darker than pileus, brown with silky to pinkish fibrils, surface wet, base strigose with whitish to pink-white basal mycelium.

Context

Pithy.

Odor

Strong fungal smell.

Spore print

White.

Basidiospores

6.88-7.60-8.26 × 6.59-7.19-8.09 Μm, (n = 30, Q = 1.01-1.02- 1.13), mostly subglobose, sometimes globose; ornamentation inamyloid, echinulate; under SEM ornamentations composed of long dense spinoid warts (0.9-1.5 × 0.8-1.0 Μm) with intermediate small isolated warts (0.4 × 0.5 Μm) never forming any reticulum, with shorter warts always surrounding hilum area; hilum blunt; suprahilar plage inamyloid.

Basidia

25-44 × 9-11.5 Μm, clavate or rarely subclavate, 2- to 4-spored; mature sterigmata 3-7.5 × 2-2.5 Μm.

True hymenial cystidia

Absent.

Sterile cells on face of lamellae

Common, 15.5-39 × 3-5 Μm, mostly cylindrical with rounded apex, often with sub-fusoid apex, thin-walled, hyaline.

Sterile cells on edge of lamellae

18.8-28.6 × 3.6-6.0 Μm, cylindrical with rounded to subfusoid apex, thin-walled, hyaline.

Hymenophoral trama

Up to 95 Μm thick, composed of subparallel to interwoven, cylindrical, hyaline hyphae (3-5.5 Μm wide); subhymenium undifferentiated.

Pileipellis

Up to 100 Μm thick, a cutis composed of repent, parallel to subparallel, mostly interwoven, cylindrical, hyaline, with walls up to 1 Μm thick, hyphae (4.5-9.5 Μm wide).

Stipitipellis

Composed of repent, subparallel, interwoven, cylindrical, hyaline hyphae (3-10 Μm wide);

Caulocystidia

Absent.

Clamp-connections

Present in all tissues.

NOTES

This Asian species is characterized by the combination of a large (40-95 mm diam.) brownish orange pileus,very tall (80-150 mm) darker stipe with white basal mycelium and strigose base,mediumsized globose to subglobose (Q = 1.01-1.02-1.13) basidiospores ornamented with isolated spines up to 1.5 Μm high mixed with smaller intermediate warts, and its occurrence under broadleaf trees in temperate forests.Some species like Laccaria laccata (Scop.) Cooke, L. proxima (Boud.) Pat., L. torosa H.J. Cho &Y.W.Lim, L. pseudomontana Osmundson et al., L. versiforma H.J. Cho & Y.W. Lim are somewhat similar, but all these close taxa have a much smaller pileus and shorter stipe. Moreover, the European L. laccata has subglobose to broadly ellipsoid (Q = 1-1.3) basidiospores, while the European L. proxima has also subglobose to broadly ellipsoid (Q = 1.2-1.35), larger basidiospores (8-11[12.5] ×[6.5]7-8.7[9.2] Μm) with spines <1Μm high, and a pileus which is squamulose at centre. The Asian L. torosa lacks a strigose stipe base with white basal mycelium, while L. versiforma possesses spines “1 Μm in length”.The North American L. pseudomontana has basidiospores with fine spines “1 (-1.8) Μm in length, 0.4- 0.6 Μm wide at base” (Mueller 1992; Vellinga 1995; Osmundson et al. 2005; Vesterholt 2012; Cho et al. 2018). Another recently discovered Indian species, L. violaceotincta K.P.D. Latha et al., occurs in the tropical region and has distinctively smaller greyish violet coloured basidiomata with pileus 4-38 mm diam. and stipe 16-50 × 1.5-4 mm (Latha et al. 2019).

Our nrITS-based phylogenetic analysis (Fig.6) suggests, however without support, that the new species (MK584157 and MK575505) is sister to a subclade bearing L.proxima (JX504152) and two samples from Portugal,submitted in NCBI as L.bicolor, but apparently representing a still undescribed species.Other suggested, phylogenetically close species include the Asian L. parva H.J. Cho & Y.W. Lim and American L. pseudomontana .

Order RUSSULALES Kreisel ex P.M.Kirk, P.F.Cannon & J.C.David Family RUSSULACEAE Lotsy