Lactarius singeri Uniyal, K. Das & R.P. Bhatt

Uniyal, Priyanka, Das, Kanad & Bhatt, R. P., 2018, Two novel species of Lactarius subgenus Plinthogalus from Uttarakhand Himalaya, Phytotaxa 338 (3), pp. 255-264 : 260

Lactarius singeri Uniyal, K. Das & R.P. Bhatt Figs. 4 & 5

Mycobank:—MB823797

Etymology:—In recognition of Rolf Singer for his contributions to fungal taxonomy.

Type:— INDIA. Uttarakhand: Chopta-Baniyakund, 2475 m, N 30º29.259ʹ E 079º10.039ʹ, 01 August 2015, P. Uniyal, PU-804 (holotype, CAL).

Diagnosis:—Differs from Lactarius lavandulus by the absence of lilac discoloration in context and lamellae.

Description:— Pileus 55–69 mm diam., convex when young, plano-convex at maturity, centre slightly depressed, umbonate; surface dry, rugose, strongly rugose near margin, brown (6E4–5) or brownish grey (6F7) to dark brown (7A7–8); margin undulate to crisped, decurved. Lamellae subdecurrent, light orange (5A4–5) to greyish orange (5B4), edges dark brown (7A7–8); crowded (19–21 L+l/cm), unchanged when damaged; lamellulae in 4–5 series. Stipe 55–76 × 5–13 mm, cylindrical, concolorous to pileus. Context white, unchanged on exposure, stuffed in stipe; unchanged in FeSO 4 and KOH, brownish red (8D7–8) in guaiacol. Taste mild, odour insignificant. Latex scarce, watery white, changing light orange to orange (6A5–6) on lamellae; taste mild. Spore deposit pale yellow (4A3).

Basidiospores 7– 7.9 –9.5 × 6– 7.5 –8.5 μm, (n = 40, Q = 1– 1.06 –1.15), globose to subglobose, ornamentation 1.5–2 μm high, composed of round to conical warts and winged ridges forming a dense, incomplete reticulum; plage amyloid. Basidia 41–62 × 10–13 μm, subclavate, 2-, 4-spored; sterigmata 4.5–6 μm long. Lactifers in hymenophoral trama up to 10 μm diam. Pleuromacrocystidia absent. Pleuropseudocystidia abundant, 4.5–7 μm diam., unbranched to frequently branched, tortuous at base. Cheilomacrocystidia absent. Cheiloleptocystidia abundant, 21–43 × 4.5–8 μm, cylindrical, round apex; brown in KOH. Pileipellis a palisade, 41–82 μm deep; suprapellis composed of subglobose, subclavate to cylindrical cells, 10–38 × 4–10.5 μm, aseptate, with brown intracellular pigment; subpellis cellular, 2–3 layered, often with lactifers. Lactifers in pilear trama up to 8 μm diam. Stipitipellis a trichoderm, up to 102 μm deep, terminal cells septate to aseptate, cylindrical, with round apex and with intracellular brown pigment.

Habit and habitat:—Gregarious, under Quercus sp. and Abies sp. in subalpine mixed forest.

Specimens examined: INDIA. Uttarakhand, Rudraprayag, Chopta-Baniyakund , 2475 m, N 30º29.259ʹ E 079º10.039ʹ, 01 August 2015, P. Uniyal, PU-804 (holotype, CAL) ; Rudraprayag, Chopta-Baniyakund , 2549 m, N 30º29.121ʹ E 079º10.360ʹ, 08 August 2017, P. Uniyal, PU-1555 (Isotype, GUH) .

Figures

FIGURE 4. Lactarius singeri a. Fresh basidiomata in field; b. Marginate edges of lamellae and watery white latex; c. Pseudocystidia in hymenium; d. Transverse section through pileipellis; e. Cheiloleptocystidia; f. Stipitipellis; g. SEM images of basidiospores. Scale bars: a = 25 mm; c–d = 25 μm; e–f = 50 μm; g = 2 μm. Photos by: Priyanka Uniyal.

FIGURE 5. Lactarius singeri a. Dissected basidiomata; b. Basidiospores; c. Basidia; d. Pseudocystidia; e. Cheiloleptocystidia; f. Pileipellis. Scale bars: a = 10 mm; b–e = 10 μm; f = 20 μm. Drawings by: Priyanka Uniyal.