Russulales » Russulaceae » Lactarius

Lactarius purpureus

Lactarius purpureus R. Heim ex R. Heim, Rev.

Index Fungorum number 332904

Pileus 20–115 mm diam., plano-convex with depressed center to almost applanate, becoming widely infundibuliform in age, always somewhat wavy knotty, irregular; surface with abundant small adpressed scales, slightly to strongly zonate with multiple zones in some specimens, glabrous, moist to dry but greasy, reddish brown (9C–E5–7), with darker scales on a paler background, darker in the center, paler at the margin; margin incurved to decurved, uplifted in age, very irregular, wavy to flabellate, smooth to slightly tomentose when young, glabrescent. Lamellae decurrent with tooth, rather dense (9–12 L+l/cm) with 2–3 series of lamellulae (not always with a regular pattern), reddish brown (9D4–5) when mature, sometimes anastomosing, 2–6 mm broad; edge entire, concolourous. Stipe 20–95 × 5.5–20 mm, irregularly cylindrical, sometimes bumpy; surface smooth, concolourous with pileus. Context moderately thick and rather firm, 2.5–8 mm thick, thin near the margin, pale pinkish to pale reddish brown in places where eaten by insects, brittle and hollow in stipe, greyish green (29D4–5) with 10%, KOH, unchanging with FeSO4; taste very acrid; smell fruity acidic, slightly applelike. Latex white, abundant, acrid, unchanging. Spore deposit unknown. Basidiospores 5.2–6–6.8–8.2 × 4.5–5.5–6.4–7.2 μm, (n = 160, Q = 1–1.09–1.2–1.33), globose to broadly ellipsoid; ornamentation up to 1.2 μm high, composed of ridges that are forming a subcomplete reticulum; some isolated warts or short ridges present; plage inamyloid. Basidia 40–60 × 7–10 μm, with sterigmata 4–9 × 1.2–2 μm, hyaline, sometimes with refringent contents, thinwalled, 2–4 spored, subclavate to cylindrical. Pleuromacrocystidia 44–115 × 8–16 μm, abundant, emergent, subfusiform, with acute or moniliform apex, hyaline, thin-walled. Pleuropseudocystidia 3–9 μm diam., abundant, emergent up to 25 40 μm, tortuous to cylindrical, sometimes branching, with lactiferous contents, thin-walled. Hymenophoral trama composed of interwoven, filamentous hyphae and lactifers. Lamellar edge heteromorphous; marginal cells 12–30 × 4–8 μm, subclavate to subcylindrical, hyaline, thin-walled, 1- septate, forming the top of a multiseptate chain of short elements; cheilomacrocystidia 35–55 × 6–9 μm, rather abundant, fusiform, with tapering to acute, seldom moniliform apex, thin-walled, with needle-like contents. Pileipellis a cutis to a trichoderm, 70–160 μm thick, composed of hyphae 2–4 μm diam.; underlying layer composed of sphaerocytes and filamentous hyphae, abundant pleuropseudocystidia and lactifers. Stipitipellis a cutis to a trichoderm, 50–80 μm, underlying layer composed of filamentous hyphae and sphaerocytes. Clamp connections absent.

 

Habitat and distribution: Gregarious in soil under Castanopsis diversifolia in montane primary forest. L. purpureus was described from Thailand and is known also from Papua New Guinea (Verbeken and Horak

2000).

Material examined: THAILAND, Chiang Mai Prov., West of Chiang Mai, ancient forest of Doi Suthep, on a wet gully slope with Dipterocarpus sp., 05 December 1957, Heim Th. 63 (PC, Holotypus) – Doi Suthep-Pui National Park, Sangrasabhasri Lane to Huai Kok Ma village, N18°48.62' E098°54.60', 1145 m alt., primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees, 22 June 2003, leg. D.E. Desjardin 7556 (CMU, GENT, SFSU) – ibid., primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees, 30 June 2003, leg. D.E. Desjardin 7600 (CMU, GENT, SFSU) – ibid., primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees,, solitary to gregarious on soil, 30.05.2004, leg. Huyen T. Le 99 (CMU, GENT, SFSU).– ibid., primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees, 30 July 2004, leg. Huyen T. Le 207 (CMU, GENT, SFSU) – ibid., primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees, 02 June 2005, leg. Huyen T. Le 258 (CMU, GENT, SFSU) – ibid., primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees, 24 June 2005, leg. Huyen T. Le 298 (CMU, GENT, SFSU) – ibid., primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees,, solitary to gregarious on soil, 24 June 06, leg. Huyen T. Le 446 (CMU, GENT, SFSU) – Doi Suthep-Pui National Park, Huai Kok Ma village, N18°48.402' E98°54.617', 1145 m alt., solitary to gregarious on the soil, primary montane forest with Castanopsis spp. and Lithocarpus polistachyus and other trees,, 29 August 2003, leg. Huyen T. Le 52 (CMU, GENT, SFSU) – Mae Taeng Distr., Tung Joaw village, N19°08.07' E098°38.09', 1423 m alt., solitary to gregarious on soil and leaves, in evergreen forest dominated by Castanopsis sp. and Pinus sp., 27 May 2004, leg. Huyen T. Le 94 (CMU, GENT, SFSU) – Mae Teng Distr., Tung Joaw village, hill ridge, N19°08.07' E 98°38.90', 1350 m alt., hypogeous in well decayed leaf litter in drier Castanopsis-dominated broadleaved forest, disturbed by fire, 21 June 2004, leg. A. Verbeken & R. Walleyn 04/35 (GENT), leg. Huyen T. Le 120 (CMU, SFSU).

 

Notes: Lactarius purpureus is recognized easily in the field because of the uniformly reddish purple colours, reminiscent of Hygrophorus russula, as already indicated in the original diagnosis by Heim (1962). Heim erected a different taxonomic group for this outstanding species, viz., “Squamosi” (invalid). The Conspecificity of the Thai and Papua New Guinean specimens is confirmed by the molecular data.

 

Fig. 1 Lactarius purpureus. a. Basidiocarp. b. Spores. c. Pleuromacrocystidia. d. Basidia. Scale bars = 10 mm (basidiocarp) and 10 μm.

 

Fig. 2 Lactarius purpureus. a. Cheiloleptocystidia. b. Marginal cells. c. Pleuropseudocystidia. d. Pileipellis. Scale bars = 10 mm (basidiocarp) and 10 μm.

 

Reference

Le HT, Nuytinck J, Verbeken A, Lumyong S, Desjardin DE. 2007 – Lactarius in Northern Thailand: 1. Lactarius subgenus Piperites. Fungal Diversity24(1), pp.173-224.

 

 

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