Lactarius crocatus

Lactarius crocatus Van de Putte & Verbeken

Basidiocarps medium-sized to large. Pileus 45–100 mm diameter, convex when immature, becoming applanate, subumbilicate or infundibuliform when mature, margin regular or slightly waving-undate, surface dry, slightly to strongly velutinous, pruinose or not, rugose at margin, with centre rugose or not, light orange (5A6), bright orange with ochraceous tinge (5A8–5B8–6B7) to cinnamon coloured (6C8), getting paler towards the margin or not. Lamellae subdecurrent to decurrent with tooth, whitish cream (3A4–4A4), discolouring brown (5C4–5D4–5D5) to dark brown (6E4–5F7) when bruised, crowded (14–20L+l/cm), narrow to broad (1.5–5 mm), with numerous lamellulae of different length, edge smooth and concolourous. Stipe 45–90×8–20 mm, cylindrical to slightly tapering downwards, centrally attached, surface dry, slightly velutinous or not, concolourous with pileus or paler, often getting paler towards the top. Latex copious, sticky, white, unchanging when isolated, unchanging in contact with lamellae or within few minutes to half an hour turning light brown (6D4–7D4), ultimately becoming dark coffee-and-milk coloured, pale yellowish brown (4A4–4A5) to pale orange brown (5A4) reaction with KOH 10%, occasionally becoming dark brown (5F6–5E6) after half an hour, taste mild. Context moderately thick in pileus, solid to stuffed in stipe, cream to pale yellow, but quickly turning brownish (5B2–5C3) after cut, smell fishy, taste mild. Macrochemical reactions context almost immediately turning yellowish (3A4) with KOH 10%, greenish grey to bluish grey (24D2–25E3) reaction with FeSO4 after a few seconds, then slowly darkening to dark greenish grey (1F3–1F4–1E3–29E3). Basidiospores 6.7–7.5–8.3–9.0(–9.1) × 6.2–6.8–7.4–8.2 (–8.5) μm, subglobose (Q=1.03–1.09–1.12–1.19); ornamentation amyloid; ridges up to 1.3–1.6 μm high, with rather sharp edges, forming a complete or incomplete, often irregular reticulum with rather small meshes, isolated warts occasionally present; strong amyloidity between the ridges; plage distally to almost complete amyloid. Basidia 40–70× 8–12 μm, clavate to subclavate, 4-spored, occasionally 2-spored. Pleurolamprocystidia 40–130×6–13(–14) μm; wall (1–) 2–6(–7) μm; rather long and broad, subcylindrical, fusiform, subfusiform to subclavate, acuminate or with obtuse apex, distinctly or slightly emergent, arising from the subhymenium, moderately to very abundant. Pleuropseudocystidia 2–7 μm diam., cylindrical to lobed or tortuose, apex obtuse and often capitate to moniliform, slightly to distinctly emergent, scarce to very abundant. Lamellae-edge fertile, composed of basidia and cheilocystidia. Cheilocystidia 20–105×3–11 μm, thin-walled and hyaline to thick-walled (0.3–4 μm), fusiform, subfusiform, subclavate or somewhat irregularly shaped, acuminate or with obtuse apex, sometimes with wavy outline. Hymenophoral trama cellular, with abundant lactifers and rosettes of sphaerocytes. Pileipellis a lampropalisade; subpellis 35–90 μm thick, composed of rounded to elongated or irregularly shaped, thick-walled cells (5–35×5–30 μm); terminal elements 10–70(–75) × 4–11 μm; wall 0.5–2 μm; subcylindrical to subfusiform with tapering apices, acuminate or obtuse apex, outline often wavy, often septate.

Studied material: THAILAND—Chiang Mai Province, Mae Taeng district, Ban Mae Sae, Highway 1095 near 50 km marker, N19°14.599′ E98°39.456′, alt. 1002 m, rainforest with Castanopsis armata, Castanopsis sp., Lithocarpus sp., Pinus kesiya, 28 July 2004, Le 202 (CMU, GENT, MFLU, SFSU)—ibid., 5 September 2004, Le 222 (CMU, GENT, MFLU, SFSU)—ibid., 5 September 2004, Le 224 (CMU, GENT, MFLU, SFSU)—ibid., 5 September 2004, Le 225 (CMU, GENT, MFLU, SFSU)—ibid., 5 September 2004, Le 234 (CMU, GENT, MFLU, SFSU)—Chiang Mai Province, Mae Taeng district, Ban Pha Deng, Mushroom Research Centre, N19°17.123′ E98° 44.009′, alt. 900 m, rainforest with Castanopsis armata, Erythrina sp., Dipterocarpus sp., Pinus kesiya, 13 July 2003, Le 17 (CMU, GENT, MFLU, SFSU)—Chiang Mai Province, Mae Taeng district, Ban Pha Deng, Pathummi- karam Temple, N19°06′28.8″ E98°44′47.3″, 1050 m, rainforest with Castanopsis armata, Dipterocarpus sp., Lithocarpus sp., 27 July 2008, Van de Putte 08-042 (GENT, MFLU)—Chiang Mai Province, Doi Inthanon National Park, junction of Highway, 1009 and road to Mae Chem, N19°31.58′ E98°29.64′, alt. 1700 m, humid montane rainforest with Castanopsis sp., Lithocarpus echinops, Quercus sp., 16 July 2008, Van de Putte 08-034 (GENT, MFLU)—ibid., 16 July 2008, Van de Putte 08-035 (holotype MFLU, isotype GENT)—ibid., 16 July 2008, Van de Putte 08-036 (GENT, MFLU)—Chiang Rai Province, Khun Chae National Park, N19°04′40.5″ E99°23′54.3″, alt. 936 m, rainforest with Castanopsis armata, Castanopsis sp., Pinus kesiya, 10 June 2005, Le 268 (CMU, GENT, MFLU, SFSU).

Fig. 1 ML phylogram of Lactarius volemus sensu lato from northern Thailand based on LSU, ITS and rpb2 nuclear sequences. Posterior probability values of the BI-MrModeltest analysis (runs 2–5) are added. Bootstrap values ≥75% and posterior probabilities ≥85% are shown. Underlined taxa occupy uncertain positions. Branches in bold lead to well supported clades. The following abbreviations are used: AV: A. Verbeken, AVRW: A. Verbeken & R. Walleyn, BB: B. Buyck, DED: D.E. Desjardin, DS: D. Stubbe, JV: J. Vauras, KIINA: M. Härkönen, KVP: K. Van de Putte, LTH: H.T. Le, N: M. Noordeloos, RH: R. Halling, RW: R. Walleyn.

Fig. 2 Lactarius crocatus: a. basidiocarps (holotype, Van de Putte 08-042), b. basidiospores (Le 222), c. basidia (Le 225), d. section through hymenium (Le 268), e. pleurolamprocystidia (Le 17, holotype, Le 224) f. cheilocystidia (Le 17, Van de Putte 08-034, Le 268, 224, 234), g. pseudopleurocystidia (Le 17, 224, 202, 225, Van de Putte 08-034)(scale bar = 10 μm, scale bar basidiocarps = 1 cm).