Lactifluus caliendrifer Froyen & De Crop Figs 1, 5, 6

Original diagnosis.

Basidiocarps small (up to 3.5 cm cap diam.) and turning brown when bruised. Cap very velvety to tomentose, white to cream-coloured. Stipe smooth to velvety, white. Context with smell fruity, strong. Latex copious, watery white to white, sticky, turning dark yellow to mustard brown; taste acrid and a bit bitter. Basidiospores broadly ellipsoid, (5.8) 5.9- 7.0-7.1 -7.9 × (4.5) 4.7- 5.6-5.7 -6.2 μm (n=40, Q = 1.12- 1.24 -1.41); ornamented with irregular and isolated warts which are up to 1 μm high. True pleurocystidia absent, but with sterile elements in the hymenium. Pileipellis a palisade to lampropalisade. L. caliendrifer differs from its sister species, L. russulisporus, by the abundant thick-walled marginal cells, very long pileipellis hairs and slightly smaller basidia and spores with more regular and lower warts.

Basidiomes rather small. Pileus 19-34 mm diam., planoconvex, sometimes centrally depressed; surface very velvety, dull, pruinose, tomentose, covered with hairs in tufts, white to cream-coloured, becoming brown after bruising; margin inflexed. Stipe 11-17 × 4-7 mm, cylindrical, centrally attached; surface smooth to velvety, white, turning brownish when bruised. Lamellae adnate to decurrent, narrow and thin, 0.5-1.5 mm broad, crowded, with 3 to 4 lamellulae of different lengths between 2 lamellae, whitish, concolorous with pileus and becoming brownish when bruised; edge entire, concolorous. Context white, changing to pale pinkish near pileipellis after a while, turning brown when broken (6E8) or sometimes paler caramel (6C6), or camel (6D4); smell fruity, strong; taste unknown. Latex copious, watery white to white, sticky, turning dark yellow (4C8) after a few minutes, later mustard brown (5E6) after 15 minutes; taste acrid and a bit bitter.

Basidiospores broadly ellipsoid, (5.8) 5.9- 7.0-7.1 -7.9 × (4.5) 4.7- 5.6-5.7 -6.2 µm (n=40, Q = 1.12- 1.24 -1.41); ornamentation amyloid, composed of irregular or isolated warts which are up to 1 µm high, sometimes connected by low ridges, but not forming a reticulum; plage inamyloid. Basidia 27-55 × 8-12 µm, subcylindrical to subclavate, thin-walled, mostly 4-spored; content oil-like to granular. Pleurolamprocystidia absent. Sterile elements cylindrical, 28-52 × 4-8 µm, thin-walled and up to 3-septate, slightly emerging, with terminal cells 6-28 × 4-7.5 µm . Pleuropseudocystidia rare to abundant, 4-10 µm diam., emerging, irregularly cylindrical; apex obtuse to subcapitate; content oil-like to granular. Lamellae edge sterile . Marginal cells 28-61 × 3-6 µm, often septate: with 1 to 5 septae, with terminal cells up to 47 µm long, thick-walled, occasionally branched; apex obtuse to subcapitate. Hymenophoral trama cellular, with lactifers. Pileipellis a palisade to lampropalisade, elements of the suprapellis 60-440 × 2.5-5 µm; cylindrical, septate, sometimes capitate, slightly thick-walled; subpellis composed of isodiametric, mostly thin-walled cells. Stipitipellis a trichoderm to lamprotrichoderm; ascending hyphae 10-75 × 3-6 µm, up to 2 septate, often thick-walled, apex obtuse to capitate. Clamp connections absent.

Distribution.

Known from Thailand.

Ecology.

Thai montane and dipterocarp forest, growing under Dipterocarpus, Lithocarpus, Castanopsis and Quercus .

Etymology.

Means 'wearing a wig’, referring to the long hairs in the pileipellis.

Conservation status.

Unknown.

Additional material examined.

Thailand. Thoeng district, Chiang Rai, alt. 420 m, 19°36'45"N, 100°04'00"E, Forest roadside, dry dipterocarp forest (Longan plantation), 20 August 2012, K. Jatuwong, Wisitrassameewong 392 (GENT, MFLU); Doi Pui, Chiang Rai, alt. 650 m, 19°49'26"N, 99°52'19"E, bamboo forest, 3 July 2012, leg.: Wisitrassameewong 378 (holotypus, GENT, isotypus MFLU).

Remarks.

Lactifluus caliendrifer differs from its sister species, L. russulisporus, by the abundant thick-walled marginal cells, very long pileipellis hairs and slightly smaller basidia and spores with more regular and lower warts.