Lactifluus armeniacus De Crop & Verbeken, sp. nov.
MycoBank number: MB 815137, Facesoffungi number: FoF 02056, Figs. 1, and 2
Etymology – Referring to the apricot-coloured basidiocarps.
Holotype – MFLU E. De Crop 14–501

Pileus 69 – 72 mm diam., planoconvex with central depression to slightly infundibuliform; margin sometimes slightly striate, sometimes concentrically wrinkled; edge rather irregular, sometimes crenulate or locally undulate; surface chamois leather-like, locally wrinkled but smooth in the centre, pruinose, bright orange(as 5B5/6, but more yellow), unicolourous. Lamellae adnate with decurrent tooth to subdecurrent, distant (2 L+1 l / cm– 4 L+ 3 l / cm), bright orange to yellow (4A3 to 4/5A4), very broad, rather thick and brittle, slightly intervenose; edge entire and concolourous. Stipe 27 – 28 × 11 – 18 mm, cylindrical to slightly tapering downwards, sometimes curved, centrally attached to pileus; surface very soft, pruinose and finely striate, concolourous with pileus (bright orange 5B5/6 with a more yellowish tinge). Context solid and quite firm, white, unchanging; taste sweet, mild; smell not distinctive. Latex abundant, white, unchanging; taste
sweet.
Basidiospores broadly ellipsoid, sometimes subglobose, sometimes ellipsoid, 6.4 – 7.7 – 9 × 5.1 – 6.2 – 6.7 μm (n = 20, Q = 1.11 – 1.24 – 1.41); ornamentation amyloid, forming an almost complete reticulum, composed of very low warts connected by fine ridges, up to 0.2 μm high; plage inamyloid. Basidia 4 – spored, sometimes 2 – spored, 59 – 71 × 8 – 9 μm, cylindric to subclavate, with refringent to slightly thickened walls; content guttate to granular. Pleurolamprocystidia abundant, slightly emergent up to 17 μm, cylindrical, septate, 50 – 80 × 4 – 8 μm, with slightly thickened walls (<1 μm). Pleuropseudocystidia very scarce, 7 – 9 μm, cylindrical, mostly collapsed at apex; content granular. Lamellae-edge sterile; completely composed of cheilolamprocystidia which are 41 – 45 × 4 – 7 μm, cylindrical, septate, thick-walled. Hymenophoral trama cellular, with abundant lactifers and sphaerocytes. Pileipellis a lampropalisade; elements of the suprapellis 28 – 64 × 3 – 5 μm, cylindrical, obtuse, thickwalled; subpellis 132 – 174 μm thick, sphaerical cells 9 – 22 μm diam., with thickened wall. Stipitipellis hymeniderm; elements of the suprapellis 15 – 26 × 5 – 11 μm, cylindrical to clavate, sometimes with strong congophilous content, thickwalled.

Material examined – THAILAND, Chiang Mai Province, Mae Taeng district, Baan Tapa (22 km marker along road 1095), N19°7′45″ E98°46′1″, alt. 766.8 m, on soil in mixed forest, with Dipterocarpus sp., Castanopsis sp., Lithocarpus sp. and Quercus sp., 31 July 2014, E. De Crop 14–501 (holotype in MFLU, isotype in GENT).

Fig. 1 a Lactifluus armeniacus (holotype) b Lactifluus ramipilosus (holotype)

Fig. 2 Lactifluus armeniacus (holotype) a Section through pileipellis b Basidiospores c pleuropseudocystidia d Pleurolamprocystidia e Marginal cells f Bsidia g Terminal elements of the pileipellis. Scale bars: a – g = 10 μm.