Lactifluus ramipilosus Verbeken & De Crop.
MycoBank number: MB 815138; Facesoffungi number: FoF02057
Pileus 55 mm diam., convex to planoconvex with undeep depression in the center; surface soft, chamois-leather like and pruinose, almost smooth but slightly irregular, yellowish orange (5A3-4A4); margin entire, straight to slightly deflexed. Stipe 25 × 17 mm, strongly tapering downwards; surface pale yellow (4A2), slightly paler towards the lamellae, very finely fibrillose. Lamellae broadly adnate to decurrent, up to 4 mm broad, medium thick, brittle, yellow (4A3). Context whitish yellow. Latex not observed. Fig 2
Spores 5.6–7.2–8.9(9.1) × 5.5–6.2–7.2(7.3) μm, Q = 1.03–1.16–1.32, broadly ellipsoid, sometimes subglobose; ornamentation amyloid but very low and weakly developed, composed of low and irregular warts that are often connected by very fine ridges forming a partial reticulum; plage mostly not amyloid, but sometimes with a very weak central amyloid spot. Basidia 4-spored, with some rare 2-spored basidia present, 45–55 × 8–10μm, subcylindrical to subclavate, with guttate contents. True cystidia absent. Pleuropseudocystidia abundant, not emergent to slightly but distinctly abundant, 6–8μm diam., cylindric but often swollen at the apex, with rounded apex, with needle-like to granular content. Hymenophoral trama mixed with some hyphae present but especially abundant sphaerocytes of up to 25μm diam., with abundant lactifers. Subhymenium cellular. Lamellar edge sterile; marginal cells 15–28 × 6–8μm, subclavate to irregular, mostly hyaline, sometimes with refringent walls, sometimes with slightly needle-like content. Pileipellis lamprotrichoderm-like, composed of a layer of hyphae with 3–5μm diam., which are mainly horizontally arranged and often terminating in remarkable thick-walled hairs which are pericline to oblique; hairs thick-walled, 35–125 × 3–5μm, often branched, sometimes septate, sometimes tapering near paex, sometimes with rounded apex. Fig. 3
Material examined: THAILAND, Chiang Mai Province, Mae Taeng district, Baan Tapa (22 km marker along road 1095), N19°8′0″ E98°46′15″, alt. 829.6 m, on soil in mixed forest, with Dipterocarpus sp., Castanopsis sp., Lithocarpus sp. and Quercus sp., 31 July 2014, E. De Crop 14–503 (holotype in MFLU, isotype in GENT).
Fig. 1 Maximum likelihood tree of Lactifluus subg. Lactariopsis and L. subg. Rugati, based on ITS-LSU sequence data. Maximum likelihood bootstrap values >70 are shown. New taxa are in blue and species for which obtained sequences are based on type material have names in bold.
Fig. 2 a Lactifluus armeniacus (holotype) b Lactifluus ramipilosus (holotype).