Pileus 50–135 mm diam., convex with distinct depression and inrolled margin to plano-convex with deep funnel-shaped depression, infundibuliform; surface pale yellow (3A2–3 in young specimens) or slightly darker and more brownish (sometimes 4B5 in older specimens) with darker to reddish brown scales, with darker zonations, more orange brown on disc, viscid, not hygrophanous, in some specimens woolly; zonations sometimes formed out of the woolly covering, sometimes formed out of watery spots; distinct scales present in some specimens, composed of ascending hairs especially in the center, sometimes dirty brown mottled; margin involute and strongly tomentose in young specimens, bearded, then decurved and with hairs forming pendulous agglutinations, brownish to dirty reddish brown; margin not striate but some slightly grooved aspect visible in between the zonations. Lamellae subdistant (6 L+l/cm), decurrent with very long tooth (more than 10 mm in some specimens), with abundant lamellulae (especially short ones), brittle, rather thick, up to 11 mm broad, cream-coloured, staining dirty greyish brown by the latex with some pinkish brown shade; some intervenation present close to the stipe in young specimens; edge concolourous, entire. Stipe 25–115 × 15– 35 mm, cylindrical in younger basidiomes to subcylindrical and ventricose or very irregular in older basidiomes, tapering downwards; surface pale yellow (3A2–3) or darker, locally dirty brownish, smooth, often with very large, ellipsoid scrobicules that are sometimes concolourous, sometimes slightly darker. Context very firm and thick in the pileus, hollow in the stipe, cream- coloured to whitish, with watery zonation present inside the pileus, changing slowly greyish when cut; taste very acrid after a while in young specimens, less distinct in older specimens; smell sweetish, like Lactarius zonarius. Latex very abundant, white to watery cream-coloured, unchanging, but staining paper slowly yellowish, staining lamellae dirty greyish brown, but unchanging when drying; taste burning acrid.
Basidiospores 7.2–8.9–10.5–12.2 × 7–8.4–9.2–10.2 μm (n = 160, Q = 1– 1.05–1.14–1.28(–1.33) subglobose to broadly ellipsoid; ornamentation up to 2.5 (–3.5) μm high, forming an incomplete reticulum, often in a partly spiral pattern, composed of acute and locally high ridges that are connected by lower and fines lines; plage inamyloid. Basidia 50–65 × 13–18 μm, sterigmata 5–11 × 2–3.5 μm, hyaline, 4-spored, thin-walled, subclavate. Pleuropseudocystidia abundant, rarely emergent, 6–9 μm diam., thin-walled, tortuous to cylindrical, with lactiferous contents. Pleuromacrocystidia abundant, sometimes with refringent contents, emergent and arising from deep in the subhymenium, 55– 100 × 9–20 μm, subclavate to subfusiform with tapering, sometimes moniliform, sometimes rather rounded apex, thin-walled; contents granular and guttate. Hymenophoral trama composed of interwoven, filamentous hyphae. Lamellar edge heteromorphous; marginal cells hyaline, thin-walled, 13–26 × 3–8 μm, 1-septate, shortly clavate, irregularly cylindrical to fusiform. Pileipellis an ixocutis to an ixotrichoderm, 90–240 μm thick, underlying layer composed of filamentous hyphae and sphaerocytes. Stipitipellis an ixocutis, 70–160 μm thick, underlying layer composed of filamentous hyphae and sphaerocytes. Clamp connections absent.
Habitat and distribution: solitary on the soil, in rainforest dominated by Castanopsis sp., Dipterocarpus sp., and Lithocarpus sp.; so far only known from Thailand.