Pileus 25-55 mm diam., plano-convex, centre slightly depressed, often with an inconspicuous papilla; margin somewhat irregularly wavy and striate to slightly grooved, becoming irregularly crenate when older; surface velutinous, dry, dark cream-coloured (4B3/4, 5A2) to pale yellowish brown (5DE4-5) or warm coffee-and-milk coloured and with an olive brown tinge (4DE4) (slightly reminiscent of the colours of L. fluens Boud.), but paler towards the margin; extreme margin dark cream-coloured. Lamellae adnate or subdecurrent, rather distant to subdistant, 4-10 mm broad, often interconnected by anastomosing veins, abundant, short lamellulae present, whitish (5A2) or pale yellow to greyish yellow (4(5)AB3/4), staining pinkish, orange-pinkish or brownish pinkish by the latex; edge entire, concolourous. Stipe 20-45 × 4-10 mm, central or slightly eccentric, rather slender, equal or slightly tapering downwards, sometimes curved at base; surface dry, smooth, paler than lamellae, yellowish white (4/5A2/3), staining slightly dirty orangish pink (6C3/4) to orange (6A8) when bruised. Context rather thin in pileus, stuffed in stipe, white, staining pinkish or orange-pinkish after cutting (5A3, 6B4, 7A5, 7B6, 7C8, 8B5), remaining white in the centre of the stipe; smell faintly fragrant or mealy- spermatic, reminiscent of L. azonites (Bull.) Fr. Latex abundant, white or watery white, drying pinkish, unchanging when isolated.
Spore print colour unknown. Basidiospores (6.3) 7.8–7.9–8.4–9.1 × (5.8) 7.1–7.5–7.8–8.7 (8.9) μm (Q = 1.01–1.04–1.08–1.15; n = 120), globose to subglobose; ornamentation amyloid, a somewhat dense but incomplete reticulum with various free terminal ends, composed of rather irregular ridges that are 1.5-2 (2.5) μm high, more or less acute, sometimes with a split appearance and mostly irregularly crenulate edges; numerous isolated warts and short ridges present; plage distally amyloid. Basidia 35-75 × 10-15 μm, subclavate to clavate, mostly 4-spored but 1- and 2-spored basidia also present, sometimes with granular or guttate contents; sterigmata 2.5-10 × 1-3 μm. Pleuromacrocystidia absent. Pleuropseudocystidia 4-9 μm diam., scattered to moderately abundant, emergent, irregularly cylindrical, somewhat tortuous, sometimes branched. Lamellar edge mostly sterile; cheiloleptocystidia 6-36 × 3-7 μm, subcylindrical, subfusiform or subclavate, hyaline or with granular contents, thin-walled. Hymenophoral trama heteromerous; sphaerocytes intermixed with often somewhat inflated hyphae; lactifers moderately abundant to abundant. Pileipellis a trichopalisade to palisade, rather thin, 40-90 μm thick, containing pale brown, intracellular pigmentation, cell walls thin or slightly thickened and refringent, often a thin mucus layer present; suprapellis composed of long and slender terminal elements, 6-60 × 2-6 μm, cylindrical, subfusiform, sometimes subclavate, sometimes septate, mostly recumbent to repent, also upright; subpellis composed of few layers of inflated cells and hyphal elements, 10-25 × 10-15 μm, isodiametrically or irregularly shaped. Stipitipellis a cutis or trichoderm, 30-80 μm thick, hyaline.
Habitat and distribution: Solitary on the soil in montane mid-elevation rainforest with Quercus, Lithocarpus, Castanopsis, Dipterocarpus or Pinus.
In the field, L. friabilis might be confused with L. subplinthogalus var. chiangmaiensis due to the pale colours, the distant and broad lamellae, and the pink staining of the context. However, microscopically L. friabilis is easily distinguished by its reticulate spore ornamentation, whereas L. subplinthogalus var. chiangmaiensis has a distinctly zebroid ornamentation.