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 Add this item to the list  804887 Original description
   
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Page number:110 
Remarks (internal):Zonate species with similar cap colours and milk that stains quickly sulphur to greenish yellow are European L. chrysorrheus, North American L. vinaceorufescens, and an undescribed American species [labeled L. aff. chrysorrheus in the phylogenetic tree and Table 1]. ITS sequence comparison suggests the new species described here is close to the three species but not conspecific.
Lactarius chrysorrheus is less sticky, which is reflected in the pileipellis structure, a loosely interwoven cutis without distinct slime layer (Heilmann- Clausen et al. 1998). Lactarius vinaceorufescens differs by a pileipellis with a relatively thin ixocutis and the lack of ixocutis in the stipitipellis (Hesler & Smith 1979). Lactarius xanthogalus Verbeken & E. Horak, described from Papua New Guinea (Verbeken & Horak 2000), has a zonate orange to paler cap and latex that becomes immediately sulphur yellow but clearly differs by the zebroid ornamented spores.
 
Description type:Original description 
Description:Lactarius indochrysorrheus K. Das & Verbeken, sp. nov. Plates 2, 3, 6a,b,e
MycoBank MB804887
Differs from Lactarius chrysorrheus by its more viscid pileus with its pileipellis an ixocutis covered by a thick gelatinous layer.
Type: India. Sikkim: North District, Dombang, 2743′35.2″N 8845′15.2″E, alt. 2920 m, 18.VIII.2011, K. Das, KD 11-002 (Holotype, BSHC; isotype, GENT).
Pileus 25-70 mm diam., convex with slightly pubescent and inrolled margin when young, gradually planoconvex to applanate with slightly depressed centre, rarely with a central papilla, sometimes becoming widely infundibuliform; margin decurved with maturity, becoming very irregularly wavy; surface smooth to greasy, viscid (sticky), shiny, brownish orange, pinkish buff to salmon (a: 45) or orange (b: 6A6) (cinnamon (a: 10) to somewhat rusty after maturity), gradually apricot cream to paler up to yellow (a: 5E), towards margin distinctly zonate with several zones over the whole diameter but most dense in the center; zones consisting of darker and watery spots; margin very faintly and shortly striate. Lamellae subdecurrent, crowded (18-22/cm at pileus margin), pale yellow (a: 4D) when young, gradually pink-spotted, finally becoming brown to reddish brown, with lamellulae in 9 series; edge entire, concolorous. Stipe 45-65 x 6-8.5 mm, slender, subcylindrical to cylindrical or slightly widened towards base; surface smooth, slightly greasy, strigose (hairy) at base, much paler than the pileus, especially in the upper part (very pale pinkish), very pale salmon to vinaceous, gradually darker up to rust to rusty tawny or pale brick red. Context hollow in stipe, pinkish yellow (a: 4D) to pale salmon, turning lemon yellow (a: 54) to greenish yellow (a: 57) after cut, changing to salmon (a: 45) with FeSO4, and greenish with Guaiac. Latex abundant, white, turning quickly to greenish yellow. Taste first mild, then becoming bitter and acrid. Odour not distinctive. Spore print pale cream (c: 10 Y).
Basidiospores 6.4-7.4-8.5 x 5.6-6.2-6.9 µm, (Q = 1.08-1.18-1.33), subglobose to ellipsoid; ornamentation amyloid, ≤0.9 µm high, composed of conical to spine-shaped warts, with short or medium, irregular to regular ridges which are aligned or connected and forming a partial to incomplete reticulum; some isolated small warts present; plage sometimes distinct and amyloid. Basidia 30-44 x 9-13 µm, 4-spored, subclavate to ventricose; sterigmata 2.5-4 x 1.5-2 µm. Pleuromacrocystidia 32-70 x 7.5-11 µm, fairly abundant, emergent ≤10-30 µm, narrowly clavate, cylindric with tapered apex or fusoid, often with mucronate to subcapitate apex, slightly thick-walled (wall ≤0.5 µm); content refractive. Pleuropseudocystidia filamentous, 3-5 µm wide. Lamellar edge fertile with basidia, cystidia and marginal cells. Cheilomacrocystidia 35-55 x 8-9 µm, moderately abundant, subclavate to narrowly clavate or ventricose to fusoid sometimes with mucronate apex; content refractive. Cheilopseudocystidia filamentous. Marginal cells 11-20 x 7-11 µm, mostly clavate to subclavate, often multiseptate. Hymenophoral trama with lactifers. Pileipellis an ixocutis, ≤170 µm thick, with gelatinous layer mostly extended 10-15 µm beyond the hyphal layer; hyphae repent to suberect, ≤3.5 µm wide, branched, septate. Stipitipellis an ixocutis, composed of repent hyphae mostly in parallel pattern; hyphae ≤3.5 µm wide, branched, septate. Stipe trama mostly with numerous nested sphaerocytes. Clamp connections absent.
Ecology & Distribution - Gregarious under Abies densa and Picea spinulosa in subalpine coniferous or mixed (coniferous and broadleaf) forest. August. Fairly common.
 
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