Holotype (PDD 27088); Isotype (Herb. HK. ZT 68/309): 'Westbay of Lake Rotoiti, Prov. Nelson, N.Z.; leg. Horak, 29.IV.1968'.

Pileus 10-20 mm diam., hemispherical or convex when young becoming expanded or even concave, deep orange to apricot yellow (like Mycena fibula [Fries]), darker at the centre, dry, glabrous, slightly striate at the margin. Lamellae broadly adnate to subdecurrent, light orange, frequently connected by anastomoses at the bottom, close, gill edge concolorous. Stipe 20-40 x 2-4 mm, fusoid or rarely cylindric, concolorous with pileus, dry, glabrous, fistulose, often curved. Context orange, not waxy. Taste and odor not distinctive. Chemical reactions on Pileus: KOH, HCl- negative. Spores 4.5-5.5 x 4-5 µm, subglobose to ovoid, smooth, inamyloid. Basidia 30-35 x 5-6 µm, 4-spored. Cystidia lacking. Gill trama interwoven. Cuticle a cutis of repent, irregularly interwoven, cylindric, not gelatinized hyphae (2-7 µm diam.). Clamp connections present.

Amongst mosses under Leptospermum scoparium (and Nothofagus cliffortioides). New Zealand.

Pileo 10-20 mm lato, e convexo plano vel concavo, aurantiaco, sicco, glabro. Lamellis late adnatis vel decurrentibus, pallide aurantiacis. Stipite 20-40 x 2-4 mm, fusoideo, pileo concolori, sicco. Sporis 4.5-5.5 x 4-5 µm, subglobosis. Epicute ex hyphis cylindraceis, haud gelatinosis cutem formantibus. Septis fibulatis. Ad terram in silvis Leptospermum. Novazelandia.

Holotypus (PDD 27088) ‘Lake Rotoiti, N.Z.; leg. Horak, 29.IV.1968'.

SPECIMEN: cf. Stevenson (1962: 1.c.).

Pileus -20 mm, hemispherical to convex becoming expanded with upturned margin; brilliant orange to apricot, red tints absent; dry, glabrous to minutely fibrillose, not hygrophanous, scarcely striate at margin. - Lamellae 8-10 (1 -1) broadly adnate-decurrent to arcuate, occasionally anastomosing,. pale orange, edges concolorous, entire. - Stipe 20-40 x 1.5-3 (-4) mm, cylindrical, equal to subfusoid;  concolorous with pileus or paler; dry, glabrous to innately fibrillose, solid becoming fistulose, single; or caespitose. - Context pale orange. - Odour and taste not distinctive. - Chemical reactions on pileus: KOH - negative. Spores 4.5-5.5 x 4-5um, globose to subglobose or obovoid. - Basidia 30-35 x 5-6um, 4-spored. - Cystidia absent. - Pileipellis a cutis of interwoven, cylindrical hyphae (2-7 um diam.), membrane subgelatinised, encrusted with pigment; clamp connections present (Pl. 1, Fig. 5)

Material Examined Watagan State Forest, NSW, 10.v.1982, A.E. Wood, UNSW 82/271; Monga State Forest, NSW, 18.v.1983, A.E. Wood, UNSW 83/771(a); Megalong Valley, NSW, 19.6.1983, H. Ramsey, UNSW 83/948; Blackheath, NSW, 23.vi.1983, A.E. Wood, UNSW 83/987; Blackheath, NSW, 23.vi.1983, A.E. Wood, UNSW 83/988; Bola Creek, NSW, 7.vii.1983, F. Taeker, UNSW 83/1052; Monga State Forest, NSW, 16.v.1984, A.E. Wood & N B. Gartrell, UNSW 84/539; Mt. Wilson, NSW, 26.iii.1988, A.E. Wood, UNSW 88/17; Lake Rotoiti, NZ, 29.iv.1968, E. Horak, PDD 27088 (holotype).

Pileus (6)10-20 mm, convex (occasionally slightly umbonate), expanding to plano-convex; smooth, dry, apricot-yellow to light orange (9J7-9I11, M&P), usually darker at the centre, all parts fading with age; red tints completely absent; a little pellucid striate if moist, especially towards the margins; margins usually slightly crenulate, especially when young. Lamellae adnate-arcuate to usually subdecurrent; occasionally anastomosing; not especially thick, widely spaced to distant, very frequently connected by veins on the undersurface of the pileus; pallid apricot or pileus tinted, margins concolorous. Stipe 17-44 x 1.5-3.5 mm, cylindrical but often tapers towards the base, smooth, dry, hollow, pale apricot-yellow to similar to pileus but paler at the base to near white.
Spores (3.5)4.0-6.5 x 3.5-4.5(5.0) µm, mean 5.2 x 4.2 pm, Q: 1.0-1.6, mean Q: 1.2-1.3, mostly subglobose but occasionally sublacrymoid, smooth, hyaline, non-amyloid. Basidia 30-41(42.5) x 4.5-7(8) µm, mean 34 x 6 µm, Q: 4.4-7.5, mean Q: 5.7, 4-spored (occasional 2-spored forms exist, see discussion below), clamped, sometimes with medallion clamps. R: 6.5. Cystidia absent. Hymenophoral trama subregular to irregular, composed of hyaline, thin-walled, septate, semi-inflated, at least partially interwoven hyphae 20-90(120) x 3-12(15) µm, frequently constricted at the septa and often with medallion clamps. Pileipellis a cutis, (often some hyphae partially gelatinise to give the appearance of an ixocutis, but fresh material is not viscid), cuticular hyphae 1-3 µm diameter, clamped, forming a repent layer 20-40 µm deep overlying a subpellicular layer of hyaline, clamped, inflated cells 40-80 x 6-12 µm, cuticular pigment plasmatic and also as granules on the hyphal walls. Stipitipellis a cutis of hyaline, thin-walled, inflated, clamped hyphae 2-4 µm, sometimes overlain with a loose layer of extensively branched, thin-walled, clamped hyphae 3-8 µm; subpellis an array of inflated, thin-walled, hyaline, clamped, parallel elements 6-11 µm.

Gregarious on soil in rainforest.

Remarks This New Zealand species is present in Tasmania (Fuhrer and Robinson 1992) and New South Wales. It is close to the New Zealand species Hygrocybe apricosa Horak but that taxon has spores which are ellipsoid (4-5 x 2-2.5 µm), has no cuticular layer of thin hyphae, and is deep apricot-orange. Herbarium material of aurantiopallens is always a dull orange and the cross veins can readily be seen on the pileus undersurface. Some collections of aurantiopallens contain large numbers of 2-spored basidia which do not significantly differ from the dimensions of 4-spored basidia but which do produce larger spores (5.5-7(8) x 4.5-6 µm; mean: 6.3 x 5.1 µm). Both spore ranges can be found on the same basidiome and apart from the 2-spored basidia; there are no other significant differences.