Agaricales » Physalacriaceae » Oudemansiella

Oudemansiella aff. crassifolia

Oudemansiella aff. crassifolia Corner.

Index Fungorum number: IF 413648; MycoBank number: MB 431169


Basidiocarps small to medium-sized. Pileus 18-38 mm in diam, circular, plano-convex, slightly depressed, sometimes concave, grayish yellow (4B3) to yellowish brown (5E7) at disc, yellowish white (4A3) to grayish yellow (4B4) towards the margin, viscid when moist; contexts yellowish white, 1.5-3 mm thick at disc, fleshy. Lamellae ventricose, narrowly adnate, yellowish white (4A2), with 4-6 series of lamellulae, close to subdistant. Stipe 12-30 × 1.5-5 mm, cylindrical, occasionally subcylindrical, central, curved, fibrous, solid, surface yellowish white to orange grey; non-annulus; base of stipe subdiscoid enlarged; pseudorrhiza absent.

Basidiospores 17.5-23.5 × 16.5-22.5 µm [n = 120, Lm = 20.4, Wm = 19.5, Q = 1.00-1.14, Q = 1.06], globose to subglobose, smooth, colourless, hyaline, thick-walled (up to 1 µm thick). Basidia (Fig. 4b) 65-93 × 20-34 µm, clavate to broadly clavate from a pinched base, 4-spored; thick-walled (up to 1.5 µm thick), sometimes thin-walled; basal clamp connections common; sterigmata 9-14 µm long. Pleurocystidia scattered, 140-230 × 27-42 µm, fusiform, pedicellate, inflated somewhat proximally then extended into a long, broadly cylindrical neck and rounded apex; thick-walled (up to 2 µm thick) colourless, hyaline; basal clamp connections present but rare. Cheilocystidia numerous and forming a sterile edge along the margin of lamellae, 30-100 × 6-36 µm, clavate to broadly clavate, occasionally fusiform, hyaline, colourless, thin-walled, sometimes slightly thick-walled (up to 1 µm thick), basal clamp connections common. Pileipellis an ixotrichoderm, stretched and extensively distorted and irregularly arranged due to the expansion of the pileus, composed of filamentous or fusiform to ellipsoid inflated hyphae, thin – walled, occasionally conspicuously clamped (but usually not so), hyaline.

Habitat: Scattered on fallen trees in rain forests, gregarious or solitary.

Specimens examined: THAILAND, Chiang Mai Prov., Mae Taeng, Ban Mae Sae village, on Hwy 1095 near 50 km marker, N19°14.599’ E98°39.456’, elev. 962 m, rain forest dominated by Castanopsis armata, Castanopsis sp., Pinus sp., Lithocarpus sp. 05 July 2008, J.K. Liu 022 (MFU08 1340), 18 July 2008, J.K. Liu 036 (MFU08 1354), 07 August 2008, J.K. Liu 041 (MFU08 1359).

Distribution: China (Yang et al. 2009); Malaysia (Corner, 1994). New to Thailand.

Notes: All specimens examined were in good condition. Oudemansiella aff. crassifolia, belonging to section Oudemansiella (Yang et al. 2009) can be separated from O. canarii and O. platensis by the absence of the flecks or warts on the pileus. In addition, the structure of pileipellis of O aff. crassifolia is an ixotrichoderm composed of filamentous or fusiform to ellipsoid inflated hyphae and these hyphae appear as loosely interwoven. In O. canarii and O. platensis the pileipellis comprises an erect branched hyphae system. Furthermore, the structure of the pileipellis of O aff. crassifolia does not vary significantly with age unlike in the O. canarii-O. platensis complex (Yang et al. 2009). Most features of our collections are similar to O. crassifolia. However, the spores in our study are smaller than those (21-28 × 19-24 µm) of Corner (1994).


Fig. 1 Basidiocarp of Oudemansiella canarii; b-d. Basidiocarps of Oudemansiella aff. crassifolia; e-f: Basidiocarps of Oudemansiella submucida; g. Basidiocarp of Xerula sinopudens. Scale bars: a = 20 mm; b-d = 10 mm; e-f = 20 mm; g = 30 mm.



Fig. 2 Oudemansiella aff. crassifolia. a: Spores; b: Basidia; c: Pleurocystidia; d: Cheilocystidia. Scale bars: a = 10 µm; b = 20 µm; c, d = 40 µm.



Liu JK, Hyde KD, Zhao RL 2009 Four species of Oudemansiella and Xerula newly recorded from Thailand. Cryptogamie, Mycologie 30: 341–353.




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