Crepidotus trichocraspedotus T. Bau & Y.P. Ge
MycoBank number: MB830021
Pileus 6.0–19.5mm, semicircular, petaloid to subcircular, convex, light ivory to pastel yellow, slightly viscid, woolly tomentose or not, margin white to whitish, incurved, with obviously radical fibrils, not hygrophanous, with no striate edge. Lamellae 1.5–2.5mm broad, L=11–17, l=3–7, at first white to lemon yellow, saffron yellow to deep orange with age, edge white. Stipe absent or present as white mycelium. Context white, thin. Odour and taste not distinct. Spore print brownish (6D8–6E8). Basidiospores (8.8)9.1–10.5(–10.7) × (5.7–)6.0–6.8(–7.1) μm, Q=1.37–1.60(–1.69) [ x =9.86.5 μm, Qm=1.50], ellipsoid in front view, amygdaliform, inequilateral in side view, yellow-orange to lightrusty, smooth under microscope and SEM. Basidia 10–31 × (5.3–)7.5–10μm, clavate, thin-walled, hyaline, 2- or 4- spored. Pleurocystidia none. Cheilocystidia (36–)49–64(–69) × 3.5–5.4(–7.1) μm, irregular, vine-shaped, apex branched or not, swollen, in lower part diverticulate, thin-walled, hyaline. Pileipellis a trichoderm. Cuticle differentiated into 2 layers, upper layer beneath the pileipellis, consisting of 73–106×2.6–5.3μm interwoven filiform hyphae, lower layer consisting of cylindrical encrusted hyphae, 42–71×6.0–9.8μm. Clamp connections present in all tissues.
Habitat: Scattered on decaying wood.
Additional material examined: CHINA. Yunnan Province: Yi Autonomous Prefecture of Chuxiong, Zi Xi Shan, 12 Aug 2016, Ge, Bau & Yan HMJAU37256 (HMJAU).
Note: Smooth basidiospores and clamped hyphae are common and inconsistent characters in Crepidotus. Several species possess combined characters. C. autochthonus is the most similar species and widely distributed, but differs in vines shape cheilocystidia and encrusted pileipellis (Senn-Irlet 1995; Giovanni & Ledo 2008). Hesler & Smith (1965) described 9 species having smooth ellipsoid basidiospores and lacking clamp connections in sect. Betulae, subg. Dochmiopus. Of which only three species, C. occidentalis Hesler & A.H. Sm., C. antillarum (Pat.) Singer and C. lundellii Pilát, are similar to C. trichocraspedotus, but vine-shaped encrusted pileipellis hyphae are apparently distinguishing characters from the three species. Bandala & Montoya (2000a) revised a selection of American Crepidotus, including Crepidotus citri Pat., C. levisporus Singer, C. sublevisporus Singer, C. yungicola Singer, C. fusisporus Hesler & A.H. Sm. and their five varieties. All the taxa produce tortuous or contorted cheilocystidia. Crepidotus fusisporus can be distinguished from C. trichocraspedotus in having ornamented basidiospores. The remaining four taxa were merged into C. albidus Ellis & Everh. Which possesses smooth basidiospores. Crepidotus albidus differs from C. trichocraspedotus by its smaller basidiospores. Crepidotus exhibits a variety of cheilocystidial shapes, from cylindrical to utriform or flexuous. Giovanni & Ledo (2008) noted the importance of the cheilocystidia in the taxonomy of Crepidotus. The vine-shaped cheilocystidia are apparently unique type in the genus.
Fig. 1 RAxML tree and phylogenetic relationships of Crepidotus. Inocybe species were served as outgroup. Maximum likelihood support values (>50%) and posterior probabilities (>0.80) are showed on main branches (ML/PP).
Fig 2 Microscopic features of Crepidotus trichocraspedotus (HMJAU 37138). a: Basidiomata; b: Basidiospores; c: Basidia; d: Pileipellis; e: Cheilocystidia. Bars: a=10mm; b=5μm; c–e=10μm.