Xeromphalina utricularis T. Bau & L N. Liu, 2018

Liu, Li-Na & Bau, Tolgor, 2018, Two new Xeromphalina (Mycenaceae, Agaricales) species with eccentric stipes from subtropical China, Phytotaxa 379 (4), pp. 277-286 : 282-284

Xeromphalina utricularis T. Bau & L N. Liu sp. nov. ( Figure 4 , 5 )

Mycobank No. MB828078

Diagnosis:—Pileus convex to plano-convex with umbilicate centre, light brownish yellow to yellow-brown pileus, decurrent lamellae, light brownish yellow to yellow-brown, eccentric or lateral stipe, basidiospores cylindrical, basidia 4 or 2–spored, cheilocystidia utriform or broadly fusoid, pleurocystidia absent, pileipellis turns orange-brown in KOH, subpileipellis turns light brownish yellow to brown in KOH, circumcystidia and caulocystidia utriform, clavate or fusoid, irregular to subcoralloid.

Etymology:—referring to the utriform cystidia.

Type:— CHINA. Tibet, Nyingchi city, Bayi town, Mountain than day national forest park, 29°39′10″ N, 94°22′27″ E, 2 August 2018, Lina Liu, Voucher : HMJAU47883 (Holotype!).

Description:— Pileus 4–11 mm in diam., convex with defined eccentric umbilicate centre with revolute margin when young, expanding to plano-convex when old, slightly hygrophanous, slightly translucent-striate at margin, light brownish yellow (5D7) to yellow-brown (5D8), glabrous, darker and becoming rugose when dry. Lamellae decurrent with few lamellulae, crowded (L=25–34, I=1–2), sometimes anastomosed, narrow, greyish yellow (4A5) to grey (4C5), margins even. Stipe 4–9 × 0.6–1.2 mm, eccentric or sublateral, almost cylindrical, somewhat broader at base, light brownish yellow (5D7) to yellow-brown (5D7), entirely pubescent, with concolorous to concolorous brown basal tomentum. Context pale yellow (4A2). Smell and Taste indistinct. Rhizomorphs absent.

Basidiospores 4.1–5.2 × 1.6–2.0 μm, Q = 2.3–2.8, amyloid, cylindrical, hyaline to pale brown, thin-walled, smooth. Basidia 17–20 × 3–4 μm, 4 or 2 spored, narrowly clavate to subcylindrical. Lamellar edge heterogeneous, composed of abundant scattered cheilocystidia mixed with basidia and basidioles. Cheilocystidia frequent, 22–29 × 7–10 μm, utriform or broadly fusoid, without mucronate apex, thin-walled, hyaline. Pleurocystidia not seen. Pileitrama made up of cylindrical, sometimes inflated thin- to slightly thick-walled, 4–8 μm wide hyphae, smooth or encrusted with brownish pigment which turns orange-brown in KOH. Pileipellis a cutis, made of subparallel, cylindrical or inflated with constricted septa, slightly thick-walled, 5–10 μm wide hyphae, sometimes incrusted, with yellowish brown parietal pigment which turns orange-brown in KOH. Subpileipellis made up of parallel, 3–6 μm wide hyphae, with encrusting yellowish brown pigment, which turns light brownish yellow to brown in KOH. Pileocystidia abundant, 20–37 × 3–7 μm, utriform, clavate or fusoid, sometimes with one branch at apex, irregular to subcoralloid, thick-walled, orange-yellow-brown in KOH. Stipitipellis a cutis of parallel, cylindrical, thick-walled hyphae, with pale yellow or brown parietal pigment which turns orange-brown or light brownish yellow in KOH. Caulocystidia very numerous, 22–29 × 4–7 μm, utriform, clavate or fusoid, sometimes with one branch at apex, irregular to subcoralloid, thick-walled, orange-brown or light brownish yellow in KOH. Clamp-connections present.

Habitat: Saprophytic; scattered or gregarious on decaying wood of Pinus densata Mast. covered with mosses and lichen.

Known distribution: Tibet, China.

Additional material examined: CHINA. Tibet, Nyingchi city, Sejira national forest park, 29°33′47″ N, 94°32′10″ E, 3 August 2018, Lina Liu, Voucher : HMJAU47897.

Figures

FIGURE 4. Basidiomata of Xeromphalina utricularis. Scale bar=5 mm; a, b, c. HMJAU47883; d, e. HMJAU47897. Photos by: Lina Liu.

FIGURE 5. Features of Xeromphalina utricularis. a. Basidiomata; b. Basidia; c. Basidiospores; d.Cheilocystidia; e. Elements of pileipellis; f. Elements of stipitipellis. Scale bars a=5 mm; c=5 μm; b, d, e, f =10 μm. All drawings from holotype. Drawings by: Lina Liu.