Hymenochaete fissurata S.H. He & Hai J. Li, 2012

He, Shuang-Hui & Li, Hai-Jiao, 2012, Hymenochaete (Hymenochaetales, Basidiomycota) in China. 6. H. fissurata sp. nov. from Yunnan and Sichuan Provinces, Phytotaxa 73 (1), pp. 31-36 : 32-34

Hymenochaete fissurata S.H. He & Hai J. Li , sp. nov. ( Figs. 1 , 2 )

MycoBank no.: MB 801312

Carpophorum annuum, effusum, adnatum. Hymenophorum laeve, rimosum. Tomentum, cortex et stratum hypharum adsunt. Systema hypharum monomiticum, hyphae generativae septatae, efibulatae. Setae numerosae, subulatae, acutae, (25–)30–60(–65) × (4.5–)5–8(–9) µm. Sporae ellipsoideae vel ovoideae, IKI–, CB–, (3.5–)3.6–5(–5.2) × (2–)2.1–2.8(–3) µm.

Type.— CHINA. Yunnan Prov.: Shangri-La County, Pudacuo Forest Park, alt. 3600 m, on fallen trunk of Rhododendron , 24 September 2011, He 1193 (holotype, BJFC!) .

Etymology.— fissurata (Lat.) refers to the densely cracked hymenophore surface.

Fruitbody. —Basidiocarps annual, effused or effused-reflexed with slightly elevated margins, adnate, woody hard and brittle when dry, first as small colonies, later confluent up to 20 cm or more in the longest dimension, 180–800 µm thick in section. Hymenophore smooth or with some scattered tubercles, pale mousegray, ash-gray to vinaceous gray, irregularly and deeply cracked with edges lifting to expose the substratum when mature; margin thinning out, distinct, cinnamon to yellowish brown when juvenile, becoming indistinct, concolorous and slightly elevated when mature.

Hyphal structure.— Hyphal system monomitic; generative hyphae without clamp connections; tissue darkening but otherwise unchanged in KOH.

Subiculum. —Tomentum, cortex (with dark line) and hyphal layer present. Cortex composed of strongly agglutinated hyphae, thickening with age, 15–80 µm. Setal hyphae (embedded setae) occasionally present, longer and narrower than hymenial setae. Generative hyphae colorless to yellowish brown, thin- to thickwalled, septate, moderately branched, more or less regularly arranged, compacted and cemented, 2–3 µm in diam.

Hymenium. —Hyphae similar to those in subiculum, yellowish brown, thick-walled, agglutinated, 2–2.5 µm in diam. New hymenium grown over the old ones with most setae embedded. Setal layer thickening, composed of one to several rows of overlapping setae. Setae numerous, subulate, reddish brown, some enmeshed with a thin hyphal sheath, smooth, with acute tips, projecting up to 30 µm above the hymenium, (25–)30–60(–65) × (4.5–)5–8(–9) µm. Cystidia absent, simple hyphidia present, not numerous. Basidia clavate, with four sterigmata and a simple septum at base, 10–15 × 3–3.5 µm; basidioles in shape similar to basidia, but smaller.

Spores.— Basidiospores ellipsoid to ovoid, hyaline, thin-walled, smooth, IKI–, CB–, (3.5–)3.6–5(–5.2) × (2–)2.1–2.8(–3) µm, L = 4.2 µm, W = 2.5 µm, Q = 1.6–1.7 (n = 60/2).

Additional specimens examined.— Hymenochaete fissurata : CHINA. Yunnan Prov.: Lanping County, Changyanshan, on fallen trunk of Rhododendron , 18 September 2011, He1117; Shangri-La County, Pudacuo Forest Park, alt. 3600 m, on fallen trunk of Rhododendron , 24 September 2011, He 1202; Sichuan Prov.: Songpan County, Huanglong Forest Park, alt. 3400 m, on fallen trunk of Rhododendron , 14 September 2012, He 1357; Puge County, Luojishan Forest Park, alt. 3600 m, on dead Rhododendron tree, 19 September 2012, Dai 12978 (paratypes, BJFC!). H. stratura G. Cunn. (1957: 37) : NEW ZEALAND. Taranaki, Mt. Egmont, Dawson Falls, on bark of dead branches of Podocarpus hallii , January 1953, J.M. Dingley (holotype, PDD 12463!); Auckland, Waipoua Kauri Forest, on dead branch of Podocarpus totara , 20 January 1955, J.M. Dingley (paratype, PDD 16626!).

Remarks.— Hymenochaete fissurata is characterized by its hard and densely cracked basidiocarps, presence of a distinct cortex and hyphal layer (in section Hymenochaete ), compacted and cemented hyphae, relatively short setae, and small basidiospores.

Microscopically, the new species is very similar to H. stratura which also has a hyphal layer composed of densely compacted and cemented parallel hyphae, short setae and small basidiospores ( Cunningham 1957). However, the latter species differs in having coriaceous and more brittle basidiocarps, no cortex in cross section, and is found in New Zealand ( Cunningham 1957). Two other species, H. dura Berk. & M.A. Curtis (1868: 334) and H. sordida Speg. (1926: 139) resemble H. fissurata by sharing similar short setae and small basidiospores. While H. dura differs in having basidiocarps without cracks, bifurcate hyphidia and a distribution in the neotropics ( Burt 1918, Cunningham 1957, Escobar 1978, Léger 1998), H. sordida is distinct from H. fissurata by having a weakly developed cortex and numerous conglomerates of crystals in the stratified hymenium and hyphal layer ( Léger 1998, Parmasto 2006). Hymenochaete fissurata is somewhat similar to H. adusta ( Léveillé (1844: 213) Har. & Pat. (1903: 7), which also has woody hard basidiocarps and relatively short setae and small basidiospores. However, the latter species has pileate basidiocarps, both shorter setae and basidiospores, and no cortex ( Léger 1998).

Figures

FIGURE 1. Basidiocarps of Hymenochaete fissurata (the holotype).

FIGURE 2. Microscopic structures of Hymenochaete fissurata (drawn from the holotype by Hai-Jiao Li). a. Basidiospores. b. Basidia and basidioles. c. Setae. d. Hyphae from the hyphal layer.