Dacryobolus gracilis H.S. Yuan, 2016

Yuan, Hai-Sheng, Kan, Yu-He & Wan, Xian-Zhen, 2016, Two new brown-rot corticioid fungi in Dacryobolus (Basidiomycota) from southwestern China, Phytotaxa 265 (2), pp. 101-111 : 105-106

Dacryobolus gracilis H.S. Yuan , sp. nov. Figs. 3 , 4 .

MycoBank no.: MB810739

Differs from Dacryobolus sudans in having shorter basidia, absence of hymenial cystidia, and absence of viscid liquid on the tip of the aculei.

Holotype: CHINA. Chongqing Municipality, Nanchuang District, Jinfo Mt. , on gymnosperm trunk, alt. 900 m, 19.VII.2014, Yuan 7088 (holotype in IFP).

Gene sequences ex holotype: KM609017 (ITS).

Etymology: Gracilis (Lat.) = thin, referring to slender aculei.

Fruitbody:—Basidiocarps annual, resupinate, effused, closely adnate, fragile and ceraceous, without odour or taste when fresh, rigid upon drying, up to 15 cm long and 5 cm wide. Hymenophore odontioid, aculei conical to cylindrical, solitary, white to cream when fresh, buff to clay-buff upon drying, 4 per mm at the margin and 3–4 per mm in center, aculeal bases 0.2–0.3 mm wide when old, aculei un-forked, up to 1.5 mm long; margin thinning out, white, distinct, minutely fimbriate when juvenile, pale buff and indeterminate with age. Subiculum thin, leathery, cream to pale buff, ca. 0.2 mm.

Hyphal structure:—Hyphal system monomitic; generative hyphae bearing clamp connections, secondary septa present; all hyphae IKI-, CB-; tissues unchange color in KOH.

Subiculum:—Subicular hyphae of two kinds: main hyphae colorless, slightly thick- to thick-walled, moderately branched, straight, 3.5–5 μm diam, occasionally with short tube-like side-branches perpendicular to the main hyphae; tortuous hyphae originate from side-branches of main hyphae, colorless, thick-walled to subsolid, with clamp connections, frequently branched, sinuous as binding hyphae, 2.5–3.5 μm diam, interwoven.

Aculei:—Tramal hyphae colorless, thin- to slightly thick-walled, bearing clamp connections and secondary simple septa, occasionally branched, 2.5–5 μm diam, subparallel. Cystidia present in the central part of the aculei, thin- to slightly thick-walled, with a basal clamp connection, 80–130 × 4.5–5.5 μm; basidia narrowly clavate, with a basal clamp connection and four sterigmata, 19–23 × 2.5–3 μm; basidioles in shape similar to basidia, but slightly smaller.

Spores: — Basidiospores allantoid, colorless, thin-walled, smooth, IKI-, CB-, (4.7–)4.8–5.2(–5.3) × 1–1.2 μm; L = 4.96 μm, W = 1.04 μm, Q = 4.75–4.78 (n= 60/2).

Type of rot:—Brown rot.

Additional specimen (paratype) examined: CHINA. Chongqing Municipality, Nanchuang District, Jinfoshan Mt., on gymnosperm trunk, alt. 800 m, 19.VII.2014, Yuan 7083 (IFP).

Figures

FIGURE 3. A basidiocarp of Dacryobolus gracilis (holotype).

FIGURE 4. Microscopic structures of Dacryobolus gracilis. A: Basidiospores. B: Basidia and basidioles. C: Hyphae from a section of aculei. D: Hyphae from subiculum.