Heterobasidion amyloideopsis, Zhao & Saba & Khalid & Song & Pfister, 2017

Zhao, Chang-Lin, Saba, Malka, Khalid, Abdul Nasir, Song, Jie & Pfister, Donald H., 2017, Heterobasidion amyloideopsis sp. nov. (Basidiomycota, Russulales) evidenced by morphological characteristics and phylogenetic analysis, Phytotaxa 317 (3), pp. 199-210 : 206-207

Heterobasidion amyloideopsis M. Saba, C.L. Zhao, Khalid & Pfister, sp. nov. ( Figs. 4 , 5 )

MycoBank no.: MB 821895

Diagnosis: —Basidiomata annual, pileate. Pileal surface rust, margin white, blunt. Hyphal system dimitic; generative hyphae simple septate in trama and clamp connections present in context; contextual skeletal hyphae amyloid. Basidiospores broadly ellipsoid, hyaline, fairly thick-walled, asperulate, IKI–, CB+.

Type:— PAKISTAN. Khyber Pakhtoonkhwa: Mansehra, Chattar Plain, elev. 520 m, on stump of Pinus wallichiana A. B. Jacks. , 22 November 2013, Malka Saba 8848 (holotype, FH!).

Etymology:— amyloideopsis (Lat.) : referring to the similarity to Heterobasidion amyloideum .

Basidiomata annual, pileate, usually imbricate, leathery and without odor or taste when fresh, becoming woody and hard upon drying. Pileus semicircular to fan-shaped, projecting up to 3 cm, 6 cm wide, and 1 cm thick at base. Pileal surface rust when young, becoming deep rust to dark brown with age, crustose, azonate; margin white, blunt. Pore surface white when fresh, pinkish buff when dry, not shiny; pores round, 2–4 per mm; dissepiments thin, entire. Context white to cream, woody hard when dry, azonate, homogeneous up to 4 mm thick, without a thin black line under the pileus surface. Tubes cream, hard and corky, up to 6 mm long.

Hyphal structure dimitic; simple septate generative hyphae in trama, clamp connections present in contextual generative hyphae; tramal skeletal hyphae dextrinoid, CB+; contextual skeletal hyphae IKI+, CB+, hyphae unchanged in KOH (not dissolving).

Context generative hyphae frequently present, hyaline, thick-walled, with a wide lumen, occasional clamp connections and branching, 3.5–6 μm in diameter; skeletal hyphae dominant, hyaline, thick-walled with a wide to narrow lumen, unbranched, regularly arranged, 4.5–7 μm in diameter. Hyphae at crust mostly hyaline, thick-walled with distinct lumens.

Tube trama generative hyphae occasionally seen, hyaline, thin-walled, simple septate and unbranched, 3–5 μm in diam; skeletal hyphae dominant, hyaline, thick-walled with a wide to narrow lumen, unbranched, approximately parallel, 4–6 μm in diam. Cystidia not seen, but fusoid cystidioles present, hyaline, thin-walled, 10–12 × 2–3 μm; basidia short clavate to barrel-shaped, with a simple basal septum and four sterigmata, 13–15 × 5–6 μm; basidioles dominant, similar to basidia, but slightly smaller.

Basidiospores broadly ellipsoid, hyaline, fairly thick-walled, asperulate, IKI–, CB+, (4.7–)4.9–6.2(–6.6) × (3.7–) 4–5.2(–5.4) μm, L = 5.6 μm, W = 4.6 μm, Q = 1.18–1.24 (n = 60/2).

Additional specimen examined: — PAKISTAN. Khyber Pakhtoonkhwa: Mansehra, Chattar Plain, elev. 520 m, on stump of Pinus wallichiana , 22 November 2013, Malka Saba 118 (LAH!)

Figures

FIGURE 4. Basidioma of Heterobasidion amyloideopsis (holotype). Scale bars: 2 cm.

FIGURE 5. Microscopic structures of Heterobasidion amyloideopsis (drawn from the holotype).a.basidiospores.b.basidia and basidioles. c. cystidioles. d. hyphae from trama. e. hyphae from context. Bars: a–5 μm; b–e–10 μm.