Leptographium pseudoalbum M.L. Yin, Z.W. de Beer and M.J. Wingf.

Yin, Mingliang, Wingfield, Michael J., Zhou, Xudong, Linnakoski, Riikka & Beer, Z. Wilhelm de, 2019, Taxonomy and phylogeny of the Leptographium olivaceum complex (Ophiostomatales, Ascomycota), including descriptions of six new species from China and Europe, MycoKeys 60, pp. 93-123 : 93

Leptographium pseudoalbum M.L. Yin, Z.W. de Beer and M.J. Wingf. sp. nov. Fig. 5

Etymology.

The epithet refers to the previous, incorrect identification of the ex-holotype isolate of this species as Graphium album .

Type.

SWEDEN, from Pinus sylvestris infested by Tomicus piniperda , 1953, Mathiesen-Käärik, (PREM 61050- holotype, ex-holotype cultures: CBS 276.54 = CMW 40671 = JCMW 9774 = C 1225).

Description.

Sexual state not observed. Conidiophores macronematous, synnematous, 120-270 μm including conidiogenous apparatus, synnemata frequently swollen at base, frequently wider at stipe, expanding branches at apex, brown to hyaline, (11 –)25–34(– 40) μm in width. Conidiogenous cells discrete, terminal, percurrent and phialidic proliferation, hyaline, cylindrical, (9 –)10–14(– 18) × 1.8-2.8 μm. Conidia hyaline, one-celled, ellipsoidal to cylindrical, (3.5 –)4.3–5.2(– 6.5) × 2.4-3.3 μm. Cultural characteristics: Colonies on OA, hyaline at first, later becoming white and gray in the center, hyphae hyaline, appressed and immersed, aerial mycelium frequently present on wood tissue, phialographium-like asexual morph abundant. Optimal growth temperature on MEA:25 °C with radial growth rate 3.0 ( ± 0.5) mm/d, while growth slightly reduced at 10 °C and 30 °C, and no growth occurred at 35 °C.

Host.

Pinus sylvestris .

Insect vector.

Tomicus piniperda .

Distribution.

Sweden.

Notes.

This species was initially identified as Graphium album (Corda) Sacc. by Mathiesen-Käärik (1953). However, Okada et al. (2000) and Harrington et al. (2001) questioned the identification by Mathiesen-Käärik (1953) and showed that this isolate belonged in the Ophiostomatales and grouped close to L. erubescens . This study showed that Mathiesen-Käärik’s isolate representing an undescribed species in the L. olivaceum complex, for which we have provided the name L. pseudoalbum .

Figures

Figure 5. Leptographium pseudoalbum sp. nov. (CBS 276.54) a fourteen-days old culture on OA with black background; b. synnematous asexual state on wood tissue on WA c-d conidiophore e conidiogenous cells f conidia. Scale bars: 200 μm (b), 25 μm (c), 25 μm (d), 10 μm (e), 5 μm (f).