Arthrinium obovatum M. Wang & L. Cai

Wang, Mei, Tan, Xiao-Ming, Liu, Fang & Cai, Lei, 2018, Eight new Arthrinium species from China, MycoKeys 34, pp. 1-24 : 6-8

Arthrinium obovatum M. Wang & L. Cai sp. nov. Figure 8

Type.

CHINA, Chongqing, on Lithocarpus sp., 20 Dec. 2012, L. Cai, (holotype: HMAS 247184; culture ex-type: CGMCC 3.18331 = LC4940).

Etymology.

Referring to the production of the large obovoid conidia.

Description.

Hyphae hyaline to pale brown, branched, septate, 1.5-5.0 μm diam. Conidiophores reduced to conidiogenous cells. Conidiogenous cells erect, aggregated in clusters on hyphae, pale brown, smooth, subcylindrical or clavate, 5.5-13.5 × 2.5-5.0 μm (x̄ = 8.7 ± 2.4 × 3.6 ± 0.6, n = 30). Conidia dark brown, roughened, globose to subglobose, 11.0-16.5 μm (x̄ = 13.8 ± 1.5, n = 50) in diam.; obovoid, 16.0-31.0 × 9.0-16.0 μm (x̄ = 23.0 ± 2.7 × 12.7 ± 1.4, n = 50), occasionally elongated to ellipsoidal.

Culture characteristics.

On PDA, colonies flat, spreading, margin circular, initially white, becoming olivaceous-grey on surface, reverse smoke-grey with patches of olivaceous grey, reaching 9 cm in 7 days at 25 °C. On MEA, surface olivaceous grey in the central and luteous around, reverse with patches of olivaceous grey.

Other specimens examined.

CHINA, Chongqing, on Lithocarpus sp., 20 Dec. 2012, L. Cai, living culture LC8177; ibid. living culture LC8178.

Notes.

Arthrinium obovatum is the only species that produces obovoid conidia (Figure 8F) in this genus, a character distinctly different from other species ( Ellis 1965, 1976, Gjaerum 1967, Pollack and Benjamin 1969, Hudson et al. 1976, Calvo and Guarro 1980, Khan and Sullia 1980, Samuels et al. 1981, von Arx 1981, Koskela 1983, Kirk 1986, Larrando and Calvo 1990, 1992, Müller 1992, Bhat and Kendrick 1993, Hyde et al. 1998, Jones et al. 2009, Singh et al. 2012, Crous et al. 2013, 2015, Sharma et al. 2014, Senanayake et al. 2015, Senanayake et al. 2015, Hyde et al. 2016, Dai et al. 2016a, b).