Aureobasidium aerium N. Jiang, sp. nov. FIGURE 2.

MycoBank no: 843527

Etymology: Referring to air where the ex - type strain originated.

Colonies moderately grow on PDA medium, attaining diameter of 30 mm after 7 days of incubation at 25 °C. Colonies are darkly olivaceous, flat, smooth green-yellow and fimbriate margins, often covered in slimy masses of conidia, with no aeriuml mycelium. Hyphae septate, smooth, thin-walled, soon becoming melanized and thick-walled. Conidia 7.3–11.6 × 4–6.9 µm (av. = 8.5 × 5.1 µm), hyaline, aseptate, smooth walled, ellipsoidal to ovoid, variable in size, with rounded to subtruncate base and a flat indistinct hilum. Chlamydospores 12.8–19.5 × 7.9–11.9 µm (av. = 15.3 × 8.7 µm), dark brown, smooth to lightly rough walled, septate to aseptate, globose to ellipsoidal 1- to 2-celled.

Material examined: — CHINA, Beijing, Haidian District, Xiangshan Mountain, from air, H. Xue, 14 April 2015 (holotype CAF 800043 = JNH0039; ex - type culture CFCC 50324); ibid. (culture CFCC 56831).

Notes: — Two isolates from air clustered into a well - supported clade (Fig. 1). Aureobasidium aerium is phylogenetically close to Aureobasidium subglaciale from subglacial ice in sea water; Aureobasidium leucosperm from Leucospermum leaves; Aureobasidium namibiae from dolomitic marble in Namib Desert; and Aureobasidium pini from pine needle surface. However, these five species can be distinguished by the sizes of conidia (12.8 – 19.5 × 7.9 – 11.9 µm in A. aerium vs. 5.5 – 28 × 2 – 6.5 µm in A. subglaciale vs. 8 – 13 × 5 – 9 / 8 – 24 × 2 – 10 µm in A. leucosperm vs. 7 – 17 × 3.5 – 7 µm in A. namibiae vs. 5.1 – 10.5 × 2.5 – 4.8 µm in A. pini) (Zalar et al. 2008; Crous et al. 2011; Jiang et al. 2019).