Pleocatenata chiangraiensis Y.R. Sun, Yong Wang bis & K.D. Hyde, sp. nov.

MycoBank number: MB 559458; Index Fungorum number: IF 559458; Facesoffungi number: FoF 10631; Figure 2, 3

Etymology. The epithet referring to the location in which the fungus was collected.

Holotype. MFLU 21-xxxx

Description. Parasitic on twigs of Clerodendrum quadriloculare and Tarenna stellulata. Asexual morph: Hyphomycetous. Colonies on natural substrate effuse, dark, velvety. Mycelium immersed, composed of septate, branched, hyaline to subhyaline hyphae. Conidiophores macronematous, mononematous, erect, straight or slightly curved, cylindrical, unbranched, robust, 4–6-septate, brown or dark brown, rough, 35–100 µm long, 5.5–8.5 µm wide. Conidiogenous cells monotretic, integrated, terminal, determinate, cylindrical, dark brown. Conidia catenate, formed in acropetal chains of 2–3, straight or curved, obclavate, olivaceous to brown when young, blackish brown when mature, 5–8-euseptate, slightly constricted at septa, tip conidia rounded at apex, truncate at base, intercalary conidia truncate at both ends, with thickened and darkened scars at base or both ends, 34–70 µm long, 6.5–12 µm at the widest. Sexual morph: Unknown.

Culture characteristics. Conidia germinated on PDA within 12 hours at 25 ºC. Germ tubes were produced from both ends. Colony diameter reached 20–25 mm after 4 weeks at room temperature on PDA media. Mycelia superficial, irregularly circular, entire edge, dark brown from above, black from below, produced pigment which make the media become reddish brown.

Material examined. Thailand, Chiang Rai Province, Mae Fah Luang University, on twigs of Tarenna stellulata, 3 July 2020, Y.R. Sun, MFU5 (MFLU 20-xxxx, holotype, ex-type living culture MFLUCC 20-xxxx). Thailand, Chiang Rai Province, Medicinal Plants Garden, on twigs of Clerodendrum quadriloculare, 7 June 2020, Y.R. Sun, B45 (MFLU 20-xxxx, living culture MFLUCC 20-xxxx).

Notes. Two isolates collected from different hosts share similar morphology and clustered together in the phylogenic tree. There are no base pair differences in LSU and tef1 genes between these two isolates. One base pair and two base pair differences (without gaps) were observed in ITS and rpb2, respectively. Therefore, the two isolates MFLUCC 21-xxxx and MFLUCC 21-xxxx are identified as conspecific.

Figure 2. Pleocatenata chiangraiensis (MFLU 21-XXX, holotype) a Host (Tarenna stellulata) b, c Colonies on natural substrate d, e Conidiophores with conidia f Conidiogenous cells g–k Conidia l Germinated conidium m, n Colonies on PDA. Scale bars: 1 mm (b); 100 μm (c); 20 μm (d–l).

Figure 3. Pleocatenata chiangraiensis (MFLU 21-XXX, other material) a Host (Clerodendrum quadriloculare) b Colonies on natural substrate c, d Conidiophores with conidia e Conidiogenous cells f–j Conidia k Germinated conidium. Scale bars: 200 μm (b); 20 μm (c–k).