Dimorphiseta obtusa J.M. Liang, G.S. Li & L. Cai

Liang, Junmin, Li, Guangshuo, Zhou, Shiyue, Zhao, Meiqi & Cai, Lei, 2019, Myrothecium-like new species from turfgrasses and associated rhizosphere, MycoKeys 51, pp. 29-53 : 29

Dimorphiseta obtusa J.M. Liang, G.S. Li & L. Cai sp. nov. Fig. 3

Type.

China, Beijing, isolated from rhizosphere soils of P. pratensis , 23 Jun 2017, J.M. Liang, holotype HMAS 247954, ex-holotype culture CGMCC3.19206 = LC12128.

Description.

Colonies on PDA, OA and CMA approx. 5-6 cm diam. after 7 d at room temperature (approx. 25 °C), mycelium white and abundant, with conidiophores forming on the aerial mycelium, carrying slimy olivaceous green to black conidial masses, reverse on PDA pale luteous to buff. Conidiomata sporodochial, stromatic, superficial, scattered, rarely gregarious, oval to elongate or irregular in outline, 60-280 µm diam., 40-120 µm deep, with a setose fringe surrounding green to black slimy mass of conidia. Stroma poorly developed, hyaline, smooth to verrucose, of textura angularis. Setae arising from the basal stroma, thin-walled, 3-6-septate, unbranched, hyaline, smooth, 80-250 µm long, 2-4 µm wide at the broadest, terminating in a blunt apex. Conidiophores macronematous, irregularly, unbranched, smooth to lightly verrucose, arising from the basal stroma, up to 18 μm long. Conidiogenous cells phialidic, hyaline, smooth to verrucose, cylindrical, 7-19 × 2-3 μm, becoming narrowed at the tip with collarette. Conidia aseptate, ellipsoidal or cylindrical, hyaline, smooth, rounded both ends, with a funnel-shaped apical appendage, 9-11 × 2-4 μm (av. 10 ± 0.5 × 3 ± 0.3 μm, n = 50).

Distribution.

China.

Etymology.

Named refers the setae with obtuse apices.

Additional isolates examined.

China, Beijing, from rhizosphere soils of Agrostis stolonifera , 24 Jul 2017, J.M. Liang, LC12129; China, Beijing, from rhizosphere soils of P. pratensis , 25 Aug 2017, J.M. Liang & G.S. Li, LC12130, 19 Jul 2017, J.M. Liang, LC12133; China, Beijing, from rhizosphere soils of Poa sp., 19 Jul 2017, J.M. Liang, LC12131; China, Beijing, from rhizosphere soils of Festuca arundinacea , 19 Jul 2017, J.M. Liang, LC12132; China, Beijing, from leaves of P. pratensis , 23 Jun 2017, J.M. Liang, LC12134, LC12135.

Notes.

Dimorphiseta obtusa formed a highly supported cluster with D. terrestris and D. acuta , but can be distinguished from the latter two by having setae with erect and obtuse apices. In addition, D. obtusa is also morphologically similar to two old un-sequenced Myrothecium taxa, i.e. M. biforme and M. dimorphum , but both of these two taxa have two types of conidia. Myrothecium biforme produces short cylindrical and ellipsoidal to navicular conidia ( Jiang et al. 2014) and M. dimorphum has ovate and ellipsoidal conidia ( Watanabe et al. 2003).