Pseudolachnella brevifusiformis A. Hashim. & Kaz. Tanaka, sp. nov., MycoBank number: MB 815299

Etymology: named after its resemblance to Pseudolachnella fusiformis, but with smaller conidia.

Saprobic on dead sheath of bamboo. Sexual morph Undetermined. Asexual morph Conidiomata  tromatic, acervular, setose, shallow-cupulate, superficial, globose to oval, up to 295μm high, (325–)450–700(–895) μm diam., scattered to occasionally 2–5 grouped, conical in sectional view; basal stroma 6.5–15μm thick, composed of brown, globose, thick-walled, 2–2.5 μm diam. cells; excipulum 30– 44.5(–50) μm thick, poorly developed, composed of globose, pale brown cells. Setaemarginal, cylindrical, straight to slightly curved, aseptate, brown to dark brown, thick-walled, (315–)380–520 μm long, acute and 2–3.5 μm wide at the apex, 3–4 μm wide at the base. Conidiophores absent. Conidiogenous cells phialidic, cylindrical to lageniform, hyaline, smooth, 6.5–14× 1.5–2.5μm. Conidia (9.5–)10.5–18(–19)× 2–3.5μm (x = 14×2.9μm, n = 78), L/W 3.4–7.6(–8.7) (x =5, n=78), (1–)3-septate, clavate to cylindrical, obtuse at the apex, truncate at the base, hyaline, smooth, bearing (2–)3– 6 unbranched appendages at each end; apical appendage (2.5–)3–6μm long (x =4.3μm, n= 61), central; basal appendage (2.5–)3–5.5(–6.5) μm long (x =4μm, n=61), eccentric.

Material examined: JAPAN, Okinawa, Kunigami, Yona, Mt. Fuenchiji, on dead sheath of Pleioblastus linearis, 19 May 2015, collector K. Tanaka et al., KT 3536 (HHUF 30495, holotype); ex-holotype living culture, MAFF 245411; ibid., KT 3537 (HHUF 30496, paratype); exparatype living culture, MAFF 245412.

Notes: In terms of the similar conidial size and multiple conidial appendages, Pseudolachnella brevifusiformis resembles P. fusiformis, but can be distinguished from the latter by its smaller conidia (vs. 15–20× 4–6.5μm; Hashimoto et al. 2015b). In addition, there were 25 base differences with 12 gaps in their ITS sequence data. Pseudolachnella brevifusiformis was collected from Pleioblastus linearis. Pseudolachnella ryukyuensis was also recorded from same host plant (Hino and Katumoto 1958; Nag Raj 1993). Morphologically, P. brevifusiformis has smaller conidia, as compared with those of the latter (vs. 30– 40 × 2.5–3 μm; Nag Raj 1993).

Fig. 1 Maximum-likehood tree of Pseudolachnella spp. based on analysis of ITS sequence data. Bootstrap values greater than 50 % are presented at the nodes. New taxa are in blue extypes in bold

Fig 2. Pseudolachnella brevifusiformis a, b Appearance of conidiomata on substrate c Conidioma in longitudinal section d Excipulum of conidioma e Conidiomatal setae f, g Conidiogenous cells and immature conidia h–l Conidia m Germinating conidium a–d, i, k, m from HHUF 30495 (holotype); e–h, j, l from HHUF 30496 (paratype).
Scale bars: = 1 mm, = 250 μm, c = 50 μm, d, e = 20 μm, f–h, m = 10 μm, i–l = 5 μm.