Clathrospora elynae Rabenh., Hedwigia 1: 116 (1857).

Clathrospora elymae Rabenh. (1857).

Pleospora elynae (Rabenh.) Ces. & De Not., Commentario della Società Crittogamologica Italiana 1 (4): 218 (1863).

Saprobic on wood and stems. Sexual morph: Ascomata 220–140 × 145–175 µm ( = 170 × 150 µm, n = 10), semi-immersed, scattered on the putrid host stems and foliage, subglobose or nearly globose, brown to blackish brown, with a central sunken ostiole open via a circular lid, asci and pseudoparaphyses forming on the base of the peridium. Peridium 20–55 µm ( = 38, n = 20), composed of 3–5 layers of brown, relatively thick-walled cells of textura angularis, inner cells flattened, thin-walled and lighter. Hamathecium composed of dense, 2–3 µm diam ( = 2, n = 20), hyaline, filiform, pseudoparaphyses, longer than the asci. Asci 160–230 × 24–48 µm ( = 190 × 35 µm, n = 20), 8-spored, bitunicate, fissitunicate, thick-walled, cylindrical to clavate, with a short pedicle and minute ocular chamber. Ascospores 40–65 × 18–27 µm ( = 53 × 23 µm, n = 40), biseriate, fusiform, 7-transseptate, two or many rows of longitudinal septa, applanate, muriform, constricted only at the central septum, dark brown to brown, surrounded by a thin, hyaline mucilaginous sheath. Asexual morph: Alternaria-like (Zhang et al. 2012).

 Material examined: SWITZERLAND, on the stem of Carex curvula, September 1898, Winter (BPI 627748, isotype).

Notes: Shoemaker and Babcock (1992) assigned Clathrospora to Diademaceae and included an additional nine species and provided a key to the genus based on the number of septa and length of ascospores. Clathrospora was characterized by circular lid-like opening and applanate, muriform ascospores. Currently, 50 Clathrospora species are listed in the genus in Index Fungorum (2014). Molecular studies based on combine gene analysis showed that two putative strains of Clathrospora, C. elynae (CBS 196.54) and C. diplospora (IMI 68086) clustered in Pleosporaceae (Ariyawansa et al. 2014a). We obtained similar results in the phylogenetic tree produced from combined ITS, nrLSU, nrSSU and RPB2 sequence analysis (Fig. 1). Clathrospora elynae, the type of Clathrospora, formed a separate clade with low bootstrap support (58%) within Pleosporaceae. Based on the phylogenetic result together with the morphological characters (slightly papillate ostiole with applanate, muriform ascospores and Alternaria- like asexual morph) we refer Clathrospora to Pleosporaceae.

Fig 1. Clathrospora elynae (isotype) a. Herbarium material. b. Close up of ascomata. c. Section of the ascomata d. Close up of the peridium. e. Hyaline, filiform, pseudoparaphyses. f-h. Cylindrical to clavate asci with a short pedicle and ocular chamber. i-k. Dark brown to brown muriform ascospores surrounded by a thin, hyaline mucilaginous sheath. Scale bars: b = 100 µm, c = 10 µm, d-g = 60 µm, h-j= 30 µm