Phyllachoraceae Theiss. & P. Syd., Annls mycol. 13(3/4): 168 (1915)
Index Fungorum number: IF 81156; MycoBank number: MB 81156; Facesoffungi number: FoF 01329; 1125 species.
Parasitic on living leaves or saprobic on dead wood submerged in water. Sexual morph: Leaf spots on host black, abundant, scattered, raised, mostly rounded to oblong or elongated, sometimes parallel with leaf venation, surrounded by light brown necrotic region. Ascomata flattened, globose to subglobose, with thin walls, lying in leaf tissues or in a pseudostroma or stroma and maturing in living leaves, ostiolate. Ostiolar canal conical, wide, lacking periphyses. Peridium clypeate, thickest adjacent to ostiolar canal, composed of a deeply melanized, brown-black, amorphous layer of host cuticle and epidermal cells, often merging with a lighter pigmented region of brownish, distorted parenchyma cells infiltrated with fungal hyphae, beneath the clypeus. Lower and lateral peridium composed of two layers; an outer region comprising several layers of dark brown, flattened, thin-walled fungal cells, which internally fuse with several layers of hyaline, flattened, thin-walled fungal cells. Lateral peridium fuses outwardly with an irregular, narrow region of distorted host parenchyma infiltrated by fungal cells. The basal peridium merges outwardly with either a narrow zone of infiltrated and distorted host parenchyma and occasionally lower epidermal cells, or integrates directly with a lower clypeus, similar in construction to that basal peridium. Paraphyses numerous, persistent, filiform, branched or unbranched, septate, slightly longer than asci. Asci 8-spored, persistent, cylindrical to fusiform, short pedicellate, with walls uniform in thickness, not especially thickened at apex, apical ring often present, rarely absent, J-, or J+. Ascospores multi-seriate, fusiform to narrowly oval, usually hyaline, aseptate or rarely septate, often with a mucilaginous sheath, with or without an attenuated base, sometimes with pad-like appendages. Asexual morph: Coelomycetous, with conidia in locules in a stroma, spermatial or disseminative. Conidiomata similar to ascomata, immersed, subcuticular, strongly raising the host surface, occasionally pycnidial, occupying the region between the cuticle and epidermis, ostiolate. Conidiogenous cells arising from the basal and lateral walls, cylindrical, phialidic, aseptate, hyaline, forming conidia singly at the apex. Conidia hyaline, filiform, aseptate (adapted from Maharachchikumbura et al. 2016b).
Type genus – Phyllachora Nitschke
Notes – Theissen & Sydow (1915) introduced Phyllachoraceae, previously placed in several orders, including Dothideales (Horst 1990), Sphaeriales (Nannfeldt 1932, Miller 1951, 1954, Muller & von Arx 1962, Wehmeyer 1975), Xylariales (Luttrell 1951, Barr 1990a), Glomerellales (Chadefaud 1960, Locquin 1984), Phyllachorales (Barr 1976a, b, 1983), Polystigmatales (Eriksson 1982b, Hawksworth et al. 1983), and Diaporthales (Cannon 1988). Currently, it is placed in order Phyllachorales (Maharachchikumbura et al. 2015b, 2016b, Santos et al. 2016, Dayarathne et al. 2017). Phyllachoraceae is characterised by ascohymenial development with paraphyses, thin-walled asci, which may have an apical ring that does not stain blue in iodine (J-) and ascospores that are often hyaline and 1-celled (Cannon 1991). Asexual morphs are coelomycetes, spermatial or disseminative (Hawksworth et al. 1995). Munk (1957) and Barr (1990a) had a different concept of the family, including genera with J+, apical rings, in the ascus. However, in a study based on available molecular data and literature, Maharachchikumbura et al. (2015, 2016b) listed 58 genera in Phyllachoraceae. Mardones et al. (2017) proposed a new family Telimenaceae with Telimena as the type genus, resulting in three families in Phyllachorales and the removal of Telimena from Phyllachoraceae. Dayarathne et al. (2017) excluded Polystigma from the Phyllachorales based on analysis of combined LSU, SSU and ITS sequence data. Hence, at present family, Phyllachoraceae comprises 54 genera. However, sequence data are available only for a few members of the genera Ascovaginospora, Coccodiella and Phyllachora because of the difficulties in obtaining cultures. The family contains a large number of species which are probably host-specific. Most genera are monotypic, and the majority lack sequence data. The family, therefore, needs recollecting with sequence data. Many genera are poorly known, and therefore the notes below are brief.
Genera