Macrohilaceae Crous, IMA Fungus 6(1): 180 (2015)

Index Fungorum number: IF812795; 1 species.

Endophytic or saprobic on leaves of Myrtaceae (dicotyledons). Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata pycnidial, immersed, becoming erumpent, medium brown, globose to irregular. Conidiomata wall composed of pale brown-walled cells of texture globulosa. Conidiophores reduced to conidiogenous cells. Conidiogenous cells pale brown, cylindrical, percurrently proliferating at the apex with annellations. Conidia brown to dark brown, 1-septate, slightly constricted at the septum, apex rounded, base flattened with a protruding hilum (adapted from Maharachchikumbura et al. 2016b).

Type genus – Macrohilum H.J. Swart

Notes – The type species of Macrohilum, M. eucalypti formed a distinct phylogenetic lineage in Diaporthales, thus Crous et al. (2015a) introduced Macrohilaceae to accommodate it. Subsequent publications by Maharachchikumbura et al. (2015, 2016b), Wijayawardene et al. (2016b, 2018a) and Senanayake et al. (2017a, 2018) accepted Macrohilaceae as a well-established family within Diaporthales and basal to Diaporthaceae. Currently, Macrohilaceae comprises only one genus.

Ecological and economic significance of Macrohilaceae
Swart (1988a) reported Macrohilum eucalypti from dead Eucalyptus leaves, while Crous et al. (2015a) isolated M. eucalypti from living leaves. However, neither Swart (1988a) nor Crous et al. (2015a) reported whether it caused leaf spots or any other symptoms. But, both of these publications did not carry out Koch’s postulates to determine the pathogenicity of M. eucalypti. It would be appropriate to carry out more sampling from diseased Eucalyptus leaves and perform Koch’s postulates to determine whether Macrohilum species are pathogens as have been done for Colletotrichum species on Artocarpus heterophyllus (Bhunjun et al. 2019).