Macrophomina Petr., Annls mycol. 21(3/4): 314 (1923).
Mycelium superficial or immersed, brown to hyaline, branched, septate, often dendroid in culture. Asexual morph: Conidiomata pycnidial, stromatic, separate, globose, dark brown, immersed, unilocular, thick-walled, wall consisting of an outer layer of dark brown thick-walled textura angularis, becoming hyaline towards the inside. Ostiole central, circular, papillate. Conidiophores absent. Conidiogenous cells enteroblastic, phialidic, determinate, discrete, lageniform to doliiform, hyaline, smooth, with wide aperture and minute collarette, formed from the inner cells of the pycnidial wall. Conidia hyaline, aseptate, obtuse at each end, straight, cylindrical to fusiform, thin-walled, smooth, guttulate. Sclerotia black, smooth, hard, formed of dark brown, thick-walled cells. Sexual morph: Unknown (Adapted from Phillips et al. 2013).
Type species: Macrophomina philippinensis Petr.
Notes: Macrophomina was introduced by Petrak (1923) with M. philippinensis as type species. Macrophomina is characterized by pycnidial, stromatic, separate, globose, dark brown conidiomata, enteroblastic, phialidic, determinate conidiogenous cells, hyaline, aseptate, cylindrical to fusiform, thin-walled, smooth conidia. Von Arx (1981) synonymized Macrophomina to Tiarosporella and provided the combination Tiarosporella phaseolina based on the presence of apical mucoid appendages in the conidia. This treatment was not followed by consequent authors except von Arx (1987). Macrophomina resembles Tiarosporella in having apical mucoid appendages but can be differentiated in having percurrently proliferating conidiogenous cells, dark-brown and presence of microsclerotia which is lacking in Tiarosporella species. Holliday and Punithalingam (1988) described the conidiophores of Macrophomina as hyaline phialidic, short obpyriform to cylindrical. Macrophomina phaseolina is also the coelomycete synanamorph of Rhizoctonia bataticola (Phillips et al. 2013). There has been considerable debate regarding the synanamorph, and its taxonomic placement. Crous et al. (2006) induced several strains of M. phaseolina to sporulate on sterile pine needles, reported apical mucoid appendages in the conidia and provided an emended description of the genus. Crous et al. (2006) accepted Macrophomina in Botryosphaeriaceae. Macrophomina is morphologically and phylogenetically a distinct genus in Botryosphaeriaceae. Molecular markers are available for Macrophomina species namely Macrophomina euphorbiicola (ITS, TEF-1, BTUB, Actin, Calmodulin), M. phaseolina (SSU, LSU, ITS, TEF-1, BTUB, mtSSU), M. pseudophaseolina (ITS, TEF-1, BTUB, Actin, Calmodulin) and M. vaccinia (ITS, Actin, TEF-1, BTUB).