Alternaria alternata

Conidia (tretispores) are produced in branching chains.  Characteristically the conidia have an extended apical prolongation.   This is relatively short in saprophytic species like A. alternata but commonly forms a long 'beak' in parasitic species.  This common saprophyte grows in abundance on senescent and dead graminaceous leaves and is one of the species that turns maize leaves almost black in late fall.