Colonies initially white or yellowish, mycelium growing rapidly producing a dense layer of erect smooth-stiped, conidiophores terminated by globose vesicles bearing phialides (uniseriate) or metulae with phialides (biseriate) which produce dry chains of conidia. Reverse pale to grayish or greenish yellow. Vesicles radiate, initially pale, becoming dark brown to black. Conidia spherical, mid-to-dark brown, highly roughened with ridges and blunt or pointed protuberances, (3-)4-5(-6) μm in diameter.Sporulation may be inhibited when grown in vessels with reduced gas exchange. Colonies may exhibit sectoring with areas of varying levels of sporulation. Use of freshly produced spores as inoculum should reduce sectoring.