Colonies on CYA 40-50 mm diam, plane, low and velutinous, usually quite dense; mycelium white; conidial production heavy, brown (Dark Blonde to Camel, 5-6D4); reverse pale to dull brown or yellow brown. Colonies on MEA 40-60 mm diam, similar to those on CYA or less dense. Colonies on G25N 18-22 mm diam, plane or irregularly wrinkled, low and sparse; conidial production light, pale brown; brown soluble pigment sometimes produced; reverse brown. No growth at 5°C. Colonies at 37°C growing very rapidly, 50 mm or more diam, of similar appearance to those on CYA at 25°C.
Conidiophores borne from surface hyphae, stipes 100-250 μm long, smooth walled; vesicles 15-20 μm diam, fertile over the upper hemisphere, with densely packed, short, narrow metulae and phialides, both 5-8 μm long; conidia spherical, very small, 1.8-2.5 μm diam, smooth walled, at maturity borne in long, well defined columns.
Velutinous colonies formed at both 25°C and 37°C, uniformly brown, with no other colouration, and minute conidia borne in long columns make Aspergillus terreus a distinctive species.
Produced by J. Pitt April 1998