Conidiophores erect, terminated by a dense brush-like branching system bearing tapered phialides. The spores (conidia) are colourless, pink, or green and are produced in a dense wet mass from the phialides. The spore-bearing structures can be relatively small as in the two photographs of G. roseum or large and complex as in the drawing of G. viride at right. Similar to Penicillium but with conidia collecting in wet rather than dry masses.

The species occur in soil or decaying plant matter where they frequently are reported as parasites of other fungi. Some can become pests in petri dish cultures, overrunning the colonies of other fungi. Holomorphs: Nectria, Roumegueriella. Refs: Morquer et al., 1963; Raper and Thom, 1949