From ISTA's Common Laboratory Seed Health Testing Methods for Detecting Fungi:
Growth of the fungus variable. It may consist of a few isolated, dark conidiophores, short to long, bearing clusters of black, shiny conidia at the tips. The growth may be extensive, covering part of seed or whole seed. The conidiophores can also be in small groups (3-4) or in some cases many conidiophores may arise from one point as a compact tuft when only few conidiophores bear 1-2 conidia. The arrangment of conidia on conidiophores is acropleurogenous showing variation: verticils, loose spike, spike.
Conidia smooth-walled, 3-septate, mostly curved, some straight, 3rd cell from the base the largeset and darkest, end cells subhyaline or pale, top cell rounded, basal cell usually with a scar, 19-28 x 7-15μm.
