Abstract
Multiseptate conidia were observed during an investigation into the effect of light on marine fungi. They were not formed in total darkness and only a few were observed in 12 hr light/12 hr darkness and in continuous light. Conidia were formed on all the 4 media used under black light (one black light fluorescent lamp with a continuous spectrum maximum at 360 nm 18 in above the plates). The highest number of septa/spore was 7, but the degree of septation decreased with time of incubation. The first conidium formed (apical) was usually septate, but those formed subsequently (on lateral denticles) were rarely septate. Conidia were produced most abundantly when grown on corn-meal agar exposed to black light.