The development of the epibiotic sporangium from resting spore zoospores of 18 Physoderma spp. has been examined to determine whether or not this stage can assist in delimiting groups of species within the genus when associated with other morphological characters. It was found that 11 entities had a "bilateral" type of sporangial development and 7 had a "unilateral" type. These types could not be associated with other morphological features of either epibiotic or endobiotic stages to produce taxonomic groupings. Type of epibiotic sporangial development, at the moment, is regarded as simply another morphological parameter.