The petioles are dark-purplish, hence the name 'purpurascens' meaning 'becoming purple'. The sporangia are fused in all Ptisana into a bivalvate synangium.
The petioles are dark-violet, hence the name 'purpurascens' meaning 'turning purple'. The sporangia are fused in all Ptisana into a bivalved synangium.