Feminine, but usages exist that assume (without explanation) that Phylo is masculine. Most likely named after Phylo, a classical Greek female name in Homer. There are no male personal name usages to be found from that period. Kinberg combined Phylo with the adjective felix, which unfortunately has the same ending whether masculine or feminine, but related names Orbinia and Aricia are also feminine. Unfortunately there are no other historic authors who created original names in Phylo, and it appears that Hartman (1957) subsequently assumed that Phylo was masculine as she changed endings in recombinations to masculine.