The genus Nephrolepis has been placed under the families Davalliaceae and Oleandraceae previously [1]. More recently, it was placed under the family Lomariopsidaceae [2]. There is still no agreement on which family this genus should belongs [1]. I have kept it in the family Nephrolepidaceae for now.
Reference:
1. Christenhusz MJM, Zhang XC, Schneider H. (2011) A linear sequence of extant families and genera of lycophytes and ferns. Phytotaxa 19: 7-54.
2. Brownsey PJ, Perrie LR. (2011) A revised checklist of Fijian ferns and lycophytes. Telopea 13(3) : 513-562.