This name is a synonym.
Pasania cuspidata f. pusilla (Blume) Makino, Bot. Mag. (Tokyo) 23: 142 (1909).
Pasania sieboldii var. pusilla (Blume) Makino, Bot. Mag. (Tokyo) 24: 233 (1910).
Pasaniopsis sieboldii var. pusilla (Blume) Makino, J. Jap. Bot. 5: 19 (1928).
Castanopsis cuspidata f. pusilla (Blume) Nakai, J. Jap. Bot. 15: 263 (1939).