Tryon (1970) revised the classification of the family Cyatheaceae and recognized six genera and three principal evolutionary lines among the squamate genera. Sphaeropteris with its undifferentiated (conform) scales represents an evolutionary line and occurs at the base of the squamate genera, while Cnemidaria with its marginate scales is found at the top of another evolutionary line. Sphaeropteris supposably contains elements allied to the other two major evolutionary groups in the family (Tryon & Tryon, 1982). On the basis of scale characters, Sphaeropteris subgenus Sphaeropteris is related to Alsophila and subgenus Sclephropteris is allied with Trichipteris, Cyathea and Cnemidaria. Holttum and Edwards (1983) believe that this latter alliance (together with certain species of Tryon's Sphaeropteris) forms a natural group which needs a new subdivision. Holttum (1963, 1964, 1965) also has intensively studied the Cyatheaceae, but recognized only a single genus Cyathea for the same taxa in the family. He subdivided the genus on the basis of characters of the stipe scales and associated characters of indusia, hairs and venation, and felt that the only sharp subdivision within the genus is between the subgenus Sphaeropteris and the subgenus Cyathea (Holttum, 1982; Holttum & Edwards, 1983). His subgenus Sphaeropteris is characterized by peculiar marginal setae on the stipe scales and certain indusial and venation characters, while Tryon (1970) regarded the uniformity of cells of the stipe scales as the most important character for delimiting the genus Sphaeropteris. Although Tryon (1970) promoted subgenus Sphaeropteris to generic rank, Holttum & Edwards (1983) feel that it is not a natural group and contains species that do not belong in the group. Sphaeropteris sensu Tryon is a genus of approximately 120 species found in both the New and Old World. Its distinctive feature is the presence of conform stipe scales with undifferentiated or poorly differentiated cellular construction