Ctenitis seramensis Holttum. a. Base of a basal pinna showing difference between basal basiscopic and acroscopic pinnules, × 0.6; b. apex of a middle pinna, × 2; c. upper surface of pinna-rachis showing ctenitoid hairs and unicellular glandular hairs between veins, × 20 (a- c:Kato et al. 8031.).