Abstract
A new fern species from the Philippines, Haplopteris mindanaoensis S.Linds. & C.W.Chen, is described and illustrated based on the results of detailed morphological comparison and molecular phylogenetic analysis. Morphologically, Haplopteris mindanaoensis is characterised by having obovoid (rather than funnel-shaped) soral paraphyses and deep soral grooves with asymmetrical flaps. Analysis of a combined four gene (chlL, matK, ndhF, and trnL-F) plastid data set shows that: (1) the two included samples of Haplopteris mindanaoensis have the same distinct haplotype; (2) Haplopteris mindanaoensis diverges early within the clade where most species with marginal soral grooves are placed; and (3) Haplopteris heterophylla