Updates on the taxonomic treatment of Frullania serrata (Frullaniaceae) complex in Malaysia

Frullania serrata comprises several infraspecific taxa, but its identifications in Malaysia have hitherto been restricted to the specific level. A Malaysian specimen of Frullania was found in NICH and assigned to F. serrata subsp. grolleana, thereby refining the taxonomic treatment of this species in the country to the subspecific rank. A detailed description, color illustrations, and taxonomic notes based on the Malaysian specimen are provided. This subspecies is distinguished from other infraspecific taxa of F. serrata by the following combination of morphological characters: (1) stem-underleaves with distinctly toothed or dentate margins, (2) elliptical to long-ovate leaves with spreading margins, (3) auriculate and shortly decurrent underleaf bases, and (4) sinuate wall of marginal cells of leaves.