Morphology, Anatomy, Micromorphology, and Palynology of the Squirrel’s Foot Fern, Davallia mariesii (Davalliaceae)

Abstract

Davallia mariesii T. Moore ex Baker, a member of the section Trogostolon (Copel.) M. Kato and Tsutsumi (Davalliaceae M.R. Schomb.), is a lithophytic or epiphytic herb that grows on rocks and tree trunks in montane forests. This study analyzed the morphological, anatomical, micromorphological, and palynological characteristics of D. mariesii using a digital slide scanner and a field-emission scanning electron microscope and presented an expanded and updated description. A circumendodermal band was observed in the anatomical structure of the stipe, making D. mariesii the second species in the family Davalliaceae with such a band. The frond anatomical studies revealed that the epidermal cells of the indusium were thicker than those of the epidermis on both sides and that hypostomatic fronds with stomata chambers were present. Diacytic, anisocytic, and tetracytic stomatal complexes were observed on abaxial surfaces. The indusia covered numerous sporangia. Leptosporangium consisted of an apical cap, a basal cap, an annulus, and a stalk. The spore had an ellipsoidal outline, a monolete aperture, and verrucae with colliculate ornamentation. The obtained results provide systematic data for the phylogeny of Davalliaceae and establish a basis for future taxonomic delimitation of other taxa.