Abstract
A new species, Arthropteris samoensis (Arthropteridaceae), recorded from the Samoan islands of Upolu and Savai‘i, is described and illustrated. In Samoa, the new species is distinguished from Arthropteris palisotii s.l. by its smaller stature and more delicate texture (laminae mostly 4 cm wide); fronds monomorphic with all pinnae distinctly lobed (vs. weakly dimorphic, sterile pinnae with subentire margins and fertile pinnae all lobed; and apices gradually reduced (vs. often with a conform terminal pinna). A molecular phylogeny represented by six chloroplast regions is inferred for 58 samples, with nine of these newly generated for the present study. The sampling design emphasizes Oceania, and a larger representation of the A. palisotii complex, including material from continental Africa. The new species from Samoa is sister to the continental East Asian karst terrain endemic, A. guinanensis , and together they are sister to the broadly defined Arthropteris palisotii complex.