A contribution to the systematics of Xylopia (Annonaceae) in the New Guinea region

In the New Guinea region, including the Solomon Islands and Halmahera, three species of the pantropical genus Xylopia L. have been previously recognised: X. calosericea Diels, X. papuana Diels, and X. peekelii Diels. In recent floristic tabulations the genus has thus comprised a minor component of the Annonaceae flora. Here we present descriptions and illustrations of 14 new species of the genus from the region: Xylopia aenea D.M.Johnson & N.A.Murray, X. ampla D.M.Johnson & N.A.Murray, X. brunneola D.M.Johnson & N.A.Murray, X. bullata D.M.Johnson & N.A.Murray, X. chlorosperma D.M.Johnson & N.A.Murray, X. cornuta D.M.Johnson & N.A.Murray, X. corrugata D.M.Johnson & N.A.Murray, X. makiraensis D.M.Johnson & N.A.Murray, X. musella D.M.Johnson & N.A.Murray, X. pachysericea D.M.Johnson & N.A.Murray, X. rogstadii D.M.Johnson & N.A.Murray, X. sulangwane D.M.Johnson & N.A.Murray, X. takeuchii D.M.Johnson & N.A.Murray, and X. vulcanicola D.M.Johnson & N.A.Murray. We distinguish the 17 species in a diagnostic key. The region includes Xylopia species that are among the tallest in this genus of c. 220 species, one with the largest leaves and another with the largest fruit, as well as several species with distinctive cataphyll-covered resting buds. The genus has undergone multiple dispersals both to and within the region, with higher diversity on smaller islands than on New Guinea. Its presence on oceanic islands indicates over-water dispersal.