A New Classification of Ficus Subsection Urostigma (Moraceae) Based on Four Nuclear DNA Markers (ITS, ETS, G3pdh, and ncpGS), Morphology and Leaf Anatomy.

Abstract

Ficus subsection Urostigma as currently circumscribed contains 27 species, distributed in Africa, Asia, Australia and the Pacific, and is of key importance to understand the origin and evolution of Ficus and the fig-wasp mutualism. The species of subsection Urostigma are very variable in morphological characters and exhibit a wide range of often partly overlapping distributions, which makes identification often difficult. The systematic classification within and between this subsection and others is problematic, e.g., it is still unclear where to classify F. amplissima and F. rumphii. To clarify the circumscription of subsection Urostigma, a phylogenetic reconstruction based on four nuclear DNA markers (ITS, ETS, G3pdh, and ncpGS) combined with morphology and leaf anatomy is conducted. The phylogenetic tree based on the combined datasets shows that F. madagascariensis, a Madagascan species, is sister to the remainder of subsect. Urostigma. Ficus amplissima and F. rumphii, formerly constituting sect. Leucogyne, appear to be imbedded in subsect. Conosycea. The result of the phylogenetic analysis necessitates nomenclatural adjustments. A new classification of Ficus subsection Urostigma is presented along with the morphological and leaf anatomical apomorphies typical for the clades. Two new species are described ─ one in subsect. Urostigma, the other in Conosycea. One variety is raised to species level.