A New Record Of Pyrostria (Vanguerieae-Rubiaceae) From The Philippines Inferred from Molecular and Morphological Data

Abstract

Recent studies on Canthium revealed that the genus is polyphyletic. Subsequently, Canthium sensu stricto ( s.s. ) was re-delimited to species having paired supra-axillary spines, which led to the reinstatement of various genera in the Vanguerieae such as Keetia, Psydrax and Pyrostria . This raised questions on the generic affiliations of Philippine Canthium species as most of its members lacked spines. In an effort to revise the Philippine Canthium , the endemic spineless Canthium subsessilifolium was collected to ascertain its generic affiliation within the tribe using plastid ( trnL-F region) and nuclear (ITS region) markers. The majority-rule consensus tree of combined data sets showed a wellsupported clade of the whole Vanguerieae (PP=1.00). Interestingly, C. subsessilifolium was nested within the robustly supported Pyrostria clade (PP=1.00). Morphological similarities of C. subsessilifolium with Pyrostria further supported our molecular results. Therefore, a new combination is here provided: Pyrostria subsessilifolia (Merr.) Arriola & Alejandro. This study establishes for the first time the existence of Pyrostria in the Philippines. Keywords : Canthium; ITS; Pyrostria; Rubiaceae; trnL-F; Vanguerieae