Synonymy of Philippine Ixora (Ixoreae, Rubiaceace) and Ixora silagoensis sp. nov. Cecilia I. Banag, Nicole Marie B. Manalastas and Grecebio Jonathan D. Alejandro C. I. Banag (cibanag@mnl.ust.edu.ph), N. M. B. Manalastas and G. J. D. Alejandro, Dept of Biological Sciences, College of Science, Univ. of Santo Tomas España, Manila 1015, Philippines. CIB and GJDA also at: Research Center for the Natural and Applied Sciences and Graduate School, Univ. of Santo Tomas España, Manila 1015, Philippines. Two endemic Philippine species of Ixora collected in southern Leyte were studied, and investigation of type and other herbarium specimens revealed that one of the species is I. longissima Merr., and that the other does not match any of the known Philippine Ixora species. e recollection of I. longissima after almost a century was essential to investigate whether or not it is conspecific with I. salicifolia DC. is study supports the synonymy of I. longissima and I. salicifolia and provides a full description and illustration of the new species, Ixora silagoensis Manalastas, Banag & Alejandro. e conservation status of I. silagoensis is assessed as ‘Critically Endangered’ (CR) based on the criteria of IUCN. Ixora L. (Ixoreae), is the third largest genus of the family Rubiaceae with ca 530 species ranging from shrubs to small trees (Mouly and Pisivin 2007). Due to the large number of species in the genus, it is presently subject to important investigations and taxonomic changes (Mouly 2007). In the recently circumscribed tribe Ixoreae, Ixora was further enlarged to accommodate several genera including Captaincookia N. Hallé, Doricera Verdc., Hitoa Nadeaud, Myonima Comm. ex Juss., Sideroxyloides Jacq., ouarsiora Homolle ex Arénes, and Versteegia Valeton (Mouly et al. 2009b). Despite some previous and on-going studies on Ixora, the continental Asian, American and Pacific taxa have never been fully revised and no clear picture of their diversity is available (De Block 1998, Mouly 2007, Mouly et al. 2009a, b). According to Merrill (1923), about 42 species of Ixora have been recorded in the Philippines, 32 of which are endemic. is account was updated by Alejandro (2007), identifying 30 Philippine endemic Ixora species out of 41 species. No other studies on Philippine Ixora have been done since then. us, the Ixora species of the Philippines still lack comprehensive descriptions, illustrations and taxo- nomic keys. Information on their distribution, ecology and conservation status is also limited to non-existent. While studying the protologues and examining speci- mens of Ixora for a revision of the Philippine species, several names that needs to be updated came to light. Some collections, on the other hand, could not be matched with known species from the Philippines or neighboring coun- tries and most likely represent new species that need to be described. Among them are the two species collected in Silago and Sogod of the Leyte province. e species collected in Sogod was identified as Ixora longissima Merr., recollected after almost a century since its last collection in 1913. Ixora longissima is endemic to Leyte and was described by Merrill (1910) as closely allied with I. salicifolia (Blume) DC., a non-endemic species of Ixora in the Philippines also found in Indonesia and Malaysia. Both species are characterized by very long leaves. Due to lack of material and published literature on Philippine Ixora, the synonymy of these two species was neither questioned nor investigated. is study is the first attempt to study whether I. longissima and I. salicifolia are the same species and to describe an Ixora species collected in Silago which differ from all other Philippine Ixora species in terms of its inflorescence. Material and methods Taxon sampling is study was based on field observations of two species of Ixora collected in the province of Leyte and examination of herbarium specimens of Ixora from the following herbaria: BR, C, HUH, K, NY, P, PNH, US. Fieldwork were con- ducted in Barangay Catmon, Silago, Leyte and Barangay San Juan, Sogod, and Leyte. Vouchers are deposited at USTH. e herbarium material used for the morphological study of I. salicifolia and I. longissima is listed in Table 1. Preliminary observations on the morphological features of the Ixora species were noted in the field during collection. Further examination of the vegetative and reproductive parts was done on preserved collections using an Olympus Nordic Journal of Botany 32: 761–764, 2014 doi: 10.1111/njb.00411 © 2014 e Authors. Nordic Journal of Botany © 2014 Nordic Society Oikos Subject Editor: John Parnell. Accepted 25 October 2013 761