A checklist of Rubiaceae species from Eastern Samar, Visayas, Philippines

Abstract

Samar Island is a center of botanical wealth throughout the Philippine archipelago. However, floristic knowledge of the island is deficient and most of its forested areas remain largely unexplored. Thus, floristic surveys of Rubiaceae members were made on Eastern Samar, located in Visayas, Philippines. Collections were conducted from June 2013 to June 2017 within 5 municipalities: Borongan, Balangkayan, Taft, Guiuan, and Llorente. In total, 59 species belonging to 31 genera representing 21 tribes of the family were recorded. The most species-rich tribes belong to Naucleeae, Psychotrieae, and Spermacoceae, with 10, 8, and 6 species, respectively. Of the 59 species recorded, 37 are endemic to the Philippines. Twelve species are listed as threatened species based on its proposed IUCN category and DAO 2017-11. This study presents an enumeration of Rubiaceae found on selected forested areas of Eastern Samar, Philippines.