231 NATURE IN SINGAPORE 2009 2: 231–236 Date of Publication: 9 June 2009 © National University of Singapore TUBEROUS, EPIPHYTIC, RUBIACEOUS MYRMECOPHYTES OF SINGAPORE A. F. S. L. Lok 1 and H. T. W. Tan 1* 1 Department of Biological Sciences, National University of Singapore 14 Science Drive 4, Singapore 117543, Republic of Singapore ( * Corresponding author: dbsttw@nus.edu.sg ) INTRODUCTION There are five known genera of tuberous, epiphytic myrmecophytes belonging to the tribe Psychotrieae, subtribe Hydnophytinae of the family Rubiaceae. They are Anthorrhiza, Hydnophytum, Myrmecodia, Myrmephytum and Squamellaria (Huxley & Jebb, 1991). These genera are found in South East Asia to the Pacific islands of Fiji, Vanuatu and Solomon Islands, with the highest diversity in New Guinea. Hydnophytum has the widest distribution, extending from the Andaman Islands, South Thailand, Myanmar, Cambodia, Vietnam, Malaysia, throughout the entire Indonesian Archipelago, the Philippines, Papuasia and its associated islands, the Solomon Islands, Vanuatu, Fiji, and the Cape York Peninsula in Australia (Huxley & Jebb, 1991). Hydnophytum means “truffle plant” and is much more xeromorphic than Myrmecodia, being able to withstand much more desiccating (xeric) conditions (Huxley, 1978). Myrmecodia has the second-widest distribution, with its species are found in Malaysia, throughout the entire Indonesian Archipelago, the Philippines, Papuasia and its associated islands, the Solomon Islands, and the Cape York Peninsula in Australia (Huxley & Jebb, 1993). Myrmecodia means “ant-house”, as their tubers are much more highly specialised and adapted to ant occupation compared to Hydnophytum (Huxley, 1978). Only Hydnophytum formicarum (Fig. 1) and Myrmecodia tuberosa (Fig. 2) were recorded to occur in Singapore. The former is now listed as nationally critically endangered while the later is nationally extinct (Tan et. al., 2008). These species have long been of interest to botanists and ecologists owing to their symbiotic association with ants and these charistmatic plants have recently gained favour with horticulturist-hobbyists because of their bizarre shapes and forms. Fig. 1. Hydnophytum formicarum in cultivation. (Photograph by: Ang Weijen).