New locality and bud growth of the world biggest flower, Rafflesia tuan-mudae, in Naha Jaley, Sarawak, Malaysia

Abstract

A new Rafflesia population was found in Naha Jaley, Sarawak, in 2012. This study aimed to identify this Rafflesia species and investigate its bud growth. First, we described the flower characteristics and compared them with Rafflesia keithii and R. tuan-mudae, which are candidate species for the flower. Also, we investigated the phylogenetic position of this Rafflesia within Rafflesiaceae using DNA analysis. To estimate bud growth curve, we observed bud development from April 2013 to November 2013 in the field. Based on morphological comparisons and phylogenetic analysis, we confirmed the newly discovered population of the Rafflesia at Naha Jaley was R. tuan-mudae, which is the new locality of the species at the most Eastern side of the known distribution for this species. The results indicated that absolute growth rate was greater in larger buds. We also estimated that it took a year to bloom from the initial bud stage. The mortality in one of our sites was very high, with more than 80 % of buds dead prior to flower opening. This flower would be vulnerable to extinction due to their extraordinary characteristics and anthropogenetic effects. Finally, we discussed how Rafflesia populations in Naha Jaley can be conserved both in-situ and ex-situ.