A natural hybrid of the carnivorous plant <i>Nepenthes benstonei</i> × <i>rafflesiana</i> (Nepenthaceae) emits vivid green autofluorescence: the first report for the genus

Abstract While blue fluorescence has previously been reported in several genera of carnivorous plants, green fluorescence has not been formally documented in previous literature. Here, we present the first confirmed record and qualitative documentation of vivid green biofluorescence in a member of the genus Nepenthes (Nepenthaceae). This study aims to examine this distinctive trait and interpret its ecological and taxonomic implications. The specimens exhibited intermediate morphological characteristics—including leaf margins lined with brown hairs, distinctly petiolated leaves, and a peristome bearing spike-like teeth—indicating a hybrid origin between two sympatric species, N. benstonei and N. rafflesiana . Under UV light (365 nm excitation), the peristomes of mature pitchers from the Nepenthes hybrid ( N . benstonei × rafflesiana ) exhibited intense green fluorescence. In contrast, both putative parental species emitted blue fluorescence: N. benstonei uniformly across its peristome, while N. rafflesiana displayed sparse yellow-green streaks on its peristome. The natural hybrid was discovered at elevations of 700–900 metres above sea level (MASL) in the Timur Range, Peninsular Malaysia, with only nine individuals recorded. In addition to providing preliminary data on the occurrence of an undescribed taxon, this represents the first recorded instance of green autofluorescence in Nepenthes —hitherto unobserved in the wild—that may contribute to its insect-luring strategy. Our findings underscore the rich biodiversity of the region’s rainforests and highlight the urgent need for conservation efforts to safeguard these ecosystems, which may harbour as-yet-undiscovered taxa.