A checklist of all species of bryophytes, lycophytes, ferns, gymnosperms and angiosperms that are found in the wild (native, naturalised and casual) in Singapore is presented. We have attempted to account for all names of species and infraspecific taxa that have ever been recorded for Singapore, along with the pertinent publications that reported each of these names. For each currently accepted name, the synonyms of relevance for Singapore are included. The native or non-native status for all taxa is given, along with the most recent national conservation assessment applied to each native taxon. If we were aware that the most recent assessment required an update, the taxon is newly assessed here. The checklist includes 2654 native taxa, 479 naturalised/casual taxa and 101 cryptogenic taxa.

The paleotropical monocot Pandanaceae family comprises c. 700 species distributed into five genera: Benstonea (c. 60 spp.), Freycinetia (c. 250 spp.), Martellidendron (6 spp.), Pandanus (c. 450 spp.) and Sararanga (2 spp.). Benstonea was circumscribed to include species previously placed in Pandanus section Acrostigma (one of the four sections of Pandanus subgenus Acrostigma). New phylogenetic data show that the six species of the remaining three sections of subgenus Acrostigma (sections Epiphytica, Fusiforma and Platystigma) and a seventh species doubtfully placed in section Acrostigma (Pandanus microglottis) also belonged to Benstonea. This genus is therefore characterized by a suite of morphological characters, viz. stigmatic groove on the adaxial side of the stigma and a staminate flower reduced to 1 to 3 free stamens (sometimes joined at base). We therefore make here the necessary seven new combinations accompanied by one lectotypification in Benstonea, a genus that now reflects the view of the visionary Benjamin Stone who had already grouped these species in Pandanus subgenus Acrostigma based solely on morphology.

Abstract

Pandanaceae, a palaeotropical monocot family of c. 700 species, comprises four currently recognized genera: Freycinetia Gaudich., Martellidendron (Pic. Serm.) Callm. & Chassot, Pandanus Parkinson and Sararanga Helms. Within Pandanus (c. 500 spp.), species of sect. Acrostigma Kurz [one of four sections comprising subg. Acrostigma (Kurz) B. C. Stone] possess highly distinctive morphological features (viz. sharp spiniform, linear styles with the stigmatic groove on the abaxial side of the style and a staminate flower reduced to 1 to 3 stamens) shared with two other species (likewise belonging to subg. Acrostigma but originally placed in sect. Fusiforma B. C. Stone) that separate them from all other congeners. Based on morphology, biogeography, and recent inferences from plastid DNA sequence data, we place these distinctive species in a new genus, Benstonea Callm. & Buerki, making the necessary new combinations for the 50 recognized species, accompanied by six lectotypifications, one epitytification and two neotypifications, and placing seventeen names in synonymy. A generic key is provided to facilitate distinguishing Benstonea from the four other genera of Pandanaceae. Comments are provided on the distribution, ecology and typification of each accepted species.