New Guinea has the world's richest island flora.
Cámara-Leret R., Frodin DG., Adema F., Anderson C., Appelhans MS., Argent G., Arias Guerrero S., Ashton P., Baker WJ., Barfod AS., Barrington D., Borosova R., Bramley GLC., Briggs M., Buerki S., Cahen D., Callmander MW., Cheek M., Chen C-W., Conn BJ., Coode MJE., Darbyshire I., Dawson S., Dransfield J., Drinkell C., Duyfjes B., Ebihara A., Ezedin Z., Fu L-F., Gideon O., Girmansyah D., Govaerts R., Fortune-Hopkins H., Hassemer G., Hay A., Heatubun CD., Hind DJN., Hoch P., Homot P., Hovenkamp P., Hughes M., Jebb M., Jennings L., Jimbo T., Kessler M., Kiew R., Knapp S., Lamei P., Lehnert M., Lewis GP., Linder HP., Lindsay S., Low YW., Lucas E., Mancera JP., Monro AK., Moore A., Middleton DJ., Nagamasu H., Newman MF., Nic Lughadha E., Melo PHA., Ohlsen DJ., Pannell CM., Parris B., Pearce L., Penneys DS., Perrie LR., Petoe P., Poulsen AD., Prance GT., Quakenbush JP., Raes N., Rodda M., Rogers ZS., Schuiteman A., Schwartsburd P., Scotland RW., Simmons MP., Simpson DA., Stevens P., Sundue M., Testo W., Trias-Blasi A., Turner I., Utteridge T., Walsingham L., Webber BL., Wei R., Weiblen GD., Weigend M., Weston P., de Wilde W., Wilkie P., Wilmot-Dear CM., Wilson HP., Wood JRI., Zhang L-B., van Welzen PC.
New Guinea is the world's largest tropical island and has fascinated naturalists for centuries1,2. Home to some of the best-preserved ecosystems on the planet3 and to intact ecological gradients-from mangroves to tropical alpine grasslands-that are unmatched in the Asia-Pacific region4,5, it is a globally recognized centre of biological and cultural diversity6,7. So far, however, there has been no attempt to critically catalogue the entire vascular plant diversity of New Guinea. Here we present the first, to our knowledge, expert-verified checklist of the vascular plants of mainland New Guinea and surrounding islands. Our publicly available checklist includes 13,634 species (68% endemic), 1,742 genera and 264 families-suggesting that New Guinea is the most floristically diverse island in the world. Expert knowledge is essential for building checklists in the digital era: reliance on online taxonomic resources alone would have inflated species counts by 22%. Species discovery shows no sign of levelling off, and we discuss steps to accelerate botanical research in the 'Last Unknown'8.