Pandanus grayorum Callm., Buerki & Gallaher (Pandanaceae) is newly described from the Wet Tropics of north-eastern Queensland in Australia. It is the second Australian species other than P. gemmifer H.St.John known to reproduce by axillary plantlets on aerial branches. It can be distinguished from P. gemmifer and P. solms-laubachii F.Muell. by the dimensions of its leaves, shape and dimensions of its syncarps, and by the morphology of its phalanges. The placement of P. grayorum in a molecular phylogeny confirmed morphological evidence and showed that the new species clusters with P. gemmifer and P. solms-laubachii in a clade closely related to the P. tectorius Parkinson complex. Pandanus grayorum is known from near the banks of the lower reaches of Mulgrave, Russell, Johnstone and Moresby rivers and associated subcoastal flood plains. Most collection records are from areas outside national parks and a preliminary conservation assessment of Vulnerable is suggested using the IUCN Red List. Finally, a key to north-eastern Queensland Pandanus species is also provided.

Pandanus odorifer(Pandanaceae) is an economically important species distributed on coasts from India and Sri Lanka to South China through tropical Asian countries.Pandanus odoratissimushas been widely used as the accepted name for the species, butP. odoratissimusis in reality a superfluous and illegitimate name. No original material ofP. odoriferhas been traced, and a neotype is designated here for that name.

Pandanaceae (screwpines) is a monocot family composed of c. 750 species widely distributed in the Paleotropics. It has been proposed that the family may have a Gondwanan origin with an extant Paleotropical distribution resulting from the breakup of that supercontinent. However, fossils supporting that hypothesis have been recently reassigned to other families while new fossil discoveries suggest an alternate hypothesis. In the present study, nuclear and chloroplast sequences were used to resolve relationships among Pandanaceae genera. Two well-supported fossils were used to produce a chronogram to infer whether the age of major intra-familial lineages corresponds with the breakup of Gondwana. The Pandanaceae has a Late Cretaceous origin, and genera on former Gondwanan landmasses began to diverge in the Late Eocene, well after many of the southern hemisphere continents became isolated. The results suggest an extant distribution influenced by long-distance-dispersal. The most widespread group within the family, the Pandanus tectorius species complex, originated in Eastern Queensland within the past six million years and has spread to encompass nearly the entire geographic extent of the family from Africa through Polynesia. The spread of that group is likely due to dispersal via hydrochory as well as a combination of traits such as agamospermy, anemophily, and multi-seeded propagules which can facilitate the establishment of new populations in remote locations.