Monographic studies in Pandanaceae continue to yield previously unrecognized taxa both at specific and higher ranks. In Pandanus, with the increase of knowledge of staminate structures becoming available through better collections and more critical observations, use of staminate characters integrated with previously known data is providing important new insights into infrageneric taxa and their affinities, as well as completing the fundamental descriptions at species rank important for both systematic and ecological studies. In the results reported here two new species, Pandanus calvus and P. kosteri, and two new sections, Hastatistigma (based on P. vinaceus) and Macrokurzia (based on P. daymanensis) are proposed. Two species previously known only from pistillate materials, P. cernuifolius and P. irregularis, are clarified by description of staminate specimens, while in the case of P. copelandii, a previously unrecognized staminate feature is described. Field data for the inadequately known species P. leptocarpus are provided, and the first illustrations of the type specimen (staminate) of P. houlletii are provided. These taxa are discussed under the subgenera to which they are referred in the synopsis (Stone, 1974).