Pandanus is a genus of monocots with about 578 accepted species. They are palm-like, dioecious trees and shrubs native to the Old World tropics and subtropics. Common names include pandan, screw palm and screw pine. The genus is classified in the order Pandanales, family Pandanaceae, and is the largest in the family.
Description
Aerial, prop roots
The species vary in size from small shrubs less than
They are dioecious, with male and female flowers produced on different plants. The flowers of the male tree are 2–3 cm (3⁄4–1+1⁄4 in) long and fragrant, surrounded by narrow, white bracts. The female tree produces flowers with round fruits that are also bract-surrounded.
The individual fruit is a drupe, and these merge to varying degrees forming multiple fruit, a globule structure, 10–20 cm (4–8 in) in diameter and have many prism-like sections, resembling the fruit of the pineapple. Typically, the fruit changes from green to bright orange or red as it matures. The fruits can stay on the tree for more than 12 months.
Evolution
The oldest credible fossil of the genus is Pandanus estellae, which is known from a silicified fruit found in Queensland, Australia, dating to the Oligocene epoch around 32–28 million years ago. Phylogenetic analyses of the maternal DNA of Pandanus has shown the genus to be divided into two large groups (Clade I and Clade II), with each of those groups further subdivided into two smaller groups (Subclade Ia, Subclade Ib, Subclade IIa, and Subclade IIb). The split between Clades I and II was determined to have occurred during the early Miocene, whereas the splits between Subclade Ia and Ib and between Subclade IIa and IIb were determined to have occurred during the Middle Miocene Climatic Optimum.
Nuclear target-capture genomics revealed that the evolutionary trajectory of the genus was heavily shaped by reticulate evolution and transoceanic adaptive introgression across the Indian Ocean. Nuclear...
