The screw pine is neither a pine nor, despite appearances, a palm
Pandanus trees go by names like screw pine and pandanus palm, yet they are not closely related to either. They are monocots propped on thick stilt roots, crowned with strap-like leaves, and bearing heavy fruit that looks like a pineapple and can hang on the tree for over a year.
The genus holds about 578 accepted species, making it the largest in its family, and ranges across the tropics and subtropics of the Old World. Plants run from shrubs under a metre to trees 20 metres tall with broad canopies. Trunks are stout, marked with rings of old leaf scars, and supported by branching roots that sprout from the stem and brace the plant as it grows top-heavy. Leaves, sometimes spiny, can be anywhere from 30 centimetres to 2 metres long.
Each plant is either male or female. Males bear fragrant flowers a few centimetres long wrapped in narrow white bracts. On female trees, many small drupes fuse into a round compound fruit 10 to 20 centimetres across, divided into prism-shaped sections, that ripens from green to bright orange or red.
The name travelled far. It comes from the Malay pandan, used for Pandanus amaryllifolius, the best-known species, and traces back to a Proto-Austronesian root. Relatives of that word turn up across the Austronesian world, from Tagalog pandan to Malagasy fandrana, Tahitian fara and Hawaiian hala, a sign of how much these plants have mattered to Austronesian-speaking peoples. Māori even applied related words to quite different plants with similar uses.
Pandanus has deep roots in time as well. The oldest credible fossil, a silicified fruit named Pandanus estellae from Queensland in Australia, is roughly 32 to 28 million years old. DNA studies show the genus's history was tangled by hybridisation and gene flow across the Indian Ocean, with one lineage that includes the widespread Pandanus tectorius acting as a bridge between Asian and Afro-Malagasy populations. Meanwhile, swamp-dwelling lineages in separate regions look alike not because they are related but because similar climates shaped them the same way. Those findings have also undermined the traditional six-subgenus classification.
Source: Pandanus
