The Pandanaceae family has 5 genera with over 1000 species the most important genus being Pandanus.
Australia has over 30 native species of Pandanus including P. spiralis and P. tectorius that are found in Queensland.
Common names include Screw pine, Pandan and Pandanus palm although they are not a pine or palm.
Because the appearance of the various species is similar the following is a general description.
It excludes Sararanga which has some differences.
Plants are woody trees from 5 to 20 m high with an erect trunk with many forked branches.
The common P. spiralis can grow as a shrub or small tree.
Aerial (adventitious, prop or stilt) roots, up to 1 m long, grow from the lower part of the trunk.
The trunk, props and branches, with grey or brown bark, may have short, spiny nodules or warts.
The leaves are tightly clustered at the ends of branches.
They are arranged in 3 ranks (4 in the Sararanga genus).
Due to the branch twisting as it grows the leaves appear to be spirally arranged.
This appearance gave rise to the name Screw pine.
The upper &/or lower leaf surfaces can have a white bloom.
The long, narrow leaves are up to 2 (3) m long and 10 cm wide with parallel veins.
The ends of the leaves droop down.
The midrib is prominent below with a corresponding groove on the upper surface.
Leaf bases sheath the stem and leave prominent scars when they fall.
Many species have small teeth on all or part of the leaf margin and sometimes the midrib.
Dead leaves may remain on the tree for a considerable time.
Inflorescences are mostly terminal and their form varies.
The flowers are tiny and on stalks with bracts at the base.
There may be no perianth or a 3 to 4 lobed cup.
Plants are either male or female.
Male flowers are in groups surrounded by white or coloured bracts.
They have many stamens with fleshy filaments and there may be infertile staminodes.
There is a rudimentary ovary – a pistillode.
Female flowers have an ovary, with or without a conical style, and a stigma.
They are in tightly packed groups that form the green segments or phalanges.
Fruit are up to 30 cm long and resemble a large pineapple with from 8 to over 200 segments.
The green segments ripen to orange, red or yellow.