Common screwpine

Pandanus utilis

The common screwpine is, despite its name, a monocot and not a pine.
It is native to Madagascar, Mauritius, and the Seychelles.
On the lava flow at the edge of the sea The Piton de Takamaka overflowed to the sea many years ago. a lone tree stands at the edge of the coast.  Geotagged,Indian Ocean,Pandanus utilis,Reunion,Reunion 2016,Winter,winbter

Appearance

The trunk features aerial prop roots. The leaves are linear and spiny, with a spiral arrangement on the tree. The leaves are also dried out and rolled, and used to make mats in Kerala, India; and Hawaii.
Care must be taken when handling the leaves because of their sharp spines.

The fruit of ''Pandanus utilis'' is edible, although not flavorful to humans and must be cooked prior to consumption.
It attracts mammals such as, in North America, squirrels.''Pandanus utilis'' is a palm-like evergreen tree, ranging in height up to 20 metres . They are found in tropical areas and have an upright trunk that is smooth with many horizontal spreading branches with annular leaf scars. Old leaf scars spiral around the branches and trunk, like a screw. The anatomy of Pandanaceae stems can be distinguished from other monocotyledons by the presence of a compound vascular bundle. This bi- or tripolar vascular bundle has two or three distinct conduction strands encased by a common bundle sheath. At the end of each branch is a spiral cluster of long, linear leaves with a pectinate edge tapering to a long point at the apex. This margin is filled with small reddish colored teeth. The leaves are simple without lobes and can be up to 2 metres long and 3 to 11 centimetres broad. They are without petioles and are broadly clasped at the base. The leaf venation is parallel running longitudinal. The blue/green to dark green leaves is rather stiff with a waxy texture. The leaves of ''P. utilis'' have a spongy tissue with numerous fibers arranged in bundles. These bundles can contain over 150 fibers.

As with other member of the genus Pandanus, ''P. utilis'' lacks secondary growth. The secondary growth of most trees is the production of wood to aid in support of the trunk. Without this supportive structure, the ''P. utilis'' grows many pale brown prop roots at the base of the trunk. These adventitious roots arise from the stem above the soil level and help support the plant. These roots not only anchor the tree but also keep it upright during times of heavy winds and rain in tropical regions. Prop roots can be 2.5 to 7.5 centimetres in diameter.

''P. utilis'' is dioecious, with the female and male reproducing structures occurring on different plants. Individual plants are either male producing microspores or female producing megaspores. This plant being unisexual allows it to cross-fertilize with other screwpines. The male plants produce fragrant colorful flowers in long spikes. These long spikes are with 8–12 stamens inserted pseudo-umbellately on slender columns 10 to 15 millimetres long. The female plants produce fruits resembling pineapples or oversized pine cones changing from green to yellow/orange when ripe. The female structure has a 3–8 celled ovary crowned by a sessile stigma.

Habitat

''P. utilis'' grows well near the sea, being salt-tolerant. It is a strictly tropical tree that will not survive frost. It grows in full sun to partial shade but prefers at least 6 hours of direct sunlight. Seeds take two to three months to germinate.

References:

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Taxonomy
KingdomPlantae
DivisionAngiosperms
ClassMonocots
OrderPandanales
FamilyPandanaceae
GenusPandanus
SpeciesP. utilis
Photographed in
RĂ©union