Halodule pinifolia

Halodule pinifolia is a common seagrass in Asian tropical coasts. It forms homogenous patches in intertidal zones, or it is occasionally intermixed with other seagrasses such as Halodule uninervis.^[3] Halodule pinifolia grows in sandy or muddy sand substrates from upper littoral to subtidal areas. It is ephemeral with rapid turn-over and high seed set and is well adapted to high levels of disturbance. This species is can grow rapidly and is a fast coloniser, often heavily epiphytised.^{[citation needed]}

Halodule pinifolia has been studied at Laucala Bay on the island of Viti Levu, Fiji.^[4]

Compared with the closely related Halodule uninervis, Halodule pinifolia has a narrower blade size (1 mm versus 4 mm).^[3] Its fine, delicate leaves are up to 20 cm long, with one black central vein that splits into two at the rounded leaf tip. It usually has a pale rhizome, with clean black leaf scars.^{[citation needed]}

In Fiji, Halodule pinifolia was observed to undergo hydrophilous pollination, in which pollen disperses directly on the water surface. Prior to dehiscence^[4] during low spring tides, the long filaments bearing the anthers become erect^[5] above the mass of filiform leaves. Once exposed to air, the 32 mm long filaments burst, releasing a cotton-like mass of filiform pollen which assemble into floating rafts on the water surface.^[5][4] Halodule pinifolia was found to be strictly dioecious.^[4]

This species is known to be hybridized to Halodule uninervis in Okinawa, Japan.^[2]