Halodule uninervis  

Narrow leaved = (mean width range 0.90-1.21 mm, width range
                          0.5-1.5 mm)
Wide leaved    = (mean width range 2.16-3.21 mm, width range
                          1.5-4.0 mm)

Inhabit sublittoral areas as deep as 30 m but can invade into the intertidal area as far as the Avicennia forest (den Hartog 1970). [1]

In Malaysia, can be found in Kedah (Teluk Ewa, Pulau Langkawi), Perak (Teluk Nipah, Pulau Pangkor), Negeri Sembilan (Cape Rachado, Teluk Kemang, Pantai Port Dickson, Port Dickson), Melaka (Pulau Serimbun, Pulau Besar), Johor (Pulau Sibu, Pulau Sibu Tengah, Pulau Tinggi, Pulau Mentinggi, Pulau Besar), Terengganu (Sg. Redang estuary, Pulau Redang, Kuala Setiu), Sabah (Pulau Mabul, Pulau Sipadan, Pulau Gaya, Pulau Sepanggar, Pulau Manukan). [1]

This is an eurybiontic species. Its growth habit makes it a good substratum stabilizer and sediment accumulator. The leaf size varies with the substratum, being broader (up to 3.5 mm wide) in sheltered muddy areas and narrower (1mm wide) in exposed sandy shores. In Port Dickson, the average standing biomass was as 1.09g dry wt. m-2 in 1994. [1]

1. Phang, S.M. (2000). Seagrasses of Malaysia. Botanical   Monographs No. 2. Kuala Lumpur: University of Malaya