Common name: Seagrass
Posidonia australis Hook.f. APNI*
Description: Submerged rhizomatous perennial seagrass; rhizomes to 10 cm long and 1–2 c. thick, enclosed in fibres from decaying leaf sheaths.
Leaves linear, flat, normally c. 50 cm long (occasionally longer) with a basal sheath and small ligule at the junction of sheath and blade, apex of lamina rounded-obtuse but normally eaten or worn truncate with marginal fibres slightly protruding.
Inflorescence usually not much exceeding the leaves, 5–12 cm long, each spike 3–8 cm long with usually, 3–6 bisexual flowers. Staminal connective persistent, attenuate; anther lobes red, 3.5–4.5 mm long.
Fruit 15–30 mm long, green or yellowish green with a thick fleshy outer pericarp; fruit floats until it disintegrates, releasing the seed; seed to c. 20 mm long.
Flowering: late spring to early summer.
Distribution and occurrence: Grows in clear saline water 1-10 m deep on sand or mud in estuarine or sheltered oceanic habitats; south from Broughton Is.
NSW subdivisions: NC, CC, SC
Other Australian states: Vic. Tas. W.A. S.A.
Text by S. W. L. Jacobs
Taxon concept: Flora of NSW 4 (1993)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.