Page 54 - Invasive_Species_2013

Mediterranean invasive species factsheet

ANGIOSPERM

Reproduction Common name: Halophila seagrass

Mid-rib
identification Fronds in pairs

Scientific Name:
Halophila stipulacea
Picture

Key identifying features

This euryhaline marine seagrass consists of thin, Brief history
creeping rhizomes (0.5–2 mm in thickness) from
which pairs of thin leaves emerge at regular intervals.
The leaves have a serrated edge and are 3–6 cm
long and 2.5–8 mm wide. The rhizomes are fixed to
the sand by roots emerging from each node.

Field identification signs and habitat

In its original range, Halophila stipulacea grows in a
wide range of environmental conditions and coastal
substrates. However, this species has a much
narrower ecological distribution in the eastern
Mediterranean, being limited to soft substrates (sand
and mud) only.

It can be found forming monospecific or mixed
meadows with the native sea grass, Cymodocea
nodosa.

Halophila stipulacea. Photo: P. Francour

Reproduction
Male and female plants are separate, producing
solitary male or female flowers at each leaf node. It
is a fast-growing species and produces many seeds,
colonizing and spreading rapidly from small
populations. In the Mediterranean the main flowering
season occurs in July–August, with fruits ripening in
September.
Halophila stipulacea. Photo: J. Garrabou

Monitoring Marine Invasive Species in Mediterranean MPAs: A strategy and practical guide for managers 51