Amphibolis spp.

sea nymph

Temperate coastal waters of southern and western Australia

Overview

Amphibolis spp. is a genus of two marine seagrass species in the family Cymodoceaceae, distributed along the temperate coasts of southern and western Australia. Plants grow fully submerged in subtidal sandy and rocky seabeds, anchored by branching rhizomes and wiry, woody stems that reach 8-60 in (20-150 cm) in height. The stems carry clusters of strap-shaped leaves 0.4-1.6 in (1-4 cm) long at their tips, each leaf 0.08-0.2 in (2-5 mm) wide. Leaf bases persist as fibrous remnants along older stems. The genus is dioecious, with separate male and female plants, and reproduces by seedlings that develop on the parent plant before release. A. antarctica and A. griffithii form underwater meadows that stabilise sediments and shelter marine invertebrates and fish. Growth is slow, and damaged meadows recover over years to decades. As fully marine plants, Amphibolis spp. cannot be grown in terrestrial gardens or freshwater systems, and propagation outside its native marine habitat is not practiced. Foliage remains green year-round.

Native Range

Amphibolis spp. occurs in the temperate coastal waters of southern and western Australia, from Western Australia across South Australia to Victoria and Tasmania. Both species are endemic to this region.

Suggested Uses

Amphibolis spp. meadows function ecologically as sediment stabilisers and nursery habitat for fish and invertebrates in temperate Australian coastal waters. The genus is encountered in marine ecology study and seagrass restoration rather than in horticulture.

How to Identify

Identify Amphibolis spp. by its wiry, branching woody stems rising from rhizomes buried in marine sediment, topped with clusters of short strap-shaped leaves 0.4-1.6 in (1-4 cm) long. Persistent fibrous leaf-base remnants sheath the older stem sections. Female plants bear seedlings with grappling structures that separate the genus from co-occurring seagrasses such as Posidonia spp..

Appearance

Size & Dimensions

Height8" - 5'

Colors

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Flowering occurs underwater and is inconspicuous, with separate male and female plants releasing and receiving pollen through the water in late winter to spring (roughly July-October in the Southern Hemisphere). Fertilised female plants retain developing seedlings for several months before releasing them. No showy floral display is produced.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Water & Climate

Water Needs

High

Care & Maintenance

Care Guide

Amphibolis spp. grows only in fully marine subtidal habitats and is not cultivated in gardens or aquaria under normal conditions. In its native setting it requires clear, well-oxygenated seawater of normal oceanic salinity, sandy or rocky substrates for rhizome anchorage, and light penetration to depths of around 6-100 ft (2-30 m). Water temperatures range from roughly 50-72 F (10-22 C) across its range. Sediment disturbance, declining water clarity, and physical damage from boat moorings reduce meadow cover, and recovery is slow because the genus spreads mainly by rhizome extension. Restoration relies on transplanting whole shoots or seedlings into suitable seabed.

Pruning

Pruning does not apply to this marine genus. In the wild, older stems shed leaf clusters and fibrous sheaths while rhizomes extend to form new shoots, renewing the meadow over successive seasons.

✓ Toxicity

Non-toxic

Amphibolis spp.

sea nymph

Cymodoceaceae

Temperate coastal waters of southern and western Australia

WaterHigh

Overview

Native Range

Suggested Uses

How to Identify

Appearance

Size & Dimensions

Height8" - 5'

Colors

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Detailed Descriptions

Foliage Description

green

Growing Conditions

Water & Climate

Water Needs

High

Care & Maintenance

Care Guide

Pruning

Pruning does not apply to this marine genus. In the wild, older stems shed leaf clusters and fibrous sheaths while rhizomes extend to form new shoots, renewing the meadow over successive seasons.

✓ Toxicity

Non-toxic