Dictyosphaeria cavernosa

Chlorophyta, Siphonocladaceae

Authority: (Forsskål) Børgesen

Hawaiian name: none

Characteristic feature: Large round green cells forming hollow spheres when small, which rupture to form convoluted cup shapes with growth. Green bubble algae.

Description: Plants to 12 cm diameter, a hollow bladder with single-layer wall of cells at first, becoming convoluted or ruptured with secondary monostromatic bladders attached to parent bladder; polygonal segments to 5 mm diameter. Isodiametric hapteroid cells, 35-45 µm in diameter, attaching segments to one another.

Habitat: Rock and sand substrates, low intertidal pools; cement walls; subtidal to 60 m; loose on the bottom in very still areas.

Hawaiian distribution: All main Hawaiian Islands, including the Northwestern Hawaiian Islands.

Other: Highly successful native invasive species, particularly in reef communities experiencing nutrient enrichment and overfishing.

Dictyosphaeria versluysii, also common in Hawaiian waters, forms smaller (to 5 cm diameter), always rounded, solid cushions.