Cystophora

Cystophora is a genus of brown algae (phaeophyceae) in the order Fucales, comprising multiple species that occur in temperate coastal waters of the Southern Hemisphere. The genus is especially associated with the coasts of Australia and New Zealand, with some species found along nearby temperate regions. Cystophora forms part of rocky-subtidal and shallow-water algal communities and can contribute to local biodiversity by providing structure and habitat for other marine organisms.

Morphology and anatomy of Cystophora species generally feature erect, branching thalli that can reach several tens of centimeters in length. The thallus is typically brown to olive-brown and may possess numerous vesicles or air bladders along the branches, which can influence buoyancy and form a bushy or feathery appearance. Surface texture ranges from smooth to slightly rough, and reproductive conceptacles are embedded in the thallus where gametes are produced.

Reproduction in Cystophora follows the brown algae pattern of alternation of generations, with a macroscopic diploid sporophyte producing haploid spores that develop into microscopic gametophytes. Gametes fuse to form a zygote, which grows into a new sporophyte, completing the cycle. This life history is typical of many Fucales and contributes to genetic diversity within populations.

Ecology and habitat preferences center on shallow subtidal to low intertidal rocky reefs and sheltered coastal areas. Cystophora blades provide habitat and shelter for small invertebrates and juvenile fish and offer surfaces for epiphytic algae and microorganisms. They are sensitive to environmental changes such as rising sea temperatures, pollution, and habitat disturbance, making them useful indicators in marine biodiversity assessments.