[1] Species in the genus are macroscopic, siphonous marine green algae that are made up of units of single tubular filaments.

[1][4] It tends to have a morphology that is simple, non-calcified and siphonous multinucleate filaments with no cross walls, with axes that are erect and uniaxial.

[11][12] Organisms are single tubular cells that are siphonous, which is a term used to describe algae in which the thallus is not compartmentalized and typically contains a large vacuole surrounded by an outer later of protoplasm.

[13][14] The thallus is commonly erect and occurs in two morphologies corresponding to haploid or diploid life cycle stages: the macrothallus and microthallus.

[1] The fronds of Bryopsis vary among species from deltoid to lanceolate and the pinnules are most commonly in radial, distichous or secund arrangements.

[5] The apical development and arrangement of transverse microfibrils play an important role in the lateral and longitudinal growth of the cell wall structure.

The literature suggests that the fast rate of repair to photosystem II and transient photoinactivation are mechanisms that this genus uses to help mitigate photodamage from excess sun light.

[3] The siphonous morphology of Bryopsis also plays an important role in adapting to changing light conditions on the intertidal shores; affecting light-harvesting modulation in some species of this genus.

[3] Some species of Bryopsis have a protective state in which their bodies discriminate between surface filaments that get high exposure to the sun from those that reside in underlayers.

[19] Bryopsis contains mostly epilithic but sometimes free-floating algae that occupy a range of habitats including seaweed beds, shallow fringing reefs and both sheltered and well-exposed subtidal areas.

For example, in Singapore it represents one of the four functional-form groups that makes up approximately 20-40% of benthic cover across coral reefs[4] and along the east coast of the United States and the Caribbean, where clusters of species from this genus dominate intertidal regions.

These effects extend beyond the duration of chemical exposure because even when no traces remained, the mortality rate of coral larvae continued to increase in experimental conditions.

[22] Additionally, the coral skeleton that remains after tissue degradation optimizes colonization by microalgae, which attach to the exposed hard substrate.

Rising sea water temperatures and eutrophication are thought to be major factors responsible for the development of green tides.

Bryopsis micro-propagules in the form of gametes, spores and zygotes attach to existing mature thalli or seaweed beds and this initiates the green tides.

They are often found on the surface and in the cytoplasm or vacuoles of the cells and can influence the life cycle as well as different metabolic functions such as growth factors, and the fixation of nitrogen and antimicrobial compounds of the macroalgae.

The latter supports the theory of vertical transmission of endophytic bacteria, implying a stable and mutualistic relationship between the host and its endobionts.

[24] A strong host specific association between Flavobacteriaceae endosymbionts and Bryopsis has been cited in literature to aid nitrogen fixation in the algae.

[24] Generalist phylotypes fulfill metabolic functions such as nitrogen-fixation (Rhizobiaceae), anoxygenic photosynthesis (Phyllobacteriaceae) and CO-oxidation (Labrenzia).

[25][21] Clinical trials have demonstrated that when KF is combined with its other isomers it is highly sensitive to drug resistant strains of cancer.

Potentially invasive green algae that grow as a result of algal blooms could be recovered to extract KF for clinical purposes.

[26] This is thought to be a pragmatic approach to addressing the ecological impact of green macroalgae blooms and the economic burden associated with manufacturing KF for clinical trials.

Bioactive compounds are also known to be present among Bryopsis, specifically among B. pennata and B. plumosa with different biological activities such as antifungal, antibacterial, and anticoagulant properties.

Eradication can be achieved through the use of grazers (including several crabs, mollusks, and sea urchins), manual removal, light starvation, and nutrient reduction.

[15] In 1823, Bory de Saint Vincent brought forth the family of green algae Bryopsidaceae which included the genus Bryopsis, (Bryopsidales, Ulvophyceae and Chlorophyta).

The differentiation of new genera, such as Bryopsidella, which was previously reported as Bryposis halymeniae and Derbesia neglecta, resulted from the identification of its unique life history.

[12] Continuous morphological variations and their inherently simple thallus structure has made it difficult to differentiate species within this genus.

Bryopsis was originally described by Lamouroux in 1809, providing information on five species based on morphological appearance, specifically the pinnules, its number, lengths, and arrangement.

In order to fully understand the diversity within the genus, different physiological aspects have been analyzed (e.g. life cycle, chromosomes) however, these have been insufficient in further elucidating taxonomic issues within species.