Dictiota dichotoma (Lamour, 1809)
Synonyms: Ulva dichotoma Hudson, 1762.
Common names: Russ: Diktiota dikhotomicheskaya.
Order (Scientific): DICTYOTALES.
Family (Scientific): DICTYOTACEAE.
Taxonomic descriptions: The tallus are 10-20 cm with numerous attached risodes. The tallome is rude leathern, dichotomical divided into numerous segments 2-8 mm width. The tops of the segments are oval shape or forked. The diameter of the tetrasporangs are 100-150 mcm, usually single, distribited on the surface of the tallome.
Black Sea Regional level:
Subregion level: EN (Ukraine)
Habitats type, Critical habitats, Limiting factors: On rocks, stones and shells. Disturbed rocky-stony biotops. High concentration of organic matter.
Biology: One-years. Reproduction carried out in two ways: sexual and not-sexual.
Population trends: In the 1960s it dominated in Dilopheta associations. The average biomass was 380 g/m2 . At present D. dichotoma is a rare species.
Threats: Hydrotechnical construction, eutrophication.
Conservation measures taken: Included in the Red Book of the Ukraine.
Conservation measures proposed: Protection of the biotops. Lowering the level of eutrophication.
Compiled by: G.Minicheva.