Dictiota dichotoma (Lamour, 1809)

Dictiota dichotoma imageSynonyms: 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.

Dictiota dichotoma arealIUCN Status:
    World level:
    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.


  1. Kalugina-Gutnik A.A. Phytobenthos of the Black Sea .- Kiev.: Naukova Dumka, 1975. - 245 p.
  2. Red Book of the Ukraine. Plant`s wold. -Kiev.: Ukr. intsykloped., 1996. - P.494.
  3. Zinova A.D. Definition of green,brown and red algae of the southern seas of the USSR. - Leningrad.: Nauka, 1967. - 397 p.

Compiled by: G.Minicheva.