Desmococcus (alga)

Desmococcus
Scientific classification
Clade:	Viridiplantae
Division:	Chlorophyta
Class:	Trebouxiophyceae
Order:	Prasiolales
Family:	Stichococcaceae
Genus:	Desmococcus F. Brand, 1925
Type species
Desmococcus olivaceus (Persoon ex Acharius) J.R.Laundon[1]
Species[1]
Desmococcus apatococcus Desmococcus olivaceus Desmococcus spinocystis

Desmococcus is a genus of green algae in the family Stichococcaceae.[1] It is a subaerial genus of algae with a cosmopolitan distribution.[2]

Algae in the genus Desmococcus were first named in 1777 by J.C.D. von Schreber, who thought it was a lichen and named it Lichen viridis. After being redescribed in various other genera such as Pleurococcus or Protococcus, the genus was described in 1925 by F. Brand with D. vulgaris as its type. The type species is Desmococcus olivaceus.[3]

Molecular data show that Desmococcus is closely related to Stichococcus and related genus, a common genus of algae with rod-shaped cells. Desmococcus differs from Stichococcus and its congeners in morphology (having sarcinoid colonies or short branched filaments, and the ability to produce zoospores).[4]

Description

Desmococcus consists of cells found in cuboidal packets (sarcinoid habit) or short branched uniseriate filaments. Cells are uninucleate[1] with a single, trough-shaped chloroplast and a pyrenoid; however, the pyrenoid is naked and difficult to see.[5] Asexual reproduction occurs by the production of aplanospores 4-flagellate zoospores which are produced in large, spherical sporangia; the sporangia have a punctate, verrucose, or smooth outer cell wall.[6] Sexual reproduction has not been observed in this genus.[1]

Habitat

Desmococcus is very common and has been described as "the most common subaerial alga world-wide". It typically grows on damp, soil-free surfaces such as tree trunks, wooden poles, and other surfaces where lichens are uncommon.[2]

References

1. Guiry, M.D.; Guiry, G.M. "Desmococcus F.Brand, 1925". AlgaeBase. University of Galway. Retrieved 2025-01-03.
2. D. M. John; Brian A. Whitton; Alan J. Brook, eds. (2002). The freshwater algal flora of the British Isles: an identification guide to freshwater and terrestrial algae. Cambridge University Press. ISBN 978-0-521-77051-4.
3. Laundon, Jack R. (1985). "Desmococcus olivaceus — The Name of the Common Subaerial Green Alga". Taxon. 34 (4): 671–672. doi:10.2307/1222212. JSTOR 1222212.
4. Pröschold, Thomas; Darienko, Tatyana (2020). "The green puzzle Stichococcus (Trebouxiophyceae, Chlorophyta): New generic and species concept among this widely distributed genus". Phytotaxa. 441 (2): 113–142. doi:10.11646/phytotaxa.441.2.2.
5. Shubert, Elliot; Gärtner, Georg (2014). "Chapter 7. Nonmotile Coccoid and Colonial Green Algae". In Wehr, John D.; Sheath, Robert G.; Kociolek, J. Patrick (eds.). Freshwater Algae of North America: Ecology and Classification (2 ed.). Elsevier Inc. ISBN 978-0-12-385876-4.
6. Ettl, Hanuš; Gärtner, Georg (2013). Syllabus der Boden-, Luft- und Flechtenalgen (in German) (2nd ed.). Springer-Verlag. ISBN 9783642394614.