Home / Charophyceae / Filaments / Desmids / Desmidium
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Name derivation:
"Bundle formation" -- Bundle (desmid-) formation (-ium)
Classification:
Desmidium C.Agardh ex Ralfs 1848; 20 of 135 species descriptions are currently accepted taxonomically (Guiry and Guiry 2014). Order Desmidiales; Family Desmidiaceae
Morphology:
Cells appear in a long, single row of filaments. Cells connect to adjoining cells at the flat, apical face of the cells. The cells can be longer or shorter than wide. A median constriction of the cells may appear either as distinct or faint. Desmidium cell walls are smooth with multiple side-by-side or scattered pores. Every semicell contains one stellate chloroplast. Typically cells are oval in shape or have a three to five angle. Angles of the cell are often offbalance on each semicell. This creates a helical shape of angles throughout the filament. Cells may have either a pyrenoid (transparent structure) in each of its lobes or a single pyrenoid in the middle of the cell. The nucleus is found in the conjoined area of semicells (isthmus).
Similar genera:
Bambusina is related to Desmidium in cell division which creates an additional secondary wall. The two genera are also similar in the morphogenesis of semicells. Both Bambusina and Desmidium contain semicells with one chloroplast.
Habitat:
There are twenty known species. Sixteen species can be found in North America. Acidic, Oligotrophic bogs, ponds, or lakes are the main habitat. A seasonal study on the Shivnath River, India (N 21^°) found the Desmidium to be most abundant during the winter (Pandey and Pandey 2014).
References:
Gerrath JH. 2003. Conjugating Green Algae and Desmids. In: Wehr JD, Robert SG, editors. Freshwater Algae of North America: Ecology and Classification. San Diego (CA): Academic Press. p 374-5. Guiry, M.D. and G.M. Guiry 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 30 May 2014. Pandey, B. and P. Pandey 2014. Phytoplankton diversity and seasonal variations in the Shivnath River, Durg-Bhilai. Advances in Biology and Biomedicine. 1-4.