Penium

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Penium
Penium polymorphum (68 × 25 µm)

Penium polymorphum (68 × 25 µm)

Systematics
without rank: Chloroplastida
without rank: Charophyta
Class : Ornamental algae (Zygnemophyceae)
Order : Ornamental algae (Desmidiales)
Family : Peniaceae
Genre : Penium
Scientific name
Penium
Brébisson ex Ralfs

Penium is a globally occurring genus of algae from the group of ornamental algae (Desmidiales), whichcomprisesaround 25 recognized taxa .

description

Penium are unicellular algae, cylindrical and straight in shape, broadly rounded or blunt at the ends, occasionally they are slightly constricted in the middle. They measure 19 to 450 microns in length and one-half to one thirty-fifth in width. Belt straps may be present or absent.

The cell wall, which is occasionally brown and then often colored differently in the different areas of the wall, can be smooth or sculptured by stripes, pores, granulations or spikes. The cell wall has two layers, the outer layer is perforated, the inner one impermeable. Each cell has two, rarely four, chloroplasts . In some species there are small crystals in the end vacuoles. The cell nucleus lies in the middle between the chloroplasts.

Penium species multiply asexually by cell division , sexually by conjugation . The round to elliptical, occasionally angled zygospores occur singly or in pairs, their surface is usually unsculptured.

distribution

The genus is distributed worldwide, mostly in acidic, nutrient-poor ponds or lakes, also in peat moss .

Systematics and research history

The genus, first described in 1848, contains around 25 recognized taxa, including

proof

  1. ↑ a b c d e M.D. Guiry, GM Guiry: Penium Brébisson ex Ralfs in Ralfs, 1848: 148 :: Algaebase , 2010 World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org , accessed August 12, 2010

further reading

  • John Ralfs: The British Desmidieae. 14. Penium. Pp. 149–154, London 1848 First description in full text (English)
  • J. Lütkemüller: On the knowledge of the genus Penium Bréb. Negotiations of the Zoological-Botanical Society, 55, pp. 332–337, 1905 full text (PDF, German; 521 kB)

Web links

Commons : Penium  - collection of pictures, videos and audio files