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Characeae

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Characeae

Stoneworts
Chara globularis
Scientific classification
Kingdom: Plantae
Division: Charophyta
Class: Charophyceae
Order: Charales
Family: Characeae
Genera

Chara
Lamprothamnium
Lycnothamnus
Nitella
Nitellopsis
Tolypella

Charales is an order of pondweeds, algae in the division Charophyta. They are green plants believed to be the closest relatives of the green land plants. Linnaeus established the genus Chara in 1753. Most are found in fresh water, but some charophytes have been found in ephemeral saline lakes in Australia, healthy and photosynthesizing at twice the salinity of seawater.[1]

Description

The Charales have large, macroscopic thalli growing up to 120 cm long, they are branched, multicellular, and use chlorophyll to photosynthesize. They grow in fresh water. They may be called stoneworts,[2] because the plants can become encrusted in lime (calcium carbonate) after some time. The "stem" is actually a central stalk consisting of giant, multinucleated cells. They are unique in having a whorl of small branchlets at each node in the stipe, this gives them a superficial resemblance to the genus Equisetum. In these whorls it is possible to see the phenomenon of cytoplasmic streaming. In fact the streaming in Chara is the fastest recorded of any cell. Cytoplasmic streaming is caused by the microfilaments found inside the cell, as proven by the use of cytochalasin B to stop streaming.

There are about 400 species worldwide, with 33 in Britain and Ireland according to Groves and Bullock-Webster),[3][4] however Stewart and Church (1992) reduce this to 21.[5]

Characeae are the principal plant life of some of the volcanic crater lakes of Nicaragua, and can be found in excess of 20 meters depth in some circumstances. Introduced tilapia (Oreochromis niloticus) consumed all the Characeae in Lake Apoyo.[6]

Species


British Isles

Ref: Stewart & Church (1992).[5]

  • Chara baltica Bruz.
  • Chara canescens Desv. & Lois.
  • Chara connivens Salzm. ex A.Braun
  • Chara curta Nolta wx Kütz. (=C.aspera var. curta)
  • Chara denudata (A.Braun) R.D.Wood
  • Chara fragifera Durieu
  • Chara intermedia Braun (=C. papillosa Kütz. and C. contraria x hispida)
  • Chara mucosa J.Groves & Bullock-Webster
  • Chara rudis (A.Braun) Leonh.
  • Chara tomentosa L.
  • Lamprothamnium papulosum (Wallr.) J.Groves
  • Nitella capillaris (Krocker) J.Groves & Bullock-Webster
  • Nitella gracilis (Smith) Agardh
  • Nitella hyalina (DC.)Agardh
  • Nitella mucronata (A.Braun)Miquel
  • Nitella spanioclema J.Groves & Bullock-Webster (Nitella flexilis var. spanioclema (J.Groves & Bullock-Webster)
  • Nitella tenuissima (Desv.) Kütz.
  • Nitellopsis obtusa (Desv.) J.Groves
  • Tolypella[verification needed] intricata (Trent. ex Roth) Leonh.
  • Tolypella nidifica (O.F.Müll.) Leonh. (= Tolypella nidifica var. nidifica)
  • Tolypella prolifera (Ziz. ex A.Braun) Leonh.

Other regions

  • Family Chaetosphaeridiaceae[7]
    • Chaetosphaeridium globosum (Nordst.) Klebahn, 1893
    • Chaetosphaeridium ovalis G. M. Smith, 1916
    • Chaetosphaeridium pringsheimii Klebahn, 1892
    • Conochaete comosa Klebahn, 1893[8]
    • Diplochaete solitaria Collins, 1901

Distribution

Ireland

  • Co. Antrim[9]
    • C.aspera Deth. ex Willd. var. aspera
    • C. globularis Thuill. var. globularis
    • C. vulgaris var. papillata Wallr. ex A. Braun
    • C. globularis var. virgata (Kützing) R.D.Wood
    • C. vulgaris L. var. vulgaris
    • C. vulgaris L. var. contraria (A.Braun ex Kützing) J.A. Moore
    • C. vulgaris var. longibracteata (Kützing) J. Groves & Bullock-Webster
    • C. vulgaris var. papillata Wallr. ex A. Braun
    • Nitella flexilis (L.) var. flexilis
    • Nitella translucens (Pers.) C.A. Ag.
    • Tolypella nidifica (O. Mill.) Leonh. var. glomerata (Desv.) R.D.Wood
  • Co. Down[9]
    • C. aspera Deth. ex Willd. var. aspera
    • C. aspera var. curta (Nolte ex Kützing) Braun ex Leonh.
    • C. globularis Thuill. var. globularis
    • C. vulgaris var. papillata Wallr. ex A. Braun
    • C. globularis var. virgata (Kützing) R.D.Wood
    • C. globularis var. annulata (Lilleblad) J.A.Moore
    • C. hispida L.
    • C. hispida var. hispida
    • C. hispida var. major (Hartm.) R.D. Wood
    • C. hispida var. rudis A. Braun
    • C. pedunculata Kützing
    • C. vulgaris L. var. vulgaris
    • C. vulgaris L. var. contraria (A.Braun ex Kützing) J.A. Moore
    • C. vulgaris var. longibracteata (Kützing) J. Groves & Bullock-Webster
    • C. vulgaris var. papillata Wallr. ex A. Braun
    • Nitella flexilis (L.) var. flexilis
    • Nitella translucens (Pers) C.A. Ag.
    • Tolypella nidifica (O. Mill.) Leonh. var. glomerata (Desv.) R.D.Wood
  • Co. Londonderry[9]
    • C.aspera Deth. ex Willd. var. aspera
    • C. vulgaris var. papillata Wallr. ex A. Braun
    • C. globularis Thuill. var. globularis
    • C. globularis var. virgata (Kützing) R.D.Wood
    • C. hispida L.
    • C. hispida var. hispida
    • C. vulgaris L. var. vulgaris
    • C. vulgaris L. var. contraria (A.Braun ex Kützing) J.A. Moore
    • C. vulgaris var. papillata Wallr. ex A. Braun
    • Nitella flexilis (L.) var. flexilis
    • Nitella translucens (Pers) C.A. Ag.
    • Tolypella nidifica (O. Mill.) Leonh. var. glomerata (Desv.) R.D.Wood
  • Co. Mayo.Recent records have been published from Clare Island.[10]
    • C. virgata Kützing
    • N. flexilis (Linnaeus) C.Agardh
    • N. translucens (Persoon) C.Agardh

Ecology

The Characeae are aquatic though some can survive in brackish or maritime habitats. They are to be found usually in still, clear, non-flowing, water attached by rhizoids. They can be pioneer colonizers or ephemerals.[11] They are usually found in low to medium nutrient-rich water and tend to disappear due to eutrophication.

Life history

The antheridia and oogonia are protected by a layer of sterile cells when mature; the oogonium is oblong in shape and consists of a single egg, while the spherical antheridium is packed with threadlike cells that produce spermatia. As a result, the Charales have the most complex structure of all green algae, if indeed they should be so labelled.

The possible ancestors of the land plants are also known as brittleworts or skunkweed. These curious labels arise from the fragility of their lime-encrusted stems, and from the foul odor these produce when stepped on.

Many botanists propose that the stoneworts and their relatives be placed in a phylum, division, sub-kingdom, or even kingdom by themselves, often named Charophyta. Their classification by taxonomists is currently undergoing much cladistic scrutiny. Further DNA and RNA analysis may prove the charophytes to be a crucial evolutionary link in the phylogenetic tree of life, the critical developmental step from the algae toward the non-vascular and then vascular land plants.

References

Further reading

  • Bryant, J. The stoneworts (Chlorophyta, Charales). In Guiry, M.D., John, D.M., Rindi, F. and McCarthy, T.K. 2007. New Survey of Clare Island. Royal Irish Academy. ISBN 978-1-904890-31-7.
  • Lloyd, James. 2007. "Cytoskeletal Structures Responsible for Cytoplasmic Streaming in Chara." St. Vincent-St. Mary High School in Accordance with Dr. Donald Ott of The University of Akron. (Science Inquiry)
  • Schaible, R. and Schubert, H. 2008. The ccurrence of sexual Chara canesces populations (Charophyceae) is not related to ecophysiological potentials with respect to salinity and irradiance. Eur. J. Phycol. 43: 309 - 316.
  • Desai, Udaysingh and Karande C.T. 2008. "Biodiversity of Charophytes from Kolhapur District, Maharashtra". Shivaji University, Kolhapur.

Further links

  • Images of Charales
  • Creating ponds and lakes for stoneworts in the UK
  • University California
  • in Ireland
ca:Caral

fr:Chara (algue)

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