|Researched by||Morvan Barnes||Refereed by||This information is not refereed.|
|Other common names||-||Synonyms||-|
Chara canescens can be distinguished from other stoneworts, including Chara pendunculata and Chara curta, by the gradual decrease in internode length throughout the stem and by all the bracts in each whorl being equal in length (Stewart & Church, 1992). Only female plants occur in northern Europe and the species reproduces asexually (Bryant & Stewart, 2002). When growing in shallow water Chara canescens behaves as an annual but in deeper water (up to 5m) it can be perennial. Only female plants of Chara canescens have been recorded in Northern Europe, the plant reproducing by parthenogenesis without fertilization (gametophyte cells, other than a fertilized egg, develop into the sporophyte).
Reproduction is entirely by spores (this species does not produce vegetative bulbils). Germination occurs in April May, and spores are produced in the summer ripening from mid-July onwards but may remain present throughout autumn and winter. Spores are likely to be spread by wildfowl after ingestion with other food (Casanova & Nicol, 2009). Historical evidence suggests that this species can spread to new sites where suitable conditions occur near to existing populations. Spore viability decreases markedly after a year. The exact growth rate is unknown, but the maximum size is likely to be reached within 3 months. Charophytes have a rapid colonization rate and are a pioneer species, which after disturbance can quickly recolonize from the spore bank of oocytes in the soil. As succession takes place, the stonewort species present change, and may be out-competed by other colonising species and vascular plants such as the common reed Phragmites australis. Chara canescens has a limited ability to compete with vascular plants and often grows in areas after recent disturbance. Stoneworts enhance water clarity by stabilising sediments and reducing water flow rates. They also provide an important habitat for a variety of fish, molluscs and invertebrates.
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Stewart, N.F., 2004. Important Stonewort Areas. An assessment of the best areas for stoneworts in the United Kingdom. Plantlife International, Salisbury, UK.
Botanical Society of Britain & Ireland, 2018. Other BSBI Scottish data up to 2012. Occurrence dataset: https://doi.org/10.15468/2dohar accessed via GBIF.org on 2018-09-25.
Cambridgeshire & Peterborough Environmental Records Centre, 2017. CPERC Combined Dataset. Occurrence dataset: https://doi.org/10.15468/npthhv accessed via GBIF.org on 2018-09-25.
NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.
Norfolk Biodiversity Information Service, 2017. NBIS Records to December 2016. Occurrence dataset: https://doi.org/10.15468/jca5lo accessed via GBIF.org on 2018-10-01.
OBIS (Ocean Biogeographic Information System), 2019. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2019-10-15
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Suffolk Biodiversity Information Service., 2017. Suffolk Biodiversity Information Service (SBIS) Dataset. Occurrence dataset: https://doi.org/10.15468/ab4vwo accessed via GBIF.org on 2018-10-02.
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Last Updated: 10/06/2009