Spirodela
| Spirodela | |
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| Spirodela polyrrhiza | |
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| Genus: | Spirodela
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Spirodela is a genus of aquatic plant. It is one of several genera containing plants commonly called duckweed. Spirodela species are members of the Araceae under the APG II system. They were formerly members of the Lemnaceae.
Spirodela species are free-floating thalli, 2-5 plants may remain connected to each other. Plants are green, but may have a red or brown underside. Multiple roots (7 to 12) emerge from each thallus. Spirodela is larger (10 mm) than Lemna (2–5 mm, one root per thallus).
Certain species of Spirodela overwinter as turions, a dormant form that lacks air pockets and so sinks to the bottom of the pond. In spring turions rise to the surface and germinate to start a new population.
Spirodela often forms floating mats with related species, e.g. Lemna and Wolffia.
There are three species.[1] Spirodela punctata is sometimes treated as Landoltia punctata.[2]
Selected species
- Spirodela intermedia
- Spirodela oligorrhiza
- Spirodela polyrrhiza
- Spirodela punctata
- Spirodela sichuanensis
Notes
- ^ Flora of North America
- ^ Les, D. H. and D. J. Crawford. 1999. Landoltia (Lemnaceae), a new genus of duckweeds. Novon 9: 530-533.
References
- Landolt, E. (1986) Biosystematic investigations in the family of duckweeds (Lemnaceae). Vol. 2. The family of Lemnaceae - A monographic study. Part 1 of the monograph: Morphology; karyology; ecology; geographic distribution; systematic position; nomenclature; descriptions. Veröff. Geobot. Inst., Stiftung Rübel, ETH, Zurich.
External links
- Armstrong, W. (2005) Wayne Armstrong's treatment of the Lemnaceae.
- Cross, J.W. (2006). The Charms of Duckweed.
- The Duckweed Genome Project
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