Spirodela

Taxobox
name = "Spirodela"

---

image_caption = "Spirodela polyrhiza"
regnum = Plantae
divisio = Magnoliophyta
classis = Liliopsida
ordo = Alismatales
familia = Araceae
subfamilia = Lemnaoideae
genus = "Spirodela"
subdivision_ranks = Species
subdivision = "Spirodela intermedia" "Spirodela polyrhiza" "Spirodela punctata"

"Spirodela" is a genus of aquatic plant, 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 thalii, 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 "Landoltia" (usually 3-6 mm with 2-3 roots per thallus) and "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 froms floating mats with related species, e.g. "Lemna" and Wolffia.

References and external links

*Armstrong, W. (2005) Wayne Armstrong's treatment of the Lemnaceae. [http://waynesword.palomar.edu/1wayindx.htm ] .
*Cross, J.W. (2006). The Charms of Duckweed. [http://www.mobot.org/jwcross/duckweed.htm]
*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.
* [http://lemna.rutgers.edu The Duckweed Genome Project]