Air fern
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Air fern | ||||||||||||||
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Sertularia argentea[1] (Linnaeus, 1758) |
Air fern or "Neptune plant" is a name given to a product that is in fact composed of a species of marine animal called Sertularia argentea, also known as the "sea fir".
These so-called "ferns" are dead and dried colonies of hydrozoans, colonies of marine hydroids, class Hydrozoa, phylum Cnidaria. Hydroids are related to corals and jellyfish.
These dried hydroid colonies are commonly sold as a curiosity, as a supposedly decorative "indoor plant", or as underwater decorations for aquaria in stores. They are sometimes labeled as "Neptune plants". Despite a superficial resemblance to plants, they are actually animal skeletons or shells. The dried colonies are often dyed green, but when soaked in water, the coloring will dissolve.
The fernlike branches of S. argenta are composed of many small, chitinous chambers where individual animals once lived. When the colony was alive, a polyp with numerous tentacles occupied each of the chambers, called hydrotheca.
Also note that sometimes dried bryozoa are sold as "air ferns."[2]
Most commercially sold air ferns are collected as a by-product by trawlers in the North Sea.
[edit] References
- ^ ITIS on Sertularia argentea. Retrieved on 2007-02-19.
- ^ Frank K. McKinney. The Bryozoa. International Bryozoology Association. Retrieved on 2007-02-17.