Overview
The order Salviniales (formerly known as the Hydropteridales and including the former Marsileales) is an order of ferns in the Division Pteridophyta. They are all aquatic and differ from all other ferns in being heterosporous, meaning that they produce two different types of spores (megaspores and microspores) that develop into two different types of gametophytes (female and male gametophytes, respectively), and in that their gametophytes are endosporic, meaning that they never grow outside the spore wall and cannot become larger than the spores that produced them. In being heterosporus with endosporic gametophytes they are more similar to seed plants than to other ferns.
The ferns of this order vary radically in form from one another and do not look particularly fern-like. Species of the family Salviniaceae are natant (floating), while those of the family Marsileaceae are rooted. However, the natant species may temporarily grow on wet mud during times of low water, and the Marsileaceae may grow as emergent species, depending on species and location.
There is a well-known fossil member of the Marsileales, (incertae sedis).
- Smith, Alan R., Pryer, Kathleen M., Schuettpelz, E., Korall, P., Schneider, H., Wolf, Paul G. (2006). "A classification for extant ferns". Taxon 55(3): 705-731.
- C.Michael Hogan. 2010. Fern. Encyclopedia of Earth. National council for Science and the Environment. Washington, DC
Taxonomy
The Order Salviniales is further organized into finer groupings including:
- Family (3): Azollaceae · Marsileaceae · Salviniaceae
- Species: ZipcodeZoo has pages for 311 species, subspecies, varieties, forms, and cultivars in the Order Salviniales.
Families
Azollaceae
Azolla (mosquito fern, duckweed fern, fairy moss, water fern) is a genus of seven species of aquatic ferns in the family Salviniaceae. They are extremely reduced in form and specialized, looking nothing like conventional ferns but more resembling duckweed or some mosses. [more]
Marsileaceae
The Marsileaceae are a small family of heterosporous aquatic and semi-aquatic ferns, though at first sight they do not physically resemble other ferns. The group is commonly known as the "pepperwort family" or as the "water-clover family" because the leaves of the genus Marsilea superficially resemble the leaves of a four-leaf clover (a flowering plant). Leaves of this fern have sometimes been used to substitute for clover leaves on Saint Patrick's Day. In all, the family contains 3 genera and 50 to 80 species with most of those belonging to Marsilea. [more]
Salviniaceae
At least 96 species and subspecies belong to the Family Salviniaceae.
More info about the Family Salviniaceae may be found here.
References
- Smith, Alan R., Pryer, Kathleen M., Schuettpelz, E., Korall, P., Schneider, H., Wolf, Paul G. (2006). "A classification for extant ferns". Taxon 55(3): 705-731.
Sources
- The text on this page is licensed under the GNU Free Documentation License. It includes material from Wikipedia retrieved Wednesday, April 25, 2012.
- Photographs on this page are copyrighted by individual photographers, and individual copyrights apply.
- The technology underlying this page, including the controls behind Keep Exploring, is owned by the BayScience Foundation. All rights are reserved.