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Curled up Selaginella tamariscinaSelaginella is a genus of plants in the family Selaginellaceae, which includes Spikemoss. Many workers still place the Selaginellales in the class Lycopodiopsida (often misconstructed as "Lycopsida"). This group of plants is included in what, for convenience, is called "fern allies Fern ally is a general term covering a somewhat diverse group of vascular plants that are not flowering plants and not true ferns. Like ferns, these plants disperse by shedding spores to initiate an alternation of generations". S. moellendorffii is an important model organism A model organism is a species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. In particular, model organisms are widely used to explore potential causes and treatments for human disease when human, and its genome was sequenced by the United States Department of Energy The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material. Its responsibilities include the nation's nuclear weapons program, nuclear reactor production for the United States Navy, energy conservation,'s Joint Genome Institute.[1]
Characteristics
Selaginellas are creeping or ascendant plants with simple, scale-like leaves on branching stems from which roots also arise. The plants are heterosporous In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoans. A chief difference between spores and seeds as dispersal units is that spores have very little stored (megaspores and microspores), and have structures called ligules, scale-like outgrowths near the base of the upper surface of each microphyll The terminology of fossil plants is in places a little confusing. In the discipline's 200+ year history, certain concepts have become entrenched, even though improved understanding has threatened the foundations upon which they are based. The traditional definition of microphylls and megaphylls will be employed in this article for simplicity; and sporophyll.
Unusually for the lycopods, each microphyll contains a branching vascular trace.
Species
There are about 700 species of Selaginella, showing a wide range of characters; the genus is overdue for a revision which might include subdivision into several genera. Better-known spikemosses include:
- Selaginella apoda - Meadow Spikemoss (eastern North America North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific Ocean; South America lies to the)
- Selaginella bifida (Rodrigues Island)
- Selaginella braunii - Arbor-vitae Fern (China China has one of the world's oldest civilizations and has the oldest continuous civilization. It has archaeological evidence dating back over 5,000 years. It also has one of the world's oldest written language systems, and is viewed as the source of many major inventions. Historically, China's cultural sphere has extended across East Asia as a)
- Selaginella bryopteris - Sanjeevani (India India, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal on the east, India has a coastline of 7,517)
- Selaginella canaliculata - Clubmoss (southeast Asia Southeast Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India and north of Australia. The region lies on the intersection of geological plates, with heavy seismic and volcanic activity, Maluku Islands The Maluku Islands are an archipelago in Indonesia, and part of the larger Maritime Southeast Asia region. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone. Geographically they are located east of Sulawesi (Celebes), west of New Guinea, and north of Timor. The islands were also historically known as the &)
- Selaginella densa - Lesser Spikemoss (western North America)
- Selaginella eclipes - Hidden Spikemoss (eastern North America)
- Selaginella kraussiana - Krauss's Spikemoss (Africa Africa is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people (as of 2009, see table) in 61 territories, it accounts for about 14.8% of the World's human population, Azores The Azores is a Portuguese archipelago in the Atlantic Ocean, about 1,500 km (930 mi) from Lisbon and about 3,900 km (2,400 mi) from the east coast of North America. The two westernmost Azorean islands (Flores and Corvo) actually lie on the North American plate. The Azores' most significant industries are tourism, cattle raising for milk and meat,)
- Selaginella lepidophylla Selaginella lepidophylla is a species of desert plant in the spikemoss family (Selaginellaceae). S. lepidophylla is noted for its ability to survive almost complete desiccation; during dry weather in its native habitat, its stems curl into a tight ball and uncurl when exposed to moisture. It is native to the Chihuahuan Desert - "Resurrection plant", "dinosaur plant" (Chihuahuan Desert The Chihuahuan Desert is a desert that straddles the U.S.-Mexico border. On the U.S. side it occupies the valleys and basins of central and southern New Mexico, Texas west of the Pecos River and southeastern Arizona; south of the border, it covers the northern half of the Mexican state of Chihuahua, most of Coahuila, north-east portion of Durango, of North America North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific Ocean; South America lies to the)
- Selaginella moellendorffii
- Selaginella rupestris - Rock Spikemoss or Festoon Pine (eastern North America)
- Selaginella selaginoides - Lesser Clubmoss (north temperate Europe Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, and by the Caucasus Mountains, the Kuma-Manych Depression, and the Black Sea to the southeast. Europe is washed, Asia Asia is the world's largest and most populous continent. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it provides 60% of the world's current human population. It is located in the eastern and northern hemispheres and North America North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific Ocean; South America lies to the)
- Selaginella uncinata - Peacock Fern
- Selaginella willdenovii - Electric Fern
Many species of Selaginella are desert A desert is a landscape or region that receives almost no precipitation. Deserts are defined as areas with an average annual precipitation of less than 250 millimetres per year, or as areas where more water is lost by evapotranspiration than falls as precipitation. In the Köppen climate classification system, deserts are classed as BWh (hot plants known as "resurrection plants", because they curl up in a tight, brown or reddish ball during dry times, and uncurl and turn green in the presence of moisture. Other species are tropical forest A forest is an area with a high density of trees. There are many definitions of a forest, based on the various criteria. These plant communities presently cover approximately 9.4% of the Earth's surface in many different regions and function as habitats for organisms, hydrologic flow modulators, and soil conservers, constituting one of the most plants that appear at first glance to be ferns A fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta. The group is also referred to as Polypodiophyta, or Polypodiopsida when treated as a subdivision of tracheophyta . The term "pteridophyte" has traditionally been used to describe all seedless.
Wallace's Selaginella (Selaginella wallacei)References
- ^ "Selaginella moellendorffii v1.0". Joint Genome Institute. United States Department of Energy The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material. Its responsibilities include the nation's nuclear weapons program, nuclear reactor production for the United States Navy, energy conservation,. 2007. http://genomeportal.jgi-psf.org/Selmo1/Selmo1.home.html. Retrieved 2009-04-08.
Categories: Lycopodiophyta | Selaginella
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