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Gnetum is a genus of about 30-35 species of gymnosperms Once an authoritative and major classification level in the plant kingdom, the gymnosperms form today a rather heterogeneous group of seed-bearing plants that includes conifers, cycads, Ginkgo and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of, the sole genus in the family Gnetaceae and order Gnetales. They are tropical The tropics is a region of the Earth by the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately 23° 26′ 16″ N and the Tropic of Capricorn in the southern hemisphere at 23° 26′ 16″ ( or 23.438° ) S. The tropics are also referred to as the tropical zone and the torrid zone (see evergreen In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during winter trees A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to 6 m; some authors set a minimum of 10 cm trunk diameter, shrubs A shrub or bush is distinguished from a tree by its multiple stems and lower height, usually less than 5–6 m tall. A large number of plants can be either shrubs or trees, depending on the growing conditions they experience. Small, low shrubs such as lavender, periwinkle and thyme are often termed subshrubs and lianas A liana is any of various long-stemmed, woody vines that are rooted in the soil at ground level and use trees, as well as other means of vertical support, to climb up to the canopy in order to get access to well-lit areas of the forest. Lianas are especially characteristic of tropical moist deciduous forests and rainforests. These climbers often. Unlike other gymnosperms they possess vessel elements A vessel element is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in the angiosperms but absent from most gymnosperms such as the conifers in the xylem In vascular plants, xylem is one of the two types of transport tissue, phloem being the other. The word "xylem" is derived from classical Greek ξυλον , "wood", and indeed the best-known xylem tissue is wood, though it is found throughout the plant. Its basic function is to transport water but it also transports some. Some species have been proposed to have been the first plants to be insect pollinated as they occur in association with the extinct pollinating scorpionflies.[1]
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Species
- Gnetum sect. Gnetum
- Gnetum subsect. Gnetum - 2 species of trees; southeast Asia Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.6% of the Earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population. During the 20th century Asia's population nearly quadrupled
- Gnetum subsect. Micrognemones - 2 species of lianas; tropical west 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 14.72% of the world's human population
- Gnetum africanum
- Gnetum buchholzianum
- Gnetum subsect. Araeognemones - 9 species of lianas; tropical South America South America is the southern continent of America, situated in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean; North America and the Caribbean Sea lie to the northwest and Central America Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. Central America is considered to be part of the Mesoamerican biodiversity hotspot, excluding the southern portions of Panama - Ituá
- Gnetum amazonicum
- Gnetum camporum
- Gnetum leyboldii
- Gnetum nodiflorum
- Gnetum paniculatum
- Gnetum schwackeanum
- Gnetum urens
- Gnetum venosum
- Gnetum sect. Scandentia - about 20 species of lianas; southern Asia
- Gnetum subsect. Stipitati
- Gnetum arboreum
- Gnetum contractum
- Gnetum gracilipes
- Gnetum latifolium
- Gnetum montanum
- Gnetum oblongum
- Gnetum pendulum
- Gnetum tenuifolium
- Gnetum ula
- Gnetum subsect. Sessiles
- Gnetum acutum
- Gnetum bosavicum
- Gnetum cleistostachyum
- Gnetum cuspidatum
- Gnetum diminutum
- Gnetum globosum
- Gnetum gnemonoides
- Gnetum hainanense
- Gnetum klossii
- Gnetum leptostachyum
- Gnetum loerzingii
- Gnetum luofuense
- Gnetum macrostachyum
- Gnetum microcarpum
- Gnetum neglectum
- Gnetum oxycarpum
- Gnetum parvifolium
- Gnetum raya
- Gnetum ridleyi
- Gnetum subsect. Stipitati
Uses
Many Gnetum species are edible, with the seeds A seed ( /ˈsiːd/ ) is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant. The formation of the seed completes the process of reproduction in seed being roasted, and the foliage used as a leaf vegetable Leaf vegetables, also called potherbs, green vegetables, greens, or leafy greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots. Although they come from a very wide variety of plants, most share a great deal with other leaf vegetables in nutrition and cooking methods. Some are also valued in herbal medicine Herbalism is a traditional medicinal or folk medicine practice based on the use of plants and plant extracts. Herbalism is also known as botanical medicine, medical herbalism, herbal medicine, herbology, and phytotherapy. The scope of herbal medicine is sometimes extended to include fungal and bee products, as well as minerals, shells and certain.
References
- ^ Ren D, Labandeira CC, Santiago-Blay JA, Rasnitsyn A, Shih CK, Bashkuev A, Logan MA, Hotton CL, Dilcher D. (2009). Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies. Science, 326 (5954), 840-847. doi A digital object identifier is a character string used to uniquely identify an electronic document or other object. Metadata about the object is stored in association with the DOI name and this metadata may include a location, such as a URL, where the object can be found. The DOI for a document is permanent, whereas its location and other metadata:10.1126/science.1178338
External links
- Gymnosperm Database - Gnetum
- Sorting Gnetum names
- Uses of Gnetum in Africa (FAO)
- in West African plants - A Photo Guide.
Categories: Gnetophyta | Medicinal plants Medicinal plants are plants which may have medicinal properties. Almost all our present medicines come from medicinal plants and are derived from research on medicinal plants.[citation needed]
