Name the 4 divisions of gymnosperms and two lines about it
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Answer:
Types of Gymnosperms
All gymnosperms are found in four major divisions of plants. The divisions are Ginkgophyta, Cycadophyta, Gnetophyta, and Coniferophyta. The division Ginkgophyta contains the Ginkgo Biloba or Maidenhair tree.
Answer:
Classification of Gymnosperms
The four divisions of Gymnosperms include
Pinophyta or coniferophyta
Cycadophyta
Ginkgophyta
Gnetophyta
Coniferophyta
The Coniferophyta division contains conifers, which have the greatest variety of species among gymnosperms. Most conifers are evergreen (retain their leaves throughout the year) and include some of the largest, tallest and oldest trees on the planet. Examples of conifers include pines, sequoias, firs, hemlock, and spruces. Conifers are an important economic source of lumber and products, such as paper, that are developed from wood. Gymnosperm wood is considered softwood, unlike the hardwood of some angiosperms.
The word conifer means "cone-bearer," a distinct characteristic common to conifers. Cones house the male and female reproductive structures of conifers. Most conifers are monoecious, meaning that both male and female cones can be found on the same tree.
Another readily identifiable trait of conifers is their needle-like leaves. Different conifer families, such as Pinaceae (pines) and Cupressaceae (cypresses), are distinguished by the type of leaves present. Pines have single needle-like leaves or needle-leaf clutters along the stem. Cypresses have flat, scale-like leaves along the stems. Other conifers of the genus Agathis have thick, elliptical leaves, and conifers of the genus Nageia have broad, flat leaves.
Cycadophyta
The Cycadophyta division of gymnosperms include cycads. Cycads are found in tropical forests and subtropical regions. These evergreen plants have a feather-like leaf structure and long stems that spread the large leaves out over the thick, woody trunk. At first glance, cycads may resemble palm trees, but they are not related. These plants can live for many years and have a slow growth process. The King Sago palm, for example, may take up to 50 years to reach 10 feet.
Unlike many conifers, cycad trees either produce only male cones (produce pollen) or female cones (produce ovules). Female cone-producing cycads will only produce seeds if a male is within the vicinity. Cycads rely mainly on insects for pollination, and animals aid in dispersal of their large, colorful seeds.
Ginkgophyta
Ginkgo biloba are the only surviving plants of the Ginkgophyta division of gymnosperms. Today, naturally-growing ginkgo plants are exclusive to China. Ginkgoes can live for thousands of years and are characterized by fan-shaped, deciduous leaves that turn yellow in autumn. Ginkgo biloba are quite large, with the tallest trees reaching 160 feet. Older trees have thick trunks and deep roots.
Ginkgoes thrive in well sunlit areas that receive lots of water and have plenty of soil drainage. Like cycads, ginkgo plants produce either male or female cones and have sperm cells that use flagella to swim toward the egg in the female ovule. These durable trees are fire-resistant, pest-resistant, and disease-resistant, and they produce chemicals thought to have medicinal value, including several flavinoids and terpenes with antioxidant, anti-inflammatory, and antimicrobial properties.
Gnetophyta
The gymnosperm division Gnetophyta has a small number of species (65) found within three genera: Ephedra, Gnetum, and Welwitschia. Many of the species from the genus Ephedra are shrubs that can be found in desert regions of the Americas or in the high, cool regions of the Himalayan mountains in India. Certain Ephedra species have medicinal properties and are the source of the decongestant drug ephedrine. Ephedra species have slender stems and scale-like leaves.
Gnetum species contain some shrubs and trees, but most are woody vines that climb around other plants. They inhabit tropical rain forests and have broad, flat leaves that resemble the leaves of flowering plants. The male and female reproductive cones are contained on separate trees and often resemble flowers, though they are not. The vascular tissue structure of these plants is also similar to that of flowering plants.