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Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or on their own as in yew, Torreya, Ginkgo. [2] The life cycle of a gymnosperm involves alternation of generations , with a dominant diploid sporophyte phase, and a reduced haploid gametophyte phase, which is dependent on the sporophytic ...
Leaves are the fundamental structural units from which cones are constructed in gymnosperms (each cone scale is a modified megaphyll leaf known as a sporophyll) [6]: 408 and from which flowers are constructed in flowering plants. [6]: 445 Vein skeleton of a leaf. Veins contain lignin that make them harder to degrade for microorganisms.
Immature male or pollen cones of Rocky Mountain ponderosa pine. ( Pinus ponderosa var. scopulorum) A conifer cone or pinecone ( strobilus, pl.: strobili in formal botanical usage) is a seed-bearing organ on gymnosperm plants. It is usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in ...
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta ( / pɪˈnɒfɪtə, ˈpaɪnoʊfaɪtə / ), also known as Coniferophyta ( / ˌkɒnɪfəˈrɒfɪtə, - oʊfaɪtə /) or Coniferae. The division contains a single extant class, Pinopsida.
Gymnosperms are divided into 12 families of trees, shrubs and woody vines. Sequoiadendron giganteum, the giant redwood, is the largest tree in the world, and Sequoia sempervirens, the coastal redwood, is the tallest. Ginkgo trees tolerate urban pollutants well, and are often planted in and near cities.
Junipers vary in size and shape from tall trees, 20–40 metres (66–131 feet) tall, to columnar or low-spreading shrubs with long, trailing branches. They are evergreen with needle-like and/or scale-like leaves. They can be either monoecious or dioecious. The female seed cones are very distinctive, with fleshy, fruit -like coalescing scales ...
Cycas. Epicycas de Laub. Todda-pana Adans. Cycas is a genus of cycad, and the only genus in the family Cycadaceae with all other genera of cycad being divided between the Stangeriaceae and Zamiaceae families. Cycas circinalis, a species endemic to India, was the first cycad species to be described in western literature, and is the type species ...
The cotyledon of grasses and many other monocotyledons is a highly modified leaf composed of a scutellum and a coleoptile. The scutellum is a tissue within the seed that is specialized to absorb stored food from the adjacent endosperm. The coleoptile is a protective cap that covers the plumule (precursor to the stem and leaves of the plant).