Gymnosperm | Definition, Description, Plants, Examples, …
网页2024年8月31日 · At maturity, a gymnosperm embryo has two or more seed leaves, known as cotyledons. Cycads, Ginkgo, and gnetophytes have two cotyledons in the embryo; pine and other conifers may have several (eight is common; some have as many as 18).
Gymnosperm - Wikipedia
网页The leaves of many conifers are long, thin and needle-like, while other species, including most Cupressaceae and some Podocarpaceae, have flat, triangular scale-like leaves. Agathis in Araucariaceae and Nageia in Podocarpaceae have broad, flat …
Plant - Conifers, Cycads, Ginkgoes | Britannica
网页2024年9月13日 · The leaves of many gymnosperms have a thick cuticle and stomata below the leaf surface. The tree or shrub is the sporophyte generation. In conifers, the male and female sporangia are produced on separate structures called cones or strobili. Individual trees are typically monoecious (male and female cones are borne on the same tree).
Gymnosperms: Definition, Examples, and Reproduction
网页2018年5月2日 · Gymnosperms are flowerless plants that produce cones and seeds. The term gymnosperm literally means "naked seed," as gymnosperm seeds are not encased within an ovary. Rather, they sit exposed on the surface of leaf-like structures called bracts.
5.6.3: Gymnosperms - Biology LibreTexts
网页Conifers are the dominant phylum of gymnosperms, with the greatest variety of species (Figure 26.9). Typical conifers are tall trees that bear scale-like or needle-like leaves. Water evaporation from leaves is reduced by their narrow shape and a thick cuticle.
Gymnosperm - Definition, Examples and Life Cycle - Biology …
网页2017年4月27日 · “Gymnosperm”, from the Greek, gymnos, “naked” and sperma, “seed”, develop their seeds on the surface of scales and leaves, which often grow to form cone or stalk shapes, contrasting in characteristics from the angiosperms, flowering plants which enclose their seeds within an ovary.
26.2: Gymnosperms - Biology LibreTexts
网页Gymnosperm seeds are not enclosed in an ovary; rather, they are exposed on cones or modified leaves. Sporophylls are specialized leaves that produce sporangia. The term strobilus (plural = strobili) describes a tight arrangement of sporophylls around a central stalk, as seen in cones.
网页There are four groups of plants that make up the gymnosperms: the well-known conifers, plus the lesser known cycads, ginkgo, and the order Gnetales. These groups. Pine cones are perhaps the most familiar gymnosperm cone type. A mature eastern white pine (Pinus strobus) cone is seen here.
26.2C: Diversity of Gymnosperms - Biology LibreTexts
网页2023年10月31日 · Gymnosperms consist of four main phyla: the Coniferophyta, Cycadophyta, Gingkophyta and Gnetophyta. Conifers are the dominant plant of the gymnosperms, having needle-like leaves and living in areas where the weather is …
Characteristics of Gymnosperms - Biology Dictionary
网页2018年4月2日 · Most gymnosperms are evergreens meaning they don’t lose their leaves seasonally but there are a few species like the larch and tamarack that are deciduous. Gymnosperms are also perennials, growing back every year with no need for replanting. The reproductive system of gymnosperm plants is located in the cones.
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