Table of Contents
- 1 What morphological characteristic do gnetophytes share with flowering plants?
- 2 What are some examples of Gnetophyta?
- 3 What are the three genera of gnetophytes?
- 4 Are Cycadophyta gymnosperms?
- 5 What are Angiospermic characters of Gnetales?
- 6 How do you identify gnetophytes?
- 7 What are living gymnosperms?
- 8 Where can gymnosperms be found?
- 9 What do gnetophytes have in common with flowering plants?
- 10 Is the Gnetophyta a sister group to the conifers?
The gnetophytes share with the angiosperms a number of structural and developmental characteristics. One of these is the presence of water conducting tubes, called vessels, in the secondary xylem, orwood. Vessels, although present in angiosperms, do not occur in gymnosperms other than gnetophytes.
What are some examples of Gnetophyta?
Gnetophyta (/nɛˈtɒfɪtə, ˈnɛtoʊfaɪtə/) is a division of plants, grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: Gnetum (family Gnetaceae), Welwitschia (family Welwitschiaceae), and Ephedra (family Ephedraceae).
What are the three genera of gnetophytes?
gnetophyte, any member of the division Gnetophyta, a small group of gymnospermous vascular plants that are represented by three living genera: Ephedra, Gnetum, and Welwitschia.
Do gnetophytes need water to reproduce?
No liquid water is needed for the sperm to reach the egg and complete the life cycle. Summary of the two trends in gymnosperms: The gametophyte is much reduced. It exists as a haploid female gametophyte inside the female cones and the haploid pollen which delivers the sperm.
How do you identify Gnetophytes?
They bear evergreen broad-leaves with a net-like pattern of veins which gives an overall design that is very similar to angiosperm leaves. They also have a similar vascular tissue to angiosperms. Genetic analysis has however shown that they are gymnosperms and are more closely related to the pines.
Are Cycadophyta gymnosperms?
Cycads are gymnosperms (naked seeded), meaning their unfertilized seeds are open to the air to be directly fertilized by pollination, as contrasted with angiosperms, which have enclosed seeds with more complex fertilization arrangements.
What are Angiospermic characters of Gnetales?
Some of the characteristics common in both Gnetum and other gymnosperms are under mentioned:
- Wood having tracheids with bordered pits.
- No sieve tubes and companion cells are present.
- Presence of naked ovules.
- Absence of fruit formation because of the absence of ovary.
- Anemophilous type of pollination.
How do you identify gnetophytes?
Which plant needs water for fertilization?
Bryophytes though grow on soil but need water for sexual reproduction. The sperms of bryophytes are flagellated and eggs are non-motile. Each sperm has two flagella. So, in order to accomplish fertilization sperm must be provided with water.
What does Gnetophytes look like?
What are living gymnosperms?
- The gymnosperms (lit.
- The gymnosperms and angiosperms together compose the spermatophytes or seed plants.
- By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species).
Where can gymnosperms be found?
Gymnosperms are often found in temperate forest and boreal forest biomes. Common types of gymnosperms are conifers, cycads, ginkgoes, and gnetophytes.
What do gnetophytes have in common with flowering plants?
The gnetophytes have a number of features in common with the flowering plants (phylum Anthophyta, the angiosperms), which has sparked scientific interest in the evolutionary relationships between the two groups; they are the only gymnosperms, for example, in which vessels occur.
Is the possession of vessels a characteristic of a gnetophyte?
The possession of vessels is characteristic of the flowering plants ( angiosperms) as well, and has led to speculation that gnetophytes, especially Gnetum, may have been close to the ancestral stock of some angiosperms.
Are there any living members of the phylum Gnetophyta?
Gnetophytes The gnetophytes are a small group of vascular seed plants composing the phylum Gnetophyta, which is one of four phyla of gymnosperms that have living representatives. The Gnetophyta include only three genera Ephedra, Gnetum, and Welwitschia—each of which belongs to a separate family, in a single order, the Gnetales.
Is the Gnetophyta a sister group to the conifers?
A molecular biology study of Gnetum gnemon (Winter et al. 1999), however, found that conifers and gnetophytes are sister groups, and suggested that the evolution of flower-like reproductive structures may have occurred independently in gnetophytes and angiosperms.