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Plant Kingdom
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Ectophloic siphonostele is found in -A siphonostele is a tubular stele in which the vascular tissue surrounds a central pith.
In an ectophloic siphonostele, the phloem is present only on the outer side of the xylem (external phloem), and the pith lies in the centre.
In an amphiphloic siphonostele (solenostele), phloem is present on both the outer and the inner sides of the xylem.
Ectophloic siphonosteles are found in Osmunda and Equisetum.
Amphiphloic siphonosteles are found in ferns such as Marsilea, Adiantum and Dicksonia.
So the ectophloic siphonostele is found in Osmunda and Equisetum. -
Top-shaped multiciliate male gametes, and the mature seed which bears only one embryo with two cotyledons, are characteristic features of -In most seed plants the male gametes are non-motile and are carried to the egg by the pollen tube.
Cycads (for example Cycas) are exceptional: their male gametes are very large, top-shaped and bear a spiral band of numerous cilia (multiciliate), so they are motile.
Although the ovule may contain more than one archegonium, the mature seed of Cycas usually bears only one embryo, with two cotyledons.
Conifers (such as Pinus) have non-motile male gametes and their embryos usually have several cotyledons.
Angiosperms have non-motile male gametes.
So these are the characteristic features of cycads.