Answer:
Gymnosperms are vascular plants with naked seeds. The important characters of gymnosperms are as follows:
(i) The plants are perennial forming a dominant flora in colder areas.
(ii) Leaves are generally dimorphic, foliage and scale leaves.
(iii) The foliage leaves do not have lateral veins, instead transfusion tissue occurs internally for lateral transport.
(iv) Sporophylls produce strobili or cones. Flowers are absent.
(v) Microsporophylls do not show distinction of filament and anther. Megasporophylls are also not rolled-like carpels.
(vi) Ovules are unitegmic (sometimes bitegmic in gnetales). Each ovule has a mass of tissue called nucleus. It is equivalent to megasporangium. A megaspore mother cell develops in it.
(vii) Female gametophyte develops archegonia.
(viii) Pollination brings pollen grains over the micropylar end of ovules (direct pollination), siphonogamy occurs.
(ix) Endosperm is gametophytic.
(x) Secondary growth is present in some gymnosperms. Vascular tissues are otherwise similar to those of pteridophytes with vessels present in gnetales.
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