Plant Kingdom Test - 9

The gymnosperms (gymnos : naked, sperma : seeds) are plants in which the ovules are not enclosed by any ovary wall and remain exposed, both before and after fertilisation. The seeds that develop post-fertilisation, are not covered, i.e., are naked. Since, Cycas has naked seeds, it belongs to gymnosperms.

Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores are known as heterosporous.

Selaginella belong to  class Lycopsida and other plants (Dryopteris, Pteris, Adiantum) belong to class Pteropsida of Pteridophytes.

One of the gymnosperms, Giant sequoias are the world's largest single tree with an average height of 50–85 m (164–279 ft) and 6–8 m (20–26 ft) in diamete

Equisetum of Pteridophyta belong to class Sphenopsida.

Unlike bryophytes and pteridophytes , in gymnosperms ( Cedrus )the male and the female gametophytes do not have an independent free-living existence.

Fern spores germinate to give rise to inconspicuous, small but multicellular, free-living, mostly photosynthetic thalloid gametophytes called prothallus.The gametophytes bear male and female sex organs called antheridia and archegonia.

The cones bearing megasporophylls with ovules or megasporangia are called macrosporangiate or female strobili.

In gymnosperms, male and female cones are formed that produce male and female gametes.The strobili bearing microsporophylls and microsporangia are called microsporangiate or male strobili. The cones bearing megasporophylls with ovules or megasporangia are called macrosporangiate or female strobili. So, cone of gymnosperms represents the reproductive organs.