The Explanation About Gymnosperms

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The Explanation About Gymnosperms

The Explanation About Gymnosperms- Gymnosperms are plants that have opened-seed. Gymnosperms derived from the Greek, that gymnos means naked and sperm means seed, so it can be interpreted as gymnosperms seed plants yielding opened-seed. Gymnosperm is a group of seed plants that the seeds are not protected in the ovary (ovarium). Gymnosperms literally means gym = naked and spermae = plants that produce seeds. In flowering plants (Angiospermae or Magnoliphyta), seed or ovule is always protected fully by the ovaries that are not visible from the outside. In gymnosperms, the seeds visible (exposed) or located directly in between the leaves making up Strobilus or conifers.

Gymnosperms lived on Earth since the Devonian period (410-360 million years ago), before the era of dinosaurs. At that time, many gymnosperms are represented by groups which are now extinct, and now the coal: Pteridospermophyta (seed spikes), Bennettophyta and Cordaitophyta. Other members can continue their offspring until now. Encountered today angiosperms considered as the successor of one of the ancient group of extinct gymnosperms (seed spikes).

The Explanation About Gymnosperms

Gymnosperms derived from Progymnospermae through an evolution seeds process. This can be seen from the evidence of existing morphology. Furthermore Progymnospermae regarded as the ancestor of seed plants. Progymnospermae have characteristics that form between Trimerophyta and seed plants. Although this group produce spores, but its also resulted in the growth of secondary xylem and phloem as in gymnosperms. Progymnospermae also already have a vascular cambium bifasial capable of producing secondary xylem and phloem. Vascular cambium is characteristic of seed plants. One example is the type Aneurophyton Progymnospermae who lived at the Devon age, already shows a three-dimensional branching system with the protostele type. Another example is the type Archaeopteris who also lived at the time Devon age. This group is considered more advanced because it showed a flattened lateral branching system in the field and already has a structure that is considered as a leaf. The trunk has a stele of type eustele indicating kinship with seed plants that now.

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