Spermatophytes (also known as phanerogam or phaenogam ) are any plant that produces seeds, hence the alternative name seed plant. They are descended from the Greek words spérmatos (seed) and phytón (plant), which means seed-bearing plants’. Spermatophytes are a subset of embryophytes, which are also known as land plants.
As opposed to cryptogamae (from the Ancient Greek (kruptós), which means “hidden,” phanerogams or phanerogamae are derived from the Greek (phanerós), which means “visible.” The term phanerogams or phanerogamae is derived from the Greek (phanerós), which means “visible.” These terms distinguished between plants that had hidden sexual organs (cryptogamae) and plants that had visible sexual organs (heterogamae) (phanerogamae).
Evolutionary history:
Three hundred and ninety-nine million years ago, a whole genome duplication event occurred in the ancestor of seed plants. In turn, this resulted in a series of evolutionary changes that eventually led to the evolution of seed plants.
Scientists have discovered a Middle Devonian (385 million year old) precursor to seeds in Belgium, which is approximately 20 million years older than the earliest seed plants on the planet. Runcaria is a small, radially symmetrical megasporangium surrounded by a cupule that is integumented on all sides. Unopened distal extension of the megasporangium protrudes above the multilobed integument of the megasporangium. Anemophilous (wind) pollination is suspected to have been accomplished through the use of the extension. The discovery of Runcaria sheds new light on the sequence of character acquisition that led to the discovery of the seed. In terms of characteristics, Runcaria is similar to seed plants, with the exception of having a solid seed coat and a system for guiding pollen to the seed.
Divisions of phanerogams:
The extant spermatophytes are divided into five divisions, the first four of which are traditionally classified as gymnosperms, plants with unenclosed, “naked seeds,” and the remaining two are classified as spermatophytes.
Cycadophyta, also known as the cycads, is a subtropical and tropical plant family that includes the genus Ginkgo, Pinophyta, also known as the conifers, which are cone-bearing trees and shrubs, and Gnetophyta, also known as the gnetophytes, which includes various woody plants from the extinct genera Ephedra, Gnetum, and Welwitschia.
Angiosperms, also known as magnoliophyta, are the fifth living division of spermatophytes, and they are the largest and most diversified group of all: blooming plants.
In contrast to gymnosperms, angiosperms, or flowering plants, have seeds that are enclosed within a fruit.
Furthermore, in addition to the five living species listed above, the fossil record contains evidence of numerous extinct species, among them the following:
“Seed ferns,” which are members of the Pteridospermae family, were among the first successful groups of land plants to emerge, and seed fern-dominated forests were widespread in the late Paleozoic epoch.
During the Permian period, Glossopteris was the most prominent tree genus on the ancient southern supercontinent of Gondwana, which was home to a large number of species.
By the Triassic period, seed ferns had lost their ecological significance, and representatives of modern gymnosperm groups had become abundant and dominant by the end of the Cretaceous period, when the angiosperms began to spread throughout the world.
Characteristics of phanerogams:
The following are some of the characteristics of Phanerogams:
- These plants are always multicellular and eukaryotic, which means they have more than one cell. The plant’s body is subdivided into distinct root systems, shoot systems, and leaf structures.
- Diploid and sporophytic organisms are representative of the major phase. Flowering plants are what they are commonly referred to as.
- They produce special reproductive structures as well as seeds as a result of their activity. Seeds are a container for the next generation. Spermatophyta are another name for this group of organisms.
- Sexual and vegetative reproduction are the modes of reproduction. They do not contain any asexual spores at all. Flowers (as well as cones and strobili) are reproductive structures in the plant kingdom.
- They demonstrate alternation in the generation process. There are two generations in which these plants complete their lifecycle: the sporophytic generation and the gametophytic generation.
- The gametophytic generation has been greatly reduced and is represented by cells in this system. They do not have a separate existence from the rest of us.
- With the exception of primitive Gymnosperms, flagellates male gametes are absent (Cycas has multiciliate male gametes). Siphonogamy is a technique that is used to bring gametes together to form a single reproductive unit.
- Oogamous sexual reproduction is the only type of sexual reproduction that exists.
Examples of phanerogams and cryptogams:
The following are some examples of Phenograms to consider:
Gymnosperms: Cycas, Pinus, Ginkgo, Gnetum, Ephedra.
Angiosperms: Sunflower, Rose, Mustards, Bamboo, Wheat.
The examples of cryptogams are, it includes non-photosynthetic organisms that are traditionally classified as plants, such as fungi, slime moulds, and bacteria, as well as the most well-known groups of cryptogams, which include algae, lichens, mosses, and ferns.
Conclusion:
Phanerogams are plants that bear seeds, as opposed to other plants. Spermatophytes are another term for these individuals.Spermatophytes (also known as phanerogam or phaenogam ) are any plant that produces seeds. Spermatophytes are a subset of embryophytes, which are also known as land plants.
The extant spermatophytes are divided into five divisions, the first four of which are traditionally classified as gymnosperms, plants with unenclosed, “naked seeds,” and the remaining two are classified as spermatophytes.
These plants are always multicellular and eukaryotic, which means they have more than one cell. The plant’s body is subdivided into distinct root systems, shoot systems, and leaf structures.Sexual and vegetative reproduction are the modes of reproduction. They do not contain any asexual spores at all. Flowers (as well as cones and strobili) are reproductive structures in the plant kingdom.