There are so many plants and trees in our environment. They not only provide us with food, fuel, and many other important things, but also are a source of fresh air and joy that surrounds us everyday. There exist different types of plants, which have minute differences regarding color, structure, and numerous physiological differences.
Often, we miss these differences and similaritie, since many of these aspects are indiscernible to the human eye. The branch of science called Botany involves study of plants in detail, and also their classification. According to the principles of Botany, higher plants are divided into two main groups known as angiosperms and gymnosperms. The former are flowering plants, whereas the latter are non-flowering ones.
Besides the basic differences mentioned above, there exists a set of standard features that help to identify gymnosperms.
- They do not have an outer covering or shell around their seeds.
- A gymnosperm does not produce flowers barring a few exceptions.
- They are heterosporous, which means that they produce different male and female spores. The microspores develop into pollen grains, and the megaspores are present in an ovule.
- Gymnosperms produce cones.
- They do not bear fruits.
- They propagate via wind pollination
The word 'Gymnosperm' originates from the words gymnos meaning naked, and sperma meaning seed. The name is so because of the fact that seeds of gymnosperms are not surrounded by a protective wall, which exists in the angiosperms. They are further separated into four divisions, namely:
This is the largest division of gymnosperms, which includes Pines, Yews, Spruces, Junipers, Cedars, etc. These conifers are found in the high latitudes of the northern hemisphere. There also are several families belonging to this division. These are cone-bearing gymnosperms, which date back to the carboniferous period.
This division includes palm-like gymnosperms, not to mention the surviving order Cycadales, and other extinct orders. The cycads are slow-growing palm-like plants. These plants also have another characteristic feature - the leaves are borne together on the top of the trunk. The seeds are present on the surface of the scales of cones.
This group is relatively limited as it consists of only one member. The single living species of this division is the Ginkgo biloba from China.
These gymnosperms are truly unique due to the fact that they bear flowers - a property that is exclusively attributed to the angiosperms. In addition to this, the xylem of such plants contains pollen-producing structures, which resemble the stamens in angiosperms. Owing to this characteristic, these plants are considered as a link between gymnosperms and angiosperms. The plants included in this division are tropical lianas, joint-firs, and several other species.