To start with, angiosperms “the flowering plants” (also well-known as Magnoliophyta or Angiospermae) is a diverse group of higher plants with a flower. This major group of land plants has more than 540 families, and around 250 000 species. They contain one of two groups of seed plants.
According to Olmstead (2007), “Angiosperms contain more than a quarter million recognized species…” (p. 538). Furthermore, Levin (2002) emphasized that “over 70 % of all angiosperm species have a ploidal level increase somewhere in their evolutionary histories” (as cited in Meyers & Levin, 2006, p. 1198).
A diverse group of the flowering plants are traditionally divided into two major classes: Magnoliopsida (dicotyledons), and Liliopsida (monocots).
The dicotyledons count six subclasses, 418 families, and around 190 000 species of plants (Magnoliidae, Dilleniidae, Hamamelididae, etc.).
In turn, the monocotyledons include five subclasses, 120 families, and more than 60 000 species (Alismatidae, Liliidae, Zingiberidae, etc.).
Talking about their structural modifications, it is possible to say that angiosperms have a huge number of distinctive features that differs them from other plants. The most distinguishing feature of the flowering plants is the pistil. After the process of fertilization, the ovary grows and gradually becomes a fetus, and the ovules develop into seeds. This is a widespread fact that some of the flowering plants bypass the process of forming a flower, pollination and seed dispersal. In this case, the plant forms a tuber, which replaces the seed and fruit (for example, the century plant (Agave Americana)).
Another method of reproduction is a form of asexual reproduction (vegetative). It is a process when the leaves, tubers or other organs give rise to new plants. Insects, birds and mammals are also involved in the plants’ pollination. In order to live and survive, the plants should adapt to the environment. That is why when the flowering plants have no chance to be pollinated by someone, they can develop seeds with the help of self-pollination. Thus, these specific structural modifications to leaves, stems, roots, or flowers help the plant to live and survive in its environment.
To sum up the above-stated information, it is possible to conclude that it is difficult to overestimate the importance of the flowering plants. Angiosperms are the most extensive group of the vegetable kingdom on our planet. Mostly, they predominate in the vegetation cover of the earth, such as forests, grasslands, wetlands, etc.
Meyers, L. A., & Levin, D. A. (2006). On the Abundance of Polyploids in Flowering Plants. Evolution, 60 (6), 1198-1206.
Olmstead, R. G. (2007). Phylogeny and Evolution of Angiosperms. BioScience, 57 (6), 537-538.