According to the theories of science & Botany, there was a time when there were no plants on earth. Then, hundreds of millions of years ago, tiny specks of protoplasm appeared on the earth. Protoplasm is the name for the living material that is found in both plants and animals. These original specks of protoplasm, according to this theory, were the beginnings of all our plants and animals.
The protoplasm specks that became plants developed thick walls and settled down to staying in one place. They also developed a kind of green colouring matter known’ as “chlorophyll”. This enabled them to make food from substances in the air, water and soil.
These early green plants had only one cell, but they later formed groups of cells. Since they had no protection against drying out, they had to stay in the water. Today, some descendants of these original plants still survive, though they have changed quite a bit. We call them “algae”.
One group of plants developed that obtained their food without the use of chlorophyll. These non-green plants are the “fungi”.
Most of the plants on earth today evolved the algae. Some of them came out of the sea and developed rootlets that could anchor them in the soil. They also developed little leaves with an outer skin covering, as protection against drying. These plants became mosses and ferns.
All the earliest plants reproduced either by simple cell division or by means of spores. Spores are little dustlike cells something like seeds, but containing no stored food in them as seeds do. As time went on, some of these plants developed flowers that produced true seeds.
Two different types of plants with seeds appeared; those with naked seeds and those with protected seeds. Each of these two types later developed along many different lines.
Types of Plants Available On This Planet Earth (Infographic)
According to ZMEScience; plants are grouped in 12 different phyla.