Characteristics and classification of plants

Plant characteristics

The Kingdom of plants, vegetables or metaphytes includes eukaryotic living beings, without locomotive capacity, multicellular, with cells surrounded by a cell wall of cellulose, and with chloroplasts with which they carry out photosynthesis (autotrophic nutrition).

Plants arose about 500 million years ago from a group of aquatic protoctists resembling green algae. Although most plants live on land, the most primitive plants (mosses and ferns) still need water to reproduce. The rest of the plants, more evolved, have adapted to all environments because their cells form tissues and organs.

Botany is the science that deals with the study of plants.

Plants are autotrophs and, through photosynthesis, are capable of manufacturing organic matter from carbon dioxide, water and mineral salts.

Classification of plants

Plants are classified into three major divisions. Depending on whether or not they produce seeds, they are distinguished:

• Seedless plants. They are the cryptogams or plants with "hidden reproduction", they do not have flowers, or pollen, nor do they produce seeds. They include two divisions:
  • Bryophyte Division. They are the mosses.
  • Pteridophyta Division. They are the ferns.
• Plants with seeds: They are the spermatophytes or phanerogams or with "visible reproduction". They have flowers, produce pollen and seeds.
  • Spermatophyta Division. They are divided into two groups:
    • Gymnosperms. Plants that produce seeds but are not contained within a fruit, such as pine.
    • Angiosperms. They produce seeds that are contained within a fruit, such as the almond tree.

There are also other ways to classify plants:

• Bryophytes: Without corm.
• Cormophytes: they include the Pteridophytes and the Spermatophytes, plants that have a "corm" type structure, with root, stem and leaves, a structure that the Bryophytes do not have.

Or also, depending on whether or not they have specialized tissues forming conductive vessels through which the sap circulates:

• Non-vascular plants: they do not have conductive vessels through which the sap circulates. They are the Bryophytes.
• Vascular plants: Pteridophytes and Spermatophytes have vessels through which the sap circulates. Vascular plants have specialized organs to perform some functions.
  • Pteridophytes.
    • Rhizome, similar in function to roots.
    • Fronds, similar to leaves.
    • They don't have flowers.
  • Spermatophytes.
    • Vegetative organs.
      • Root. Stem.
      • Leaves.
      • Reproductive organ: the flower.