Plant classification

 Plants are classified into the Kingdom Plantae, comprising eukaryotic, multicellular, and autotrophic organisms with cellulose cell walls. They are primarily divided into five major groups—Thallophyta (algae)

, 

Bryophyta (mosses)

, 

Pteridophyta (ferns)

, 

Gymnosperms (naked seeds)

, and 

Angiosperms (flowering plants)

—based on body structure, vascularity, and reproductive methods

.

Angiosperms

 

Angiosperm is defined as a group of flowering plants characterized by the presence of flowers and specialized reproductive structures such as carpels and stamens

Gymnosperms

 

The gymnosperms are commonly known as naked seed plants forming a distinct sub division of the seed plants. The term gymnosperm is derived from the two greek words, gymnos – means naked, sperma – means seed. In gymnosperm the seeds are freely exposed upon megasporophyll and not enclosed inside the ovary (unprotected).

Pteridophytes

 

A pteridophyte is a vascular plant with xylem and phloem that reproduces by means of spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden

Bryophytes

 

Bryophytes are a group of non-vascular, seedless land plants—comprising mosses, liverworts, and hornworts—that thrive in moist, shaded environments. As the most primitive land plants, they lack true roots, stems, or leaves, relying on rhizoids for anchorage and water absorption via osmosis

. They possess a dominant gametophyte generation, reproduce via spores, and are known as "amphibians of the plant kingdom" because they require water for fertilization

Alage

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Algae are a diverse group of photosynthetic, aquatic organisms ranging from microscopic phytoplankton to large seaweeds like kelp. They are eukaryotic (excluding cyanobacteria) and produce over 50% of Earth's atmospheric oxygen. Algae are crucial for aquatic ecosystems, serving as primary producers, but excessive growth causes harmful algal blooms.