Plants

Plants are multicellular eukaryotes that live primarily on land. They are autotrophic, obtaining energy through photosynthesis.

Plant cells are distinct because they have cell walls composed of cellulose. Chloroplasts inside the cells contain the pigment chlorophyll that is needed for photosynthesis.

Plants are classified according to whether they have vascular systems, produce seeds and develop flowers.

Nonvascular plants absorb water and nutrients directly from their surroundings. They are seedless and are considered to be the most ancient land plants. Examples include liverworts, mosses and hornworts.

Ferns, club mosses and horsetails are seedless vascular plants that reproduce using spores. The vascular tissues, xylem and phloem, carry water and nutrients throughout the plant.

Gymnosperms are vascular plants that produce seeds, but do not have flowers. The seeds of most gymnosperms develop in the scales of cones.

Angiosperms are flowering vascular plants that produce seeds inside a fruit.