landplant

Land plants, or embryophytes, are a clade of photosynthetic eukaryotes that live primarily on terrestrial habitats. They range from small liverworts to massive trees and are characterized by adaptations that reduce water loss, protect embryos, and enable life-cycle transitions between generation stages. Land plants exhibit alternation of generations, with a haploid gametophyte producing gametes and a diploid sporophyte producing spores.

The major lineages are bryophytes (mosses, liverworts, hornworts), seedless vascular plants (ferns, lycophytes, horsetails), and seed plants (gymnosperms and angiosperms). Bryophytes lack true vascular tissue and have a gametophyte-dominated life cycle, relying on water for sperm transfer. Seedless vascular plants possess vascular tissue but reproduce with spores and have a sporophyte-dominant phase. Seed plants produce seeds and pollen, enabling spores to disperse through dry environments; in these lineages the sporophyte is the dominant phase and reproductive success is aided by protected embryos and reduced dependence on water for fertilization.

Key adaptations include a waxy cuticle, stomata, and multicellular embryos; true vascular tissue with lignified xylem and phloem in many lineages; and the evolution of seeds and, in angiosperms, flowers and fruits. These innovations facilitated colonization of diverse terrestrial environments and the diversification of forms.

Ecologically, land plants are primary producers and major drivers of biogeochemical cycles, soil formation, and habitat structure. They provide food, fibers, medicines, and materials, and they underpin most terrestrial ecosystems. Current diversity estimates place tens of thousands of plant species described, with flowering plants (angiosperms) representing the largest and most diverse group.