Knowledge Tree
seed plants
Also known as: seed plant
Facts (12)
Sources
5.9.1: Kingdom Plantae - Evolution and Phylogeny bio.libretexts.org Nov 24, 2025 12 facts
claimSeed plants (spermatophytes) constitute the largest group of all existing plants.
measurementThere are more than 300,000 cataloged species of plants, with more than 260,000 of those being seed plants.
claimThe Permian period was dry, which provided a reproductive advantage to seed plants over the giant fern trees that dominated the preceding wet Mississippian and Pennsylvanian periods.
measurementThe earliest distinct seed plants appeared approximately 350 million years ago (Ma) according to the fossil record.
claimSeed plants include gymnosperms (such as conifers) which produce "naked seeds," and angiosperms which produce flowers.
claimGymnosperms are a diverse group of seed plants that are paraphyletic and characterized by naked seeds, separate female and male gametes, wind pollination, and the presence of tracheids for water and solute transport.
claimWhile seed plants developed adaptations to populate arid habitats, most seedless plants still require a moist environment.
claimThe fossil plant Elkinsia polymorpha, a "seed fern" from the Devonian period approximately 400 million years ago, is considered the earliest known seed plant.
claimSeeds and pollen are the two critical adaptations that distinguish seed plants from seedless vascular plants.
claimSeed plants include angiosperms and gymnosperms.
claimSeed plants, such as conifers and flowering plants, do not rely on water for reproduction, unlike seedless plants.
claimSeed ferns are considered the first true seed plants because they possessed cupules that enclosed and protected the ovule, the female gametophyte, and associated tissues, which developed into a seed upon fertilization.