Sinh học - Chapter 29: Plant diversity I: how plants colonized land

Ferns and other pteridiophytes are sometimes called seedless plants because there is no seed stage in their life cycles. The evolution of the seed in an ancestor common to gymnosperms and angiosperms facilitated reproduction on land. A seed consists of a plant embryo packaged along with a food supply within a protective coat. The first seed plants evolved about 360 million years ago, near the end of the Devonian. The early seed plants gave rise to the diversity of present-day gymnosperms, including conifers.