Very early plants do not have cell walls. As cell walls developed, plants were able to colonize land. Many of these early plants reproduced using spores. A great example of this is the fern. If you find a fern that has many small orange or brown dots under the leaf, you should put a leaf in a white paper bag and in a few days you will see little brown dust at the bottom of the bag. This dust is the spores. Later plants, would develop lignin which allowed them to grow into trees. However, these conifers still reproduced by, “gymnosperms” or “naked seeds”. The angiosperms are the most, “recent”evolutionary development. Angiosperms are flowering plants that have a seed that is encased with it’s own food supply.
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