Ancient Egyptian Plants
Ancient Egyptian plants included many which may not be familiar to you. The lotus and the papyrus plants, for instance, were (and are) very common in Egypt. Papyrus is a kind of reed which grows in marshy areas along the banks of the Nile River. Date palms grew all over Egypt, and other palms that people used to make palm oil.
There were not very many trees in ancient Egypt, because there isn't really enough water in that area to support big trees. When the Egyptians needed wood, they had to buy it from Lebanon, further north, and sail it south to Egypt on boats.
There were also plants which are more familiar in the United States like wheat, barley, lentils, chickpeas, figs, and various vegetables. Egypt was famous for producing huge amounts of wheat especially; under Roman rule a lot of the wheat was sent to Rome, and then later to Constantinople.
Farming & Food (The Ancient Egyptians), by Jane Shuter (1998). For kids.
Everyday Life in Ancient Egypt, by Lionel Casson (revised edition 2001). Not especially for kids, but pretty entertaining reading, and Casson knows what he's talking about.
More about the Egyptian environment
More about ancient Egypt
More about the African environment