General Characteristics, Life Cycle, Evolution
The cycads are a relatively small phylum (Cycadophyta) in the plant kingdom Plantae. The cycads are considered to be gymnosperms, because they bear their seeds naked on modified leaves called sporophylls. In contrast, the evolutionarily more recent angiosperms (flowering plants) bear their seeds inside of ovaries. Cycads grow in tropical and subtropical regions of the world. Cycads are sometimes referred to as "living fossils" because they are very similar to extinct species that were much more abundant several hundreds of million years ago. The foliage of many species of cycads resembles that of palm trees, and plants in the genus Cycas are commonly called "Sago palms." However, cycads are only distantly related to the palms, and their similarity is superficial.
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