Seeds are produced in several interrelated groups of plants, and their manner of production distinguishes the angiosperms ("enclosed seeds") from the gymnosperms ("naked seeds"). Angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds. That is why some fruits have layers of both hard and fleshy material. In gymnosperms, there is not a special structure develops to enclose the seeds, which begin their development "naked" on the bracts of the cones. However, the seeds do become covered by the cone scales as they develop in some species of conifer.
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