Immature Elm seeds.
Seeds are produced in several related 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, hence the name. (Some fruits have layers of both hard and fleshy material).
Seeds are produced in several related 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, hence the name. (Some fruits have layers of both hard and fleshy material).
In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones.
However, the seeds do become covered by the cone scales as they develop in some species of conifer.
Kinds of seeds
There are a number of modifications to seeds by different groups of plants. One example is that of the so-called stone fruits (such as the peach), where a hardened fruit layer ( the endocarp) surrounds the actual seed and is fused to it.
Many structures commonly referred to as "seeds" are actually dry fruits. Sunflower seeds are sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed.
Kinds of seeds
There are a number of modifications to seeds by different groups of plants. One example is that of the so-called stone fruits (such as the peach), where a hardened fruit layer ( the endocarp) surrounds the actual seed and is fused to it.
Many structures commonly referred to as "seeds" are actually dry fruits. Sunflower seeds are sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed.
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