Seed (source code)
= Seed
A <seed> packages a <plant embryo>, a <seed food reserve> and a protective <seed coat>. It is a living starting point for a new <plant>, not merely stored food. In a mature <pea> <seed>, the large <cotyledons> hold reserves; other <seeds> retain substantial <endosperm>. These are alternative arrangements, not successive <germination> stages.<Biology 2e by Mary Ann Clark and others>[Biology 2e, §32.2 Development of the Seed, Figure 32.20 and the paragraph on pea cotyledons]{ref}
\Image[/seed-embryo-and-reserve-arrangements.png]
{title=Two arrangements of <plant embryo> and <seed food reserve>}
{description=Original schematic sections, not microscope images or scale drawings. <Cotyledons> belong to the <plant embryo>; <endosperm> is a distinct <plant tissue>.}
A useful reading exercise is to identify both the future <plant> and its initial food supply in each drawing. The large yellow area has the same role in both pictures, but it belongs to different <plant tissues>. Thus location and function alone do not establish tissue identity.
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