Editing Seed (section)

=== Nutrient storage ===
<!-- Deleted image removed: [[File:Seed layers.jpg|thumb|Layers within an endospermic maize seed]] -->
Within the seed, there usually is a store of [[nutrient]]s for the [[seedling]] that will grow from the embryo. The form of the stored nutrition varies depending on the kind of plant. In angiosperms, the stored food begins as a tissue called the [[endosperm]], which is derived from the mother plant and the pollen via [[double fertilization]]. It is usually [[triploid]], and is rich in [[Vegetable oil|oil]] or [[starch]], and [[protein]]. In gymnosperms, such as [[Pinophyta|conifers]], the food storage tissue (also called endosperm) is part of the female [[gametophyte]], a [[haploid]] tissue. The endosperm is surrounded by the [[aleurone]] layer (peripheral endosperm), filled with proteinaceous aleurone grains.

Originally, by analogy with the animal [[ovum]], the outer nucellus layer ([[perisperm]]) was referred to as [[albumen]], and the inner endosperm layer as vitellus. Although misleading, the term began to be applied to all the nutrient matter. This terminology persists in referring to endospermic seeds as "albuminous". The nature of this material is used in both describing and classifying seeds, in addition to the embryo to endosperm size ratio. The endosperm may be considered to be farinaceous (or mealy) in which the cells are filled with [[starch]], as for instance [[cereal grains]], or not (non-farinaceous). The endosperm may also be referred to as "fleshy" or "cartilaginous" with thicker soft cells such as [[coconut]], but may also be oily as in ''[[Ricinus]]'' (castor oil), ''[[Croton (plant)|Croton]]'' and [[Poppy]]. The endosperm is called "horny" when the cell walls are thicker such as [[Date palm|date]] and [[Coffee bean|coffee]], or "ruminated" if mottled, as in [[nutmeg]], [[Palm (plant)|palms]] and [[Annonaceae]].<ref>{{cite web|url=https://books.google.com/books?id=waAMAAAAYAAJ&pg=PA155|title=The Encyclopædia Britannica, 9th ed. (1888) vol. 4 |page=155|work=google.ca|year=1888 }}</ref>

In most monocotyledons (such as [[Poaceae|grasses]] and [[Arecaceae|palms]]) and some ('''endospermic''' or '''albuminous''') dicotyledons (such as [[castor bean]]s) the embryo is embedded in the endosperm (and nucellus), which the seedling will use upon [[germination]]. In the '''non-endospermic''' dicotyledons the endosperm is absorbed by the embryo as the latter grows within the developing seed, and the cotyledons of the embryo become filled with stored food. At maturity, seeds of these species have no endosperm and are also referred to as '''exalbuminous''' seeds. The exalbuminous seeds include the [[legumes]] (such as [[bean]]s and [[pea]]s), trees such as the [[oak]] and [[walnut]], vegetables such as [[Squash (vegetable)|squash]] and [[radish]], and [[sunflower]]s. According to Bewley and Black (1978), Brazil nut storage is in hypocotyl and this place of storage is uncommon among seeds.<ref>Bewley & Black (1978) Physiology and Biochemistry of Seeds in Relation to Germination, pag.11</ref> All gymnosperm seeds are albuminous.