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Location of ovules inside a Helleborus foetidus flower. In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the integument, forming its outer layer, the nucellus (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its center.
An ovary with free central placentation, on the other hand, consists of a single compartment without septae and the ovules are attached to a central column that arises directly from the floral apex (axis). In some cases a single ovule is attached to the bottom or top of the locule (basal or apical placentation, respectively).
Diagram of an ovule in gymnosperms and angiosperms Photomicrograph of an ovule of a monocotyledon In angiosperms the gynoecium , also called pistil , consists of one or more carpels or carpel leaves that form a cavity, the ovary , inside which the ovules or seminal primordia are protected from both desiccation and attack by phytophagous insects.
The ovules are attached to parts of the interior ovary walls called the placentae. Placental areas occur in various positions, corresponding to various parts of the carpels that make up the ovary. See Ovule#Location within the plant. An obturator is present in the ovary of some plants, near the micropyle of each ovule.
Plant reproductive morphology is the study of the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers , which are the reproductive structures of angiosperms , are the most varied physically and show a correspondingly great diversity ...
Floral diagram of Anagallis arvensis. [1]: 307 The dot represents the main axis, green structure below is the subtending bract. Calyx (green arcs) consists of five free sepals; corolla (red arcs) consists of five fused petals. Antepetalous stamens are joined to petals by hairy filaments.
Diagram showing the stigma-style-ovary system of the female reproductive organ of a plant. The stigma is fixed to the apex of the style , a narrow upward extension of the ovary . The stigma ( pl. : stigmas or stigmata ) [ 1 ] is the receptive tip of a carpel , or of several fused carpels, in the gynoecium of a flower .
In seed plants, a structure called the ovule contains the female gametophyte. The gametophyte produces an egg cell. After fertilization, the ovule develops into a seed containing the embryo. [14] In flowering plants, the female gametophyte (sometimes referred to as the embryo sac) has been reduced to just eight cells inside the ovule.