Mature poppy ovary. Light micrograph (LM) of a cross-section through a mature poppy ovary, which is incompletely divided by septa (membranes) that do not meet in the centre. The epidermis is blue/purple and the yellow/green spongy tissue (aerenchyma) contains a multitude of chlorophyll-containing cells (green). The cells' nuclei are shown in red and the air spaces within the spongy tissue in black. The septa become swollen where they bear ovules (female sex cells) and these swellings are called placentas. The vascular tissue is the red/purple patches. It supplies oxygen, carbon-dioxide, food and water for the nourishment of ovules, which develop into seeds if fertilised by the male sex cells in the pollen grains.