part_of part of part of plant ovule nucellus nucelli (narrow, plural) A megasporangium (PO:0025201) in a seed plant, composed of fleshy subepidermal tissue that is part of a plant ovule (PO:0020003) and surrounds a megasporocyte (PO:0000431). nucelo (Spanish, exact) Poaceae nucellus (narrow) FNA:6ba590f7-80b0-4cf1-a378-a8e1286b7d18 PO:0020020 珠心 (Japanese, exact) PO_GIT:253 PO_GIT:49 PO_GIT:149 megasporangium (related) PO:0006492 Zea nucellus (narrow) PO:0006462 plant_anatomy In seed plants, the megaspores and megagametophyte are retained within the nucellus. If you are annotating to this structure for an angiosperm, please add an additional annotation to plant ovary ovule (PO:0025490). If you are annotating to this structure for an gymnosperm, please add an additional annotation to ovuliferous scale ovule (PO:0025491). If you are annotating to this structure for Zea mays or other grasses, please also add an annotation to the corresponding floret type. Choose the most specific term possible from: spikelet floret (PO:0009082), ear floret (PO:0006354), upper floret of pedicellate spikelet of ear (PO:0006350), upper floret of sessile spikelet of ear (PO:0006352). megasporangium