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Virginia meadow-beauty seed capsule. Light micrograph of a section through a Mexican marigold (Tagetes erecta) flower bud. A ring of bracts encloses the flower head in bud. This slice of flowers (florets) is shown at many levels. Level one shows one petal (purple-red) wrapped around the pistil/stigmas, Level two is the corolla - a ring (blue) with eight veins wrapped around the style (purple) and five anthers (red-yellow), each with four pollen sacs. Level three is the corolla - a ring (blue) with eight veins wrapped around the style (purple). Four is the ovary wall - a ring (blue and purple) wrapped around the ovule (purple-red, (right). Magnification: x3, when printed 10 centimetres wide. (KEYSTONE/SCIENCE PHOTO LIBRARY/DR KEITH WHEELER/SCIENCE PHOTO LIBRARY)