What is the explanation of zygotic pistil?

A pistil formed by combining several carpels is called a compound stamen (pistil). Compound pistil, also known as syncarpous pistil, is formed by combining two or more carpels. The ovary is syncarpous and the style is separated from the stigma, such as castor, pear and Dianthus. Ovary combined with style and independent stigma, such as cotton and sunflower; There are ovaries, styles and stigmas, such as rape, citrus and tomato. The number of compound pistil carpels is usually related to the number of styles, stigmas and locules. And the shape or cracking of the fruit, so it can be used to judge the carpel number of a pistil, but it cannot be used as an absolute standard.