Placenta is the tissue from which the ovum develops inside the uterus. The way in which the embryos are arranged inside the uterus is called placentation. Different types of placentation are-
1. Marginal: In a single-chambered uterus, if the amaranths are connected at one end, it is called Marginal amaranth. Eg- Beans, Beans, Aparajita etc.
2. Axile: In a multi-chambered uterus, if the amaras are attached to the axis, it is called axile amaravaryana. For example – millet, brinjal, dhutura, rajnigandha, rinds, banana etc.
3. Free central: If the amaras are connected to the central axis in a chambered uterus, it is called a free central amara arrangement. For example – Coriander, Mulberry, Nunia, Dianthus etc.
4. Paraietal: In a multi-chambered uterus, if the umbilical cords are connected at the ends, it is called Paraietal umbilical cord arrangement. For example – cucumber, gourd, mustard, pumpkin, papaya etc.
5. Basal: In a one-chambered uterus, if the embryos are attached to the base of the uterus, it is called Basal embryogenesis. For example – Paddy, Sunflower, Gada, Tridhara etc.
6. Apical: In a multi-chambered uterus, if the embryos are attached at the apex of the uterus, it is called Apical embryogenesis. For example – coriander, red leaf, croton etc.
7. Superficial: In a multi-chambered uterus, if the embryos are attached to the uterine cavity, it is called Superficial embryogenesis. Such as Shapla, Shaluk, Padma, Fox etc.