Peanut
Arachis hypogaea L. (1753)
The peanut is a member of the legume family. This family (Fabaceae) is the third largest family of flowering plants with more than 18,000 described species. It is surpassed in size only by the orchid family (Orchidaceae) with about 20,000 species and the sunflower family (Asteraceae) with about 24,000 species.
The peanut is a very particular plant. It has a complete do it yourself type of reproduction. It has no need for any intermediary whatsoever. In the first place it pollinates itself. After self-pollination and fertilization inside the flower, the peanut peduncle, or peg (the stalk that holds the flower) elongates and bends down into the ground. As it is growing, it forces the ovary into the ground. At the top of the ovary a cap of cells forms where the style was. This cap protects the ovary as it is pushed into the soil. [This is similar in function to the root cap at the tip of a root.] After the developing ovary has been pushed a few centimetres into the soil, downward elongation of the peg ceases. The ripening ovary becomes oriented parallel with the ground surface and completes its development. So it is a self-planting plant too.