👉 Hydnodontaceae is a subfamily of flowering plants within the family Apocynaceae, primarily found in tropical regions and subtropical forests worldwide. This group includes over 200 species that are commonly known as hydnodonts. These plants have distinctive leaves with an apical organ called the hydium, which provides protection against herbivory by small animals like ants and beetles. Their flowers often feature five petals or more, with a long, narrow stigma at