The term Silk Tree can refer to two different plants: the MIMOSA (6 letters) and the Siris (5 letters). The MIMOSA is a genus of flowering plants in the legume family Fabaceae, native to tropical and subtropical regions throughout the world. It is also known as the sensitive plant because its leaves fold inward when touched. The Siris is a species of flowering tree in the pea family Fabaceae, native to India and Sri Lanka. It is a deciduous tree with a spreading crown and fragrant yellow flowers.