Black stone flower or Kalpasi is a species of lichen used as spice in India. It has a sweet and strong earthy aromatic flavor and a very dry, light fluffy texture. When used in small quantities, it imparts a strong woody aroma and flavor to the preparation. For better results it should be roasted in a little oil to release its full aroma. It is widely used in Chettinad cuisine and to some extent in Hyderabadi and Marathi cuisine. Even kalpasi taste is very good in both vegetarian and non-vegetarian dishes.
The species occurs throughout the temperate Northern and Southern Hemispheres.